Chinese Journal of Applied Ecology

A conjecture on the fertilizer recovery measurement by field experiment

SHEN Shanmin

2005, 16(05): 781-782 .

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The measurement of fertilizer recovery either by isotope tracer technique or by field experiment with plots fertilized and unfertilized, both were suspected unreliable and reasons were discussed. Based on some reasonable presumptions, an alternative way of estimating fertilizer recovery by field trials was proposed in this paper, but further examination on it’s reliability is needed.

A conjecture on the fertilizer recovery measurement by field experiment

2005, 16(5): 781-782.

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The measurement of fertilizer recovery either by isotope tracer technique or by field experiment with plots fertilized and unfertilized, both were suspected unreliable and reasons were discussed. Based on some reasonable presumptions, an alternative way of estimating fertilizer recovery by field trials was proposed in this paper, but further examination on it's reliability is needed.

Litterfall in main forest ecosystems of Northeast China

LI Xuefeng^1,2,HAN Shijie¹,LI Yuwen³

2005, 16(05): 783-788 .

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A threeyear investigation on the litterfall of 15 forests in 4 different regions of Northeast China showed that the annual litterfall had a significant difference among forest types in the same region,but no significant difference was found between years.In the litterfall,leaf occupied 70% and more,while branch,flower and fruit were less than 20%.The branch production correlated positively with leaf production,and the correlation coefficient was 0.82. According to the investigation of 5 forest types in Changbai Mountain,the litterfall was 2.62～9.14 times higher in autumn and winter than in spring and summer.The peak of leaf-fall appeared in autumn,while that of branch and others withered evenly during a year.The litterfall of same forest type decreased with increasing latitude,and the relationships of the total and birch litterfall with latitude were established.Both the total and the birch litterfall were positively related to annual mean temperature,with the correlation coefficient 0.95 and 0.91,respectively.

Litterfall in main forest ecosystems of Northeast China

2005, 16(5): 783-788.

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A three-year investigation on the litterfall of 15 forests in 4 different regions of Northeast China showed that the annual litterfall had a significant difference among forest types in the same region,but no significant difference was found between years.In the litterfall,leaf occupied 70% and more,while branch,flower and fruit were less than 20%.The branch production correlated positively with leaf production,and the correlation coefficient was 0.82.According to the investigation of 5 forest types in Changbai Mountain,the litterfall was 2.62～9.14 times higher in autumn and winter than in spring and summer.The peak of leaf-fall appeared in autumn,while that of branch and others withered evenly during a year.The litterfall of same forest type decreased with increasing latitude,and the relationships of the total and birch litterfall with latitude were established.Both the total and the birch litterfall were positively related to annual mean temperature,with the correlation coefficient 0.95 and 0.91,respectively.

Plantation stocks and their affecting factors in western Liaoning Province

WANG Jian,LIU Zuoxin,CAI Congguang

2005, 16(05): 789-794 .

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Employing real-site investigation and data analysis methods,this paper analyzed the distribution of plantation stocks and its affecting factors in western Liaoning Province.The results showed that the average plantation stock of western Liaoning was 49.08 m³·hm^-2,which has been improved obviously since 1949.At the time of the third forest resource investigation,the plantation stock increased 20.19 m³·hm^-2,5.16 times higher than that of the first forest resource investigation.But,the general plantation stock of western Liaoning was still at a rather lower level,with only a 63.5% increase of the whole province and 51.1% of the national average plantation stock at the same period.The difference of plantation stock among cities in western Liaoning was observable,that even reached 68.47 m³·hm^-2.In general,the proportion of young forest was too high,reached to 49% of the total plantation,while the stock of mature forest was much lower,only 38% of the national average level.The plantation stock of national property was only 55.1% and 32.3% of the personal and collective property,respectively. Moreover,the plantation stock of timber forest was 36.4% lower than that of windbreak.Besides climatic factors,simple plantation structure,few forest tree species,and poor plantation management were the main causes of the low plantation stock.

Plantation stocks and their affecting factors in western Liaoning Province

2005, 16(5): 789-794.

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Employing real-site investigation and data analysis methods,this paper analyzed the distribution of plantation stocks and its affecting factors in western Liaoning Province.The results showed that the average plantation stock of western Liaoning was 49.08 m 3穐m^-2,which has been improved obviously since 1949.At the time of the third forest resource investigation,the plantation stock increased 20.19 m 3穐m^-2,5.16 times higher than that of the first forest resource investigation.But,the general plantation stock of western Liaoning was still at a rather lower level,with only a 63.5% increase of the whole province and 51.1% of the national average plantation stock at the same period.The difference of plantation stock among cities in western Liaoning was observable,that even reached 68.47 m 3穐m^-2.In general,the proportion of young forest was too high,reached to 49% of the total plantation,while the stock of mature forest was much lower,only 38% of the national average level.The plantation stock of national property was only 55.1% and 32.3% of the personal and collective property,respectively.Moreover,the plantation stock of timber forest was 36.4% lower than that of windbreak.Besides climatic factors,simple plantation structure,few forest tree species,and poor plantation management were the main causes of the low plantation stock.

Genetic diversity ofHepatacodium miconioides natural populations in Zhejiang Province

LI Junmin,JIN Zexin

2005, 16(05): 795-800 .

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Hepatacodium miconioides is the Class II protected plant species in China.This paper studied the genetic diversity and differentiation of its nine natural populations in Zhejiang Province by using random amplified polymorphic DNA (RAPD) technique.Twelve random primers were selected in the amplification, and 164 repetitive loci were produced.The percentage of polymorphic loci in eachH.miconioides population ranged from 14.60% to 27.44%,with an average of 20.73%.Among the test populations,Kuochangshan population had the highest percentage of polymorphic loci,Simingshan population took the second place,and Guanyinping population had the lowest one.As estimated by Shannon index,the genetic diversity within H.miconioides populations accounted for 27.28% of the total genetic diversity,while that among H.miconioides populations accounted for 72.72%.The genetic differentiation among H.miconioides populations as estimated by Nei index was 0.7157.The genetic differentiation estimated by Nei index was generally consistent with that estimated by Shannon index,i.e.,the genetic differentiation among populations was relatively high,but that within populations was relatively low.The gene flow among H.miconioides populations was relatively low (0.1987),and the genetic similarity ranged from 0.6557 to 0.8119,with an average of 0.7306.The highest genetic distance among populations was 0.4229,while the lowest one was 0.2083.All the results showed that there was a distinct genetic differentiation among H.miconioides populations.The genetic distance matrix of nine test populations was calculated by using the method,and the clustering analysis was made by using the unweighted pair group method with arithmetic mean (UPGMA).The cluster analysis suggested that the nine populations of H.miconioides in Zhejiang Province could be divided into two groups,i.e.,eastern Zhejiang group and western Zhejiang group.

Genetic diversity of Hepatacodium miconioides natural populations in Zhejiang Province

2005, 16(5): 795-800.

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Hepatacodium miconioides is the Class II protected plant species in China.This paper studied the genetic diversity and differentiation of its nine natural populations in Zhejiang Province by using random amplified polymorphic DNA (RAPD) technique.Twelve random primers were selected in the amplification,and 164 repetitive loci were produced.The percentage of polymorphic loci in each H.miconioides population ranged from 14.60% to 27.44%,with an average of 20.73%.Among the test populations,Kuochangshan population had the highest percentage of polymorphic loci,Simingshan population took the second place,and Guanyinping population had the lowest one.As estimated by Shannon index,the genetic diversity within H.miconioides populations accounted for 27.28% of the total genetic diversity,while that among H.miconioides populations accounted for 72.72%.The genetic differentiation among H.miconioides populations as estimated by Nei index was 0.7157.The genetic differentiation estimated by Nei index was generally consistent with that estimated by Shannon index,i.e.,the genetic differentiation among populations was relatively high,but that within populations was relatively low.The gene flow among H.miconioides populations was relatively low (0.1987),and the genetic similarity ranged from 0.6557 to 0.8119,with an average of 0.7306.The highest genetic distance among populations was 0.4229,while the lowest one was 0.2083.All the results showed that there was a distinct genetic differentiation among H.miconioides populations.The genetic distance matrix of nine test populations was calculated by using the method,and the clustering analysis was made by using the unweighted pair group method with arithmetic mean (UPGMA).The cluster analysis suggested that the nine populations of H.miconioides in Zhejiang Province could be divided into two groups,i.e.,eastern Zhejiang group and western Zhejiang group.

Effects of polyethylene glycol (PEG)-simulated drought stress on Pinus sylvestris var.mongolica seed germination on sandy land

ZHU Jiaojun¹,LI Zhihui²,KANG Hongzhang^1,3,FAN Yezhan⁴

2005, 16(05): 801-804 .

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With introduced sandy land Mongolian pine (Pinus sylvestris var.mongolica) seeds as test material,this paper studied the effects of polyethylene glycol (PEG)-simulated drought stress on their germination.The results showed that PEG could retard the germination of stressed seeds,and the germination rate,germination index,and germination potential were all decreased with increasing PEG concentration.The seeds treated with 30% PEG (about -1.20 MPa water potential) could not germinate at all throughout the experiment period,suggesting that 30% PEG or -1.20 MPa water potential was the threshold for the germination of Mongolian pine seeds. under 10% PEG stress (about -0.20 MPa water potential),the lengths of radicle and hypocotyl were shorter,illustrating their growth be more sensitive to PEG-simulated drought stress,while the radicle / hypocotyl ratio was increased with increasing PEG concentration,indicating that Mongolian pine seeds had a stronger resistance to drought stress after germination.Drought stress might be a possible cause that inhibited the natural regeneration of Mongolian pine on sandy land.

Effects of polyethylene glycol (PEG)-simulated drought stress on Pinus sylvestris varmongolica seed germination on sandy land

2005, 16(5): 801-804.

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With introduced sandy land Mongolian pine (Pinus sylvestris var.mongolica) seeds as test material,this paper studied the effects of polyethylene glycol (PEG)-simulated drought stress on their germination.The results showed that PEG could retard the germination of stressed seeds,and the germination rate,germination index,and germination potential were all decreased with increasing PEG concentration.The seeds treated with 30% PEG (about -1.20 MPa water potential) could not germinate at all throughout the experiment period,suggesting that 30% PEG or -1.20 MPa water potential was the threshold for the germination of Mongolian pine seeds.Under 10% PEG stress (about -0.20 MPa water potential),the lengths of radicle and hypocotyl were shorter,illustrating their growth be more sensitive to PEG-simulated drought stress,while the radicle / hypocotyl ratio was increased with increasing PEG concentration,indicating that Mongolian pine seeds had a stronger resistance to drought stress after germination.Drought stress might be a possible cause that inhibited the natural regeneration of Mongolian pine on sandy land.

Effects of exogenous nitric oxide on drought-resistance of poplar

WANG Miao¹,LI Qiurong²,FU Shilei¹,XIAO Dongmei¹,DONG Baili¹

2005, 16(05): 805-810 .

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This paper studied the effects of NO donor sodium nitroprusside (SNP) on the photosynthesis and active oxygen-scavenging enzyme activities of poplar leaves under drought stress.The results showed that SNP had a remarkable positive effect on leaf water content.When the SNP level was >500 μmol·L^-1, no significant difference in leaf water content was found between SNP treatments.SNP could increase photosynthesis rate,photochemical efficiency of PSII (Fv/Fm),and ratios of Fm/Fo and Fv/Fo,but the effects decreased with the prolongation of drought stress.The SOD and POD activities of poplar leaves were higher in short time (1 h) drought stress than in longer time (3 h) one.The activity of POD was increased by SNP,while that of SOD was changed little.With increasing SNP level,the POD and SOD activities first increased and then decreased.The NO donor could retard the accumulation of active oxygen through inducing POD and SOD activities,alleviate the effects of drought stress on photosynthesis,and increase the drought-resistance of poplar.

Effects of exogenous nitric oxide on drought-resistance of poplar

2005, 16(5): 805-810.

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This paper studied the effects of NO donor sodium nitroprusside (SNP) on the photosynthesis and active oxygen-scavenging enzyme activities of poplar leaves under drought stress.The results showed that SNP had a remarkable positive effect on leaf water content.When the SNP level was >500 μmol·L^-1,no significant difference in leaf water content was found between SNP treatments.SNP could increase photosynthesis rate,photochemical efficiency of PSII (F_v/F_m),and ratios of F_m/F_o and F_v/F_o,but the effects decreased with the prolongation of drought stress.The SOD and POD activities of poplar leaves were higher in short time (1 h) drought stress than in longer time (3 h) one.The activity of POD was increased by SNP,while that of SOD was changed little.With increasing SNP level,the POD and SOD activities first increased and then decreased.The NO donor could retard the accumulation of active oxygen through inducing POD and SOD activities,alleviate the effects of drought stress on photosynthesis,and increase the drought-resistance of poplar.

Dynamics of litterfall and its decomposition and nutrient return of shootused Dendrocalamus latiflorus in Mountainous areas of Fujian Province

QIU Erfa¹,CHEN Zhuomei²,ZHENG Yushan³,HONG Wei³,HUANG Baolong^{4 }

2005, 16(05): 811-814 .

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This paper studied the dynamics of nutrients in the litters of shoot-used Dendrocalamus latiflorus planted in Nanjing State-owned Forest Farm of Fujian Province.The results showed that the litterfall as well as its nutrient concentration and return varied obviously with seasons,and had a doublepeak curve change.The weight loss during litter decomposition was very fast at first,and then slowed down.There was a negative exponent correlation between remained weight and decomposition time.During decomposition,the concentrations of N and P in litter showed a trend of increase-decreaseincrease,while the K loss was intensive at the early stage,gently at midstage,and slight at late stage.

Dynamics of litterfall and its decomposition and nutrient return of shoot-used Dendrocalamus latiflorus in Mountainous areas of Fujian Province

2005, 16(5): 811-814.

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This paper studied the dynamics of nutrients in the litters of shoot-used Dendrocalamus latiflorus planted in Nanjing State-owned Forest Farm of Fujian Province.The results showed that the litterfall as well as its nutrient concentration and return varied obviously with seasons,and had a double-peak curve change.The weight loss during litter decomposition was very fast at first,and then slowed down.There was a negative exponent correlation between remained weight and decomposition time.During decomposition,the concentrations of N and P in litter showed a trend of increase-decrease-increase,while the K loss was intensive at the early stage,gently at mid-stage,and slight at late stage.

Spatial and temporal pattern of Castanopsis fargesii seed rain in evergreen broad-leaved forest in Tiantong National Forest Park of Zhejiang,China

HU Xingming,CAI Yongli,LI Kai,ZHANG Tianshu

2005, 16(05): 815-819 .

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Five mature plants of Castanopsis fargesii population were randomly chosen to study the spatial and temporal pattern of its seed rain in Tiantong National Forest Park,Zhejiang Province in 2003.The duration of seed rain observed from the five samples was about 45 days,from November 3rd to December 16th,with a distinguishable dropping peak between November 18th and 27th. The average seed rain density estimated from the traps deployed under the crown was 112.8 seeds·m^-2,ranging from 70 to 239.5 seeds·m^-2.Of the total acorns collected by seed traps,the viable accounted for 27.3%,the immature 25.7%,the eaten by rodents 5.0%,and the infected by larvae 42.0%.The acorns on the ground mainly distributed under the parent tree crown within 8 m from the trunk,and the spatial pattern of seed density on the ground fitted the quadratic distribution.

Spatial and temporal pattern of Castanopsis fargesii seed rain in evergreen broad-leaved forest in Tiantong National Forest Park of Zhejiang,China

2005, 16(5): 815-819.

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Five mature plants of Castanopsis fargesii population were randomly chosen to study the spatial and temporal pattern of its seed rain in Tiantong National Forest Park,Zhejiang Province in 2003.The duration of seed rain observed from the five samples was about 45 days,from November 3^rd to December 16^th,with a distinguishable dropping peak between November 18^th and 27^th.The average seed rain density estimated from the traps deployed under the crown was 112.8 seeds穖^-2,ranging from 70 to 239.5 seeds穖^-2.Of the total acorns collected by seed traps,the viable accounted for 27.3%,the immature 25.7%,the eaten by rodents 5.0%,and the infected by larvae 42.0%.The acorns on the ground mainly distributed under the parent tree crown within 8 m from the trunk,and the spatial pattern of seed density on the ground fitted the quadratic distribution.

Dynamic characters of sulphur and heavy metals concentrations in Pinus taiwanensis growth rings

WU Zemin,GAO Jian,HUANG Chenglin,HONG Shuyuan

2005, 16(05): 820-824 .

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Based on the concentration analyses of S,Mn,Fe,Zn,Cu and Pb in the growth ring set of Pinus taiwanensis at the summit (1 400～1 600 m alt.) of Huangshan Mountains during past 80 years,this paper studied the dynamic characters of element concentrations in the ring set,and their relationships with atmospheric environment.The results showed that there were three levels of S concentration in the growth ring set,i.e.,low concentration (less than 2 mg·kg^-1),accounted for 58.5% of the ring set; medium (3.65～6.0 mg·kg^-1),accounted for 24.4%; and high (>11.0 mg·kg^-1),accounted for 17.1%.The dynamic change of S accumulation in the ring set displayed an obvious fluctuation,which could be divided into 3 major types,i.e.,fluctuation during 1917～1960,relatively stable during 1961～1980,and gradual increase after 1981.In the growth ring set of 1935～1938,1959～1960,and recent 10 years,the S accumulation concentrations were all higher than 11 mg·kg^-1, suggesting the relatively high atmospheric S concentration in those periods. There was a significant correlation between the increase of tourist amount in Huangshan scenic spot and the S concentration in growth ring set.The fuel fume centralized in some places might result in the atmospheric pollution at local scale,which in turn,might influence the S accumulation in growth ring set.The Pb accumulation concentration in the ring set was less than the background value in soil.The accumulation concentrations of Mn,Fe,Zn and Cu showed fluctuation characteristics,with independence of each other.The accumulation of Zn and Cu in growth rings had no correlation with tree age, while that of Mn and Fe was in adverse.The Mn concentration in the growth ring set decreased with tree age but increased in recent growth rings, while the Fe concentration was on the contrary,which needed further study.

Dynamic characters of sulphur and heavy metals concentrations in Pinus taiwanensis growth rings

2005, 16(5): 820-824.

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Based on the concentration analyses of S,Mn,Fe,Zn,Cu and Pb in the growth ring set of Pinus taiwanensis at the summit (1 400～1 600 m alt.) of Huangshan Mountains during past 80 years,this paper studied the dynamic characters of element concentrations in the ring set,and their relationships with atmospheric environment.The results showed that there were three levels of S concentration in the growth ring set,i.e.,low concentration (less than 2 mg·kg^-1),accounted for 58.5% of the ring set; medium (3.65～6.0 mg·kg^-1),accounted for 24.4%; and high (>11.0 mg·kg^-1),accounted for 17.1%.The dynamic change of S accumulation in the ring set displayed an obvious fluctuation,which could be divided into 3 major types,i.e.,fluctuation during 1917～1960,relatively stable during 1961～1980,and gradual increase after 1981.In the growth ring set of 1935～1938,1959～1960,and recent 10 years,the S accumulation concentrations were all higher than 11 mg·kg^-1,suggesting the relatively high atmospheric S concentration in those periods.There was a significant correlation between the increase of tourist amount in Huangshan scenic spot and the S concentration in growth ring set.The fuel fume centralized in some places might result in the atmospheric pollution at local scale,which in turn,might influence the S accumulation in growth ring set.The Pb accumulation concentration in the ring set was less than the background value in soil.The accumulation concentrations of Mn,Fe,Zn and Cu showed fluctuation characteristics,with independence of each other.The accumulation of Zn and Cu in growth rings had no correlation with tree age,while that of Mn and Fe was in adverse.The Mn concentration in the growth ring set decreased with tree age but increased in recent growth rings,while the Fe concentration was on the contrary,which needed further study.

Landscape ecological evaluation of Fenglin Nature Reverse: Quantification and interpretation

GUO Qingxi^1,2,WANG Tianming²

2005, 16(05): 825-832 .

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Fenglin National Class Nature Reserve is the largest wellsaved virginal Korean pine（Pinus koraiensis） forest area and a precious species gene bank in China.In this study,the indexes diversity,naturalness,representativity, rarity，area suitability，stability,and anthropogenic interference were selected to establish a ranking ecological evaluation system to estimate the ecological condition of the Reserve.The value of each index was determined by the evaluation system,and the weight percentage was decided by Analytical Hierarchy Process(AHP).In the Reserve,there were 568 higher plant species belonging to 113 families and 220 higher animal species,with score 3 of species diversity.The zonal “climax" vegetation type broad-leaved Korean pine forest and the intrazonal community type spruce-fir forest constituted the principal part of the Reserve forest,which was the epitome of the virgin broadleaved Korean pine forest in Lesser Xing'an Mountains,with representativity score 3.During the past 20～30 years,the natural habitat in the Reserve was quite good,and secondary succession was obtained effective control with few natural or anthropogenic disturbance,with score 4 of naturalness and anthropogenic interference.There were a lot of ancient species of the tertiary period,such as Pinus koraiensis,Fraxinus mandsurica, Juglans mandshurica,Pellodendron amurense,Tilia amurensis and Acer mono,and Pinus koraiensis was listed as one of severe danger species by the FAO of UN,with rarity score 4.The Reserve covered an area of 18165 hm²,with an enough size to maintain the structure and function of the ecosystem. Accordingly,its area suitability score was 4.Broad-leaved Korean pine forest was the most typical and stable vegetation type in the Reserve,and thus,its stability score was 4.Finally,the composite evaluation index (CEI) was figured out as 0.87,showing that the ecological quality of the Reserve was very good,and the protection value was quite high.In conclusion,the present area,structure,and management of the Reserve could satisfy the requirement of sustainable development.

Landscape ecological evaluation of Fenglin Nature Reverse:Quantification and interpretation

2005, 16(5): 825-832.

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Fenglin National Class Nature Reserve is the largest well-saved virginal Korean pine(Pinus koraiensis) forest area and a precious species gene bank in China.In this study,the indexes diversity,naturalness,representativity,rarity,area suitability,stability,and anthropogenic interference were selected to establish a ranking ecological evaluation system to estimate the ecological condition of the Reserve.The value of each index was determined by the evaluation system,and the weight percentage was decided by Analytical Hierarchy Process(AHP).In the Reserve,there were 568 higher plant species belonging to 113 families and 220 higher animal species,with score 3 of species diversity.The zonal "climax" vegetation type broad-leaved Korean pine forest and the intrazonal community type spruce-fir forest constituted the principal part of the Reserve forest,which was the epitome of the virgin broad-leaved Korean pine forest in Lesser Xing'an Mountains,with representativity score 3.During the past 20～30 years,the natural habitat in the Reserve was quite good,and secondary succession was obtained effective control with few natural or anthropogenic disturbance,with score 4 of naturalness and anthropogenic interference.There were a lot of ancient species of the tertiary period,such as Pinus koraiensis,Fraxinus mandsurica,Juglans mandshurica,Pellodendron amurense,Tilia amurensis and Acer mono,and Pinus koraiensis was listed as one of severe danger species by the FAO of UN,with rarity score 4.The Reserve covered an area of 18165 hm²,with an enough size to maintain the structure and function of the ecosystem.Accordingly,its area suitability score was 4.Broad-leaved Korean pine forest was the most typical and stable vegetation type in the Reserve,and thus,its stability score was 4.Finally,the composite evaluation index (CEI) was figured out as 0.87,showing that the ecological quality of the Reserve was very good,and the protection value was quite high.In conclusion,the present area,structure,and management of the Reserve could satisfy the requirement of sustainable development.

GISbased forest fire risk zone mapping in Daxing'an Mountains

YIN Haiwei¹,KONG Fanhua^2,3,LI Xiuzhen²

2005, 16(05): 833-837 .

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In this study,the Yuying and Fendou forest farms of Tuqiang Forest Bureau in Daxing'an Mountains were chosen as test areas,and their vegetation type,altitude,slop,aspect,and settlement buffer were selected as the main forest fire factors.The circumstances of forest fire risk were quantified by the factor-weights union method with the support of GIS.Four classes of forest fire risk ranging from low to extreme were generated.The none,low, moderate, high,and extremely high fire risk zones accounted for 0.37%, 0.63%, 38.67%,58.63% and 1.70%,respectively,which was in corresponding with normal distribution.About 60.33% of the test areas were predicted to be upper moderate risk zones,indicating that the forest fire management task in these areas is super onerous.There was an obvious regional difference in the distribution of forest fire risk zones,being higher in the center and lower around the center,and the difference in fire factors was also obvious.The GIS-based forest fire risk model of test areas strongly cohered with the actual fire-affected sites in 1987,which suggested that the forest fire risk zone mapping had a higher reliability,and could be used as the reference and guidance of forest fire management.

GIS-based forest fire risk zone mapping in Daxing'an Mountains

2005, 16(5): 833-837.

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In this study,the Yuying and Fendou forest farms of Tuqiang Forest Bureau in Daxing'an Mountains were chosen as test areas,and their vegetation type,altitude,slop,aspect,and settlement buffer were selected as the main forest fire factors.The circumstances of forest fire risk were quantified by the factor-weights union method with the support of GIS.Four classes of forest fire risk ranging from low to extreme were generated.The none-,low,moderate,high,and extremely high fire risk zones accounted for 0.37%,0.63%,38.67%,58.63% and 1.70%,respectively,which was in corresponding with normal distribution.About 60.33% of the test areas were predicted to be upper moderate risk zones,indicating that the forest fire management task in these areas is super onerous.There was an obvious regional difference in the distribution of forest fire risk zones,being higher in the center and lower around the center,and the difference in fire factors was also obvious.The GIS-based forest fire risk model of test areas strongly cohered with the actual fire-affected sites in 1987,which suggested that the forest fire risk zone mapping had a higher reliability,and could be used as the reference and guidance of forest fire management.

Forest fire spread modeling and 3D visualization in virtual forest landscape

LI Jianwei¹,CHEN Chongcheng¹,YU Qizhi²,PAN Zhigeng²

2005, 16(05): 838-842 .

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The traditional method for simulating the behaviors of forest fire is to use a single ellipse to represent all of the fire points in fire scene,which has many disadvantages,e.g.,the simulated result is quite different to the real situation,and it is mainly based on 2D.As a result,the represented information is limited.In this paper,the most widely used Rothermel fire spreading model and the principal of Huygen were adopted to simulate the behaviors of forest fire in different position and wind direction,and the results were shown by pseudo-particle system in 3D,which could not only get the area of fire suffering,the direction of fire spreading and the size of fire,but also provide realistic simulation to observers.The method has been successfully applied to Zhangpu forest in Fujian Province.

Forest fire spread modeling and 3D visualization in virtual forest landscape

2005, 16(5): 838-842.

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The traditional method for simulating the behaviors of forest fire is to use a single ellipse to represent all of the fire points in fire scene,which has many disadvantages,e.g.,the simulated result is quite different to the real situation,and it is mainly based on 2D.As a result,the represented information is limited.In this paper,the most widely used Rothermel fire spreading model and the principal of Huygen were adopted to simulate the behaviors of forest fire in different position and wind direction,and the results were shown by pseudo-particle system in 3D,which could not only get the area of fire suffering,the direction of fire spreading and the size of fire,but also provide realistic simulation to observers.The method has been successfully applied to Zhangpu forest in Fujian Province.

Application of inverse Lagrangian dispersion analysis in simulating forest evapotranspiration

WANG Anzhi¹,DIAO Yiwei^1,2,JIN Changjie¹,GUAN Dexin¹,PEI Tiefan¹

2005, 16(05): 843-848 .

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Based on the localized near field (LNF) theory and coupled with the distribution of vertical velocity standard deviation (σw(z)) and Lagrangian integral time scales (TL(z)) within the canopy proposed by Raupach,the relationship between water vapor source/sink distribution and its mean concentration profile was constructed.The estimation of forest evapotranspiration was also conducted by the inverse Lagrangian dispersion analysis,which can calculate the water vapor source/sink distribution from its mean concentration profile.The calculated forest evapotranspiration was compared with the measured values.It was concluded that the simulated precision of the daily daytime evapotranspiration could reach 87.3%,the calculated results was 15%～25% higher than the measured one,the nighttime evapotranspiration was about 70% of the daily value,and the total monthly evapotranspiration from June to August was higher than that in May and September.

Application of inverse Lagrangian dispersion analysis in simulating forest evapotranspiration

2005, 16(5): 843-848.

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Based on the localized near field (LNF) theory and coupled with the distribution of vertical velocity standard deviation (σ_{w_(z)}) and Lagrangian integral time scales T_L(z) within the canopy proposed by Raupach,the relationship between water vapor source/sink distribution and its mean concentration profile was constructed.The estimation of forest evapotranspiration was also conducted by the inverse Lagrangian dispersion analysis,which can calculate the water vapor source/sink distribution from its mean concentration profile.The calculated forest evapotranspiration was compared with the measured values.It was concluded that the simulated precision of the daily daytime evapotranspiration could reach 87.3%,the calculated results was 15%～25% higher than the measured one,the nighttime evapotranspiration was about 70% of the daily value,and the total monthly evapotranspiration from June to August was higher than that in May and September.

Dynamic distribution characters of herbaceous vegetation root systems in abandoned grasslands of Loess Plateau

LI Peng^1,2,LI Zhanbin^1,2,3,TANTAI Zhan²

2005, 16(05): 849-853 .

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The investigation on the vertical distribution characters of herbaceous vegetation root systems in abandoned and natural grasslands of Loess Plateau by the method of soil auger showed that there were no significant differences in root system distribution patterns between different sampling points,and the related root indexes could be used to indicate the vertical distribution characters of vegetation roots.The main root indexes including root biomass and root length were decreased with increasing soil depth,but increased with increasing abandoned years.After abandoned for more than 20 years,the root distribution characters of abandoned grassland were approached to that of natural grassland.The root extinction coefficient decreased with increasing abandoned years,indicating that more and more roots were concentrated in surface soil layer with the increase of abandoned time,which was helpful to the improvement of soil physical and chemical properties,and beneficial to the new species intrusion and vegetation succession.

Dynamic distribution characters of herbaceous vegetation root systems in abandoned grasslands of Loess Plateau

2005, 16(5): 849-853.

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The investigation on the vertical distribution characters of herbaceous vegetation root systems in abandoned and natural grasslands of Loess Plateau by the method of soil auger showed that there were no significant differences in root system distribution patterns between different sampling points,and the related root indexes could be used to indicate the vertical distribution characters of vegetation roots.The main root indexes including root biomass and root length were decreased with increasing soil depth,but increased with increasing abandoned years.After abandoned for more than 20 years,the root distribution characters of abandoned grassland were approached to that of natural grassland.The root extinction coefficient decreased with increasing abandoned years,indicating that more and more roots were concentrated in surface soil layer with the increase of abandoned time,which was helpful to the improvement of soil physical and chemical properties,and beneficial to the new species intrusion and vegetation succession.

Dynamics of bud flow and bud bank of Phragmites communis population in dry land habitat of alkalinized meadow in the Songnen Plains of China

YANG Yunfei,WEI Chunyan,ZHANG Baotian,LIU Bao

2005, 16(05): 854-858 .

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In the dry land habitat of alkalinized meadow in Songnen Plains,the rhizomes of Phragmites communis population are distributed in different depths of one meter soil layer,which usually live for 6 years and a few for 7～9 years or even longer.Based on the investigation of their buds,a “bud flow" model of the population was established,and the method for estimating the dynamics of its bud bank storage,i.e.,adding the input rate of 1st year age-class rhizome buds to the storage rate of other age-classes dormant buds in the bank,was put forward.The results showed that the input rate of the bud bank increased with plant growth seasons while the burgeoned output rate exhibited a decreasing trend,whereas the output rate of the dead remained at a low level on the whole.By the end of September in the early dormant period,the input rate of the bud bank was as 2.04 times as its output rate,and the dormant buds of each age-class manifested a steady burgeoned output.Quantitative analysis indicated that the burgeoned output rate of dormant buds increased by 11% each year.In another word,11% of different age-classes dormant buds would germinate and form one-year class new rhizomes.The top of one-year class new rhizomes would develop to ramets in the next year,which would transport nutrients to nearby old-age rhizomes, and thus,maintain the vitality of old-age class rhizomes.

Dynamics of bud flow and bud bank of Phragmites communis population in dry land habitat of alkalinized meadow in the Songnen Plains of China

2005, 16(5): 854-858.

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In the dry land habitat of alkalinized meadow in Songnen Plains,the rhizomes of Phragmites communis population are distributed in different depths of one meter soil layer,which usually live for 6 years and a few for 7～9 years or even longer.Based on the investigation of their buds,a "bud flow" model of the population was established,and the method for estimating the dynamics of its bud bank storage,i.e.,adding the input rate of 1 st year age-class rhizome buds to the storage rate of other age-classes dormant buds in the bank,was put forward.The results showed that the input rate of the bud bank increased with plant growth seasons while the burgeoned output rate exhibited a decreasing trend,whereas the output rate of the dead remained at a low level on the whole.By the end of September in the early dormant period,the input rate of the bud bank was as 2.04 times as its output rate,and the dormant buds of each age-class manifested a steady burgeoned output.Quantitative analysis indicated that the burgeoned output rate of dormant buds increased by 11% each year.In another word,11% of different age-classes dormant buds would germinate and form one-year class new rhizomes.The top of one-year class new rhizomes would develop to ramets in the next year,which would transport nutrients to nearby old-age rhizomes,and thus,maintain the vitality of old-age class rhizomes.

Effects of environmental factors on AM fungi around steppe plant roots in Tibet Plateau

CAI Xiaobu¹,QIAN Cheng¹,PENG Yuelin¹,FENG Gu²,GAI Jingping²

2005, 16(05): 859-864 .

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The study on the representative steppe plant species in Tibet Plateau showed that the density of AM fungi spores in host plant rhizosphere did not correlate with the infection rate of AM fungi.The big changes in air temperature and rainfall at different altitudes played an important role in determining the growth and infection of AM fungi specific to steppe plants, and steppe type and soil texture also had obvious effects on AM fungi's growth and infection.Within a certain range,the spore density increased significantly with increasing soil pH (r=0.5319*,n=20),but showed a declining trend with the improvement of soil organic matter (r=-0.1973,n=20).In contrast,the infection rates of AM fungi to host plants were to some extent negatively and positively correlated with soil pH and soil organic matter,respectively.Phosphorus (P) enrichment in soil environment led to the inhibition of the reproduction and infection of AM fungi.The suitable soil pH,OM and Olsen P contents for the growth and reproduction of AM fungi ranged from 8.0～8.7,3.8～4.8 g·kg^-1 and 7.8～10.1 mg·kg^-1,respectively.Moderate and serious degradation of steppe (especially the serious degradation) had negative or detrimental impacts on the reproduction and infection of AM fungi. Reasonable grazing was helpful to the conservation of critical species of AM fungi.AM fungi also showed a relatively high infection rate on the roots of sedge species such as Carex praecpara,Kobresia humilis and Cyperus compressus.

Effects of environmental factors on AM fungi around steppe plant roots in Tibet Plateau

2005, 16(5): 859-864.

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The study on the representative steppe plant species in Tibet Plateau showed that the density of AM fungi spores in host plant rhizosphere did not correlate with the infection rate of AM fungi.The big changes in air temperature and rainfall at different altitudes played an important role in determining the growth and infection of AM fungi specific to steppe plants,and steppe type and soil texture also had obvious effects on AM fungi's growth and infection.Within a certain range,the spore density increased significantly with increasing soil pH (r=0.5319 *,n=20),but showed a declining trend with the improvement of soil organic matter (r=-0.1973,n=20).In contrast,the infection rates of AM fungi to host plants were to some extent negatively and positively correlated with soil pH and soil organic matter,respectively.Phosphorus (P) enrichment in soil environment led to the inhibition of the reproduction and infection of AM fungi.The suitable soil pH,OM and Olsen P contents for the growth and reproduction of AM fungi ranged from 8.0～8.7,3.8～4.8 g·kg^-1 and 7.8～10.1 mg·kg^-1,respectively.Moderate and serious degradation of steppe (especially the serious degradation) had negative or detrimental impacts on the reproduction and infection of AM fungi.Reasonable grazing was helpful to the conservation of critical species of AM fungi.AM fungi also showed a relatively high infection rate on the roots of sedge species such as Carex praecpara,Kobresia humilis and Cyperus compressus.

Effects of AM fungi on drought tolerance of citrus grafting seedling trifoliate orange/cara cara

WU Qiangsheng,XIA Renxue

2005, 16(05): 865-869 .

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With pot experiment in a greenhouse,this paper studied the effects of arbuscular mycorrhizal (AM) fungi Glomus mosseae on the drought tolerance of citrus grafting seedling trifoliate orange/cara cara under natural water stress and rewatering.The results showed that inoculation with AM fungi significantly increased the plant height,stem diameter,leaf area,and shoot length of test seedling.At the 4th day of rewatering,mycorrhizal plant had significantly higher root soluble protein content and superoxide dismutase (SOD) and catalase (CAT) activities than non-mycorrhizal plant.An interaction between water and AM fungi could significantly promote leaf SOD activity. During natural water stress and rewatering,AM fungi inoculation could decrease the leaf content of malondialdehyde (MDA),increase those of soluble sugar and soluble protein,and enhance the activities of SOD, peroxidase (POD) and CAT.As a result,the capability of osmotic adjustment and protective recovery,and thus,the drought tolerance of mycorrhizal citrus grafting seedling were improved.The mechanism that AM fungi could enhance the drought tolerance of host plant might be related to the protective system of host plant.

Effects of AM fungi on drought tolerance of citrus grafting seedling trifoliate orange/cara cara

2005, 16(5): 865-869.

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With pot experiment in a greenhouse,this paper studied the effects of arbuscular mycorrhizal (AM) fungi Glomus mosseae on the drought tolerance of citrus grafting seedling trifoliate orange/cara cara under natural water stress and rewatering.The results showed that inoculation with AM fungi significantly increased the plant height,stem diameter,leaf area,and shoot length of test seedling.At the 4^th day of rewatering,mycorrhizal plant had significantly higher root soluble protein content and superoxide dismutase (SOD) and catalase (CAT) activities than non-mycorrhizal plant.An interaction between water and AM fungi could significantly promote leaf SOD activity.During natural water stress and rewatering,AM fungi inoculation could decrease the leaf content of malondialdehyde (MDA),increase those of soluble sugar and soluble protein,and enhance the activities of SOD,peroxidase (POD) and CAT.As a result,the capability of osmotic adjustment and protective recovery,and thus,the drought tolerance of mycorrhizal citrus grafting seedling were improved.The mechanism that AM fungi could enhance the drought tolerance of host plant might be related to the protective system of host plant.

Dendrolimus spp.damage monitoring by using NOAA/AVHRR data

ZHANG Yushu¹,BAN Xianxiu¹,CHEN Pengshi¹,FENG Rui¹,JI Ruipeng¹,XIAO Yan²

2005, 16(05): 870-874 .

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This paper approached the feasibility of quantitatively monitoring Dendrolimus spp.damage by using NOAA/AVHRR data.The damaged rate of needle leaf was used to representDendrolimus spp.harming degree,and <30%,30%～60% and >60% of damaged rate was defined as low,medium and severe harming degree,respectively.The correlation equation of damaged rate and normalized vegetation index (NDVI) was established,based on the ground spectrum observation.The NDVI was 0.8823 when no damage occurred.A relative NDVI value of damaged to undamaged area was used to express the remote sensing index of low,medium and severe harming degree.The index was 1 for undamaged forest,and 0.78～1,0.57～0.78 and <0.57 for low, medium and severe harming degrees,respectively.The mixed pixels were separated by linear addable vertical vegetation index in the monitoring,and the quantitative monitoring and analysis was accomplished for years when the three damage degrees happened.It was shown that AVHRR data could be more available in quantitatively monitoring and analyzing serious damage, while low degree damage was difficult to distinguish by AVHRR data,due to the differences of surface properties and atmospheric influences, as well as the lower space resolution of NOAA/AVHRR.The damaged area estimated by AVHRR was 12.1%～14.3% lower than that by TM.

Dendrolimus sppdamage monitoring by using NOAA/AVHRR data

2005, 16(5): 870-874.

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This paper approached the feasibility of quantitatively monitoring Dendrolimus spp.damage by using NOAA/AVHRR data.The damaged rate of needle leaf was used to represent Dendrolimus spp.harming degree,and <30%,30%～60% and >60% of damaged rate was defined as low,medium and severe harming degree,respectively.The correlation equation of damaged rate and normalized vegetation index (NDVI) was established,based on the ground spectrum observation.The NDVI was 0.8823 when no damage occurred.A relative NDVI value of damaged to undamaged area was used to express the remote sensing index of low,medium and severe harming degree.The index was 1 for undamaged forest,and 0.78～1,0.57～0.78 and <0.57 for low,medium and severe harming degrees,respectively.The mixed pixels were separated by linear addable vertical vegetation index in the monitoring,and the quantitative monitoring and analysis was accomplished for years when the three damage degrees happened.It was shown that AVHRR data could be more available in quantitatively monitoring and analyzing serious damage,while low degree damage was difficult to distinguish by AVHRR data,due to the differences of surface properties and atmospheric influences,as well as the lower space resolution of NOAA/AVHRR.The damaged area estimated by AVHRR was 12.1%～14.3% lower than that by TM.

Dynamics of fluvo-aquic soil organic matter fractions under long-term fertilization

YIN Yunfeng,CAI Zucong,QIN Shengwu

2005, 16(05): 875-878 .

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By the method of relative density fractionation,this paper studied the dynamics of organic matter and its light and heavy fractions in a fluvoaquic soil under long-term fertilization.The results indicated under current fertilization system,the contents of soil organic matter and its light and heavy fractions were basically unchanged within 13 successive years of no fertilization, but had an increasing trend with the duration of chemical fertilizer NPK and organic manure applications,with a larger fluctuation among years and a less increment in treatment NPK.Regression analysis showed that soil organic matter and its light and heavy fractions had a linear correlation with the duration of fertilization in treatment NPK,and had a logarithm correlation in treatment organic manure.

Dynamics of fluvo-aquic soil organic matter fractions under long-term fertilization

2005, 16(5): 875-878.

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By the method of relative density fractionation,this paper studied the dynamics of organic matter and its light and heavy fractions in a fluvo-aquic soil under long-term fertilization.The results indicated under current fertilization system,the contents of soil organic matter and its light and heavy fractions were basically unchanged within 13 successive years of no fertilization,but had an increasing trend with the duration of chemical fertilizer NPK and organic manure applications,with a larger fluctuation among years and a less increment in treatment NPK.Regression analysis showed that soil organic matter and its light and heavy fractions had a linear correlation with the duration of fertilization in treatment NPK,and had a logarithm correlation in treatment organic manure.

Individual grain yield potential and nitrogen utilization efficiency of Zea mays cultivars widely planted in North China

WANG Kongjun^1,2,ZHANG Jiwang²,GUO Yuqiu²,HU Changhao²,DONG Shuting²,JIANG Gaoming¹

2005, 16(05): 879-894 .

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With field experiment and under low-density condition,this paper studied the individual grain yield (GY) and nitrogen utilization efficiency (NUE) of fifty Zea mays cultivars widely planted in North China since 1990s.Exploring analyses and normality tests showed that the 1000kernal weight (KW),above-ground biomass per plant (AB),grain harvest index (HI_G), NUE,and nitrogen harvest index (HI_N) were all conformed to normal distribution,with N(265.1,44.50²),N(322.3,36.91²),N(515.8,64.73²),N(0.514,0.06²),N(43.0,5.37²),and N(0.643,0.06²),respectively.The GY ranged from 198.35 to 345.22 g·plant^-1,KW from 241.50 to 391.82 g·1000 kernal^-1,AB from 402.34 to 712.84 g·plant^-1,HI_G from 0.39 to 0.63,NUE from 31.18 to 57.35 g grain·g N^-1,and HI_N from 0.47 to 0.74.Correlation analyses indicated that GY positively and significantly correlated with NUE (partial correlation coefficient was 0.471**,P=0.001),while KW negatively and significantly correlated with NUE (Pearson correlation coefficient was -0.427**,P=0.002).Through hierarchical cluster analyses for GY and NUE,the test Zea maysvarieties could be sorted into 3 types,i.e.,high-GY with high-NEU,low-GY with low-NEU,and mediate type.Currently,only 24 percent of Zea mays cultivars in North China were of high-GY with high-NEU type,and thus,its breeding should be strengthened in the future.

Individual grain yield potential and nitrogen utilization efficiency of Zea mays cultivars widely planted in North China

2005, 16(5): 879-884.

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With field experiment and under low-density condition,this paper studied the individual grain yield (GY) and nitrogen utilization efficiency (NUE) of fifty Zea mays cultivars widely planted in North China since 1990s.Exploring analyses and normality tests showed that the 1000-kernal weight (KW),above-ground biomass per plant (AB),grain harvest index (HI_G),NUE,and nitrogen harvest index (HI_N) were all conformed to normal distribution,with N(265.1,44.50 2),N(322.3,36.91 2),N(515.8,64.73 2),N(0.514,0.06 2),N(43.0,5.37 2),and N(0.643,0.06 2),respectively.The GY ranged from 198.35 to 345.22 g穚lant^-1,KW from 241.50 to 391.82 g?1000 kernal^-1,AB from 402.34 to 712.84 g穚lant^-1,HI_G from 0.39 to 0.63,NUE from 31.18 to 57.35 g grain穏 N^-1,and HI_N from 0.47 to 0.74.Correlation analyses indicated that GY positively and significantly correlated with NUE (partial correlation coefficient was 0.471^**,P=0.001),while KW negatively and significantly correlated with NUE (Pearson correlation coefficient was -0.427^**,P=0.002).Through hierarchical cluster analyses for GY and NUE,the test Zea mays varieties could be sorted into 3 types,i.e.,high-GY with high-NEU,low-GY with low-NEU,and mediate type.Currently,only 24 percent of Zea mays cultivars in North China were of high-GY with high-NEU type,and thus,its breeding should be strengthened in the future.

Allelopathy and resources competition of rice under different nitrogen supplies

XIONG Jun，LIN Wenxiong,ZHOU Junjian,WU Minhong,CHEN Xiangxu,HE Huaqin,GU O Yuchun,LIANG Yiyuan

2005, 16(05): 885-889 .

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In order to explore the bio-interference of allelopathic rice with barnyardgrass under different nitrogen supplies,a new bioassay method, i.e.,allelopathy-competition separation based (ACS) approach was recommended in this study.The results indicated that ACS could be successfully used to distinguish the rice allelopathy from its resources competition in rice-weed co-culture system,and to evaluate its response characteristics under different N supplies.The test rice accession PI312777 had a higher ability in interfering target weed barnyardgrass (BYD), represented by its stable and higher ability in resources competition,as well as its increasing allelopathic potential in suppressing companion weed BYD when the N supply decreased in the co-cultured system.The reverse was true in the case of rice accession Lemont,which had a lower allelopathic potential under all N supply levels,and a lower ability in resources competition under normal or rich N supply.But,Lemont had an obviously increased ability in resources competition under lower N supply,which was considered as the result of econiche competition in rice-weed system.

Allelopathy and resources competition of rice under different nitrogen supplies

2005, 16(5): 885-889.

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In order to explore the bio-interference of allelopathic rice with barnyardgrass under different nitrogen supplies,a new bioassay method,i.e.,allelopathy-competition separation based (ACS) approach was recommended in this study.The results indicated that ACS could be successfully used to distinguish the rice allelopathy from its resources competition in rice-weed co-culture system,and to evaluate its response characteristics under different N supplies.The test rice accession PI312777 had a higher ability in interfering target weed barnyardgrass (BYD),represented by its stable and higher ability in resources competition,as well as its increasing allelopathic potential in suppressing companion weed BYD when the N supply decreased in the co-cultured system.The reverse was true in the case of rice accession Lemont,which had a lower allelopathic potential under all N supply levels,and a lower ability in resources competition under normal or rich N supply.But,Lemont had an obviously increased ability in resources competition under lower N supply,which was considered as the result of econiche competition in rice-weed system.

Interactive effects between allelochemical substitutes

HE Huaqin,SHEN Lihua,SONG Biqing,GUO Yuchun,LIANG Yiyuan,LIANG Kangjing, LIN Wenxiong

2005, 16(05): 890-894 .

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In order to understand the allelopathic mechanisms of rice on weed,the allelochemical substitutes salicylic acid,p-hydroxybenzonic acid,cinnamic acid,vanillic acid and ferulic acid were used in an orthogonally gyrating regression experiment to study their interactive effects on the growth of barnyardgrass.The results indicated that whether the interactive effects between two substitutes,e.g.,between salicylic and cinnamic acid or between salicylic and phydrobanzonic acid,were synergistic or antagonistic depended on the concentrations of each substitutes in the mixture.In the mixture of salicylic acid and p-hydrobanzonic acid,the effect of salicylic acid was synergistic at <0.14 mmol·L^-1 but antagonistic at >0.14 mmol·L^-1, while p-hydrobanzonic acid showed an antagonistic effect at >0.425 mmol·L^-1.Salicylic acid at all test concentrations exhibited antagonism to cinnamic acid,while cinnamic acid had a synergistic at <0.14 mmol·L^-1,but an antagonistic effect at >0.14 mmol·L^-1 on alicylic acid.The interactive effects between cinnamic and ferulic acid were all synergistic at test concentrations.

Interactive effects between allelochemical substitutes

2005, 16(5): 890-894.

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In order to understand the allelopathic mechanisms of rice on weed,the allelochemical substitutes salicylic acid,p-hydroxybenzonic acid,cinnamic acid,vanillic acid and ferulic acid were used in an orthogonally gyrating regression experiment to study their interactive effects on the growth of barnyardgrass.The results indicated that whether the interactive effects between two substitutes,e.g.,between salicylic and cinnamic acid or between salicylic and p-hydrobanzonic acid,were synergistic or antagonistic depended on the concentrations of each substitutes in the mixture.In the mixture of salicylic acid and p-hydrobanzonic acid,the effect of salicylic acid was synergistic at <0.14 mmol稬^-1 but antagonistic at >0.14 mmol稬^-1,while p-hydrobanzonic acid showed an antagonistic effect at >0.425 mmol稬^-1.Salicylic acid at all test concentrations exhibited antagonism to cinnamic acid,while cinnamic acid had a synergistic at <0.14 mmol稬^-1,but an antagonistic effect at >0.14 mmol稬^-1 on alicylic acid.The interactive effects between cinnamic and ferulic acid were all synergistic at test concentrations.

Effects of pesticides metolachlor and S-metolachlor on soil microorganisms in quisols of Southern China Ⅰ.Catalase activity

ZHOU Ying^1,2,LIU Weiping¹,WANG Tingting²

2005, 16(05): 895-898 .

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This paper studied the effects of different concentrations (0,5,20,and 100 mg·kg^-1) metolachlor and its enantiomer S-metolachlor (Dual Gold) on soil catalase activity.The results showed that 20 mg·kg^-1 metolachlor had the most successive stimulating effect,5 mg·kg^-1 metolachlor had an inhibitory effect in the early period,while 100 mg·kg^-1 metolachlor had a stimulating effect in the late period.Different concentrations Dual Gold displayed a tendency stimulation-inhibition-stimulation.5 and 100 mg·kg^-1 metolachlor might have more damage on soil ecosystem than different concentrations Dual Gold.

Effects of pesticides metolachlor and S-metolachlor on soil microorganisms in aquisols of Southern China Ⅰ Catalase activity

2005, 16(5): 895-898.

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This paper studied the effects of different concentrations (0,5,20,and 100 mg穔g^-1) metolachlor and its enantiomer S-metolachlor (Dual Gold) on soil catalase activity.The results showed that 20 mg穔g^-1 metolachlor had the most successive stimulating effect,5 mg穔g^-1 metolachlor had an inhibitory effect in the early period,while 100 mg穔g^-1 metolachlor had a stimulating effect in the late period.Different concentrations Dual Gold displayed a tendency stimulation-inhibition-stimulation.5 and 100 mg穔g^-1 metolachlor might have more damage on soil ecosystem than different concentrations Dual Gold.

Forms and bio-availabilities of exogenous arsenic in purple soils

MIAO Jinyan¹,HE Feng²,WEI Shiqiang³,LIU Gang³

2005, 16(05): 899-902 .

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This study showed that after As was added into purple soils for 10 days, 50.2%～61.1％ of it transformed into residual As,occupying 68%～86％ in original soils.For acid purple soil,the As forms were Al-As >Fe-As>Ca-As;for neutral purple soil,they were Ca-As>Al-As>Ca-As>Fe-As>A-As,and for calcic purple soil,they were Ca-As>Al-As>Fe-As>A-As.It is suggested that NH₄Cl could be used as common extractant for different soils,because it slightly affected original As forms in soils,and showed a highly significant correlation (P=0.01) to plant absorption.From pluralistic regressive analysis of plant As content and each As form,Al-As and Fe-As were the main available forms in acid purple soil,but A-As and Ca-As were the most important fractions in neutral and calcic purple soils.The study also showed that H₃BO₃ could restrain the F interference in the operation of As speciation separations.

Forms and bio-availabilities of exogenous arsenic in purple soils

2005, 16(5): 899-902.

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This study showed that after As was added into purple soils for 10 days,50.2%～61.1% of it transformed into residual As,occupying 68%～86% in original soils.For acid purple soil,the As forms were Al-As >Fe-As>Ca-As;for neutral purple soil,they were Ca-As>Al-As>Ca-As>Fe-As>A-As,and for calcic purple soil,they were Ca-As>Al-As>Fe-As>A-As.It is suggested that NH₄Cl could be used as common extractant for different soils,because it slightly affected original As forms in soils,and showed a highly significant correlation (P=0.01) to plant absorption.From pluralistic regressive analysis of plant As content and each As form,Al-As and Fe-As were the main available forms in acid purple soil,but A-As and Ca-As were the most important fractions in neutral and calcic purple soils.The study also showed that H₃BO₃ could restrain the F interference in the operation of As speciation separations.

Maize growth and phosphorousand zinc uptake under different phosphorous supply levels

ZHANG Fucang¹,KANG Shaozhong^1,2,GONG Daozhi¹,LI Zhijun¹

2005, 16(05): 903-906 .

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By the method of solution culture,this paper studied the P and Zn uptake of maize at its growth stages under different P supply levels.The results showed that maize growth reached its maximum at the supply level of 100 μmol P·L^-¹,while the root/shoot ratio was the highest at 0.1 μmol·L^-1 P supply.Increase of P concentration in culture solution promoted the uptake of P,but decreased its utilization rate.The Zn content in root increased with increasing P supply,while that in shoot varied little,which meant that the Zn transportation rate from root to shoot had little change with increasing P concentration.There was a positive correlation between the concentrations of Zn and P in maize seedling roots.

Maize growth and phosphorous-and zinc uptake under different phosphorous supply levels

2005, 16(5): 903-906.

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By the method of solution culture,this paper studied the P and Zn uptake of maize at its growth stages under different P supply levels.The results showed that maize growth reached its maximum at the supply level of 100 μmol P·L^-1,while the root/shoot ratio was the highest at 0.1 μmol·L^-1 P supply.Increase of P concentration in culture solution promoted the uptake of P,but decreased its utilization rate.The Zn content in root increased with increasing P supply,while that in shoot varied little,which meant that the Zn transportation rate from root to shoot had little change with increasing P concentration.There was a positive correlation between the concentrations of Zn and P in maize seedling roots.

Analysis and identification of Liriomyza sativaeattractants from cowpea and kidney bean volatiles

WEI Ming,DENG Xiaojun,DU Jiawei

2005, 16(05): 907-910 .

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In this paper,the volatiles from cowpea and kidney bean,the main host plants of American leafminer Liriomyza sativae,were collected and extracted by a self designed device and solid phase microextraction (SPME) technique,and analyzed by GC-MS.The results showed that the volatiles from the two beans had the same components mainly consisted of 2-hexenal,3-Hexen-1-ol,2-Hexen-1-ol,1-Octen-3-ol,3-Hexenol acetate,α-Ionone and β-Ionone.The lure made of the seven components was attractive to L.sativae in field trapping trials.Detailed analyses indicated that α-Ionone and β-Ionone might play important roles in the searching behavior of L.sativae for host plants.

Analysis and identification of Liriomyza sativae-attractants from cowpea and kidney bean volatiles

2005, 16(5): 907-910.

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In this paper,the volatiles from cowpea and kidney bean,the main host plants of American leafminer Liriomyza sativae,were collected and extracted by a self-designed device and solid phase microextraction (SPME) technique,and analyzed by GC-MS.The results showed that the volatiles from the two beans had the same components mainly consisted of 2-hexenal,3-Hexen-1-ol,2-Hexen-1-ol,1-Octen-3-ol,3-Hexenol acetate,α-Ionone and β-Ionone.The lure made of the seven components was attractive to L.sativae in field trapping trials.Detailed analyses indicated that α-Ionone and β-Ionone might play important roles in the searching behavior of L.sativae for host plants.

Population fluctuation of main pathogens and their antagonistic bacteria in cucumber rhizosphere

LIANG Jiangen¹,ZHANG Bingxin¹,YU Jingquan¹,SHI Jiang²,CHEN Zhenyu¹

2005, 16(05): 911-914 .

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The investigation on the population fluctuation of main pathogens Pythium spp.and Fusarium oxysporum f.sp.cucumerinum in the rhizosphere of four cucumber varieties showed that there was a significant difference in the population number of pathogens for different cucumber varieties and for different growth stages of the same variety,which was in accordance with the regular disease incidence pattern.The population number of Pythium spp. was significantly higher at cucumber creeping stage than at its other growth stages,while that of Fusarium oxysporum f.sp.cucumerinum was the highest at cucumber principal-fruiting stage.There was a closer positive relationship between two test pathogens and their antagonistic bacteria,with the correlation coefficient being 0.95 and 0.81,respectively.

Population fluctuation of main pathogens and their antagonistic bacteria in cucumber rhizosphere

2005, 16(5): 911-914.

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The investigation on the population fluctuation of main pathogens Pythium spp.and Fusarium oxysporum f.sp.cucumerinum in the rhizosphere of four cucumber varieties showed that there was a significant difference in the population number of pathogens for different cucumber varieties and for different growth stages of the same variety,which was in accordance with the regular disease incidence pattern.The population number of Pythium spp.was significantly higher at cucumber creeping stage than at its other growth stages,while that of Fusarium oxysporum f.sp.cucumerinum was the highest at cucumber principal-fruiting stage.There was a closer positive relationship between two test pathogens and their antagonistic bacteria,with the correlation coefficient being 0.95 and 0.81,respectively.

Effects of cinnamic acid on physiological characteristics of Cucumis sativus seedling

WU Fengzhi^1,2,PAN Kai¹,ZHOU Xiuyan¹

2005, 16(05): 915-918 .

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With substrate culture,this paper studied the effects of different concentrations of cinnamic acid on the physiological characteristics of Cucumis sativus seedling.The results showed that 25 μmol·L^-1 of cinnamic acid had an inhibition effect on carotenoids,but a promotion effect on chlorophyll a and b.50 μmol·L^-1 of this compound could significantly inhibit the photosynthetic rate,transpiration rate and root activity (P＜0.05),and this effect was getting stronger when the concentration was higher.150 μmol cinnamic acid·L^-1 had a significant inhibition effect on chlorophyll a and b (P＜0.05).Cinnamic acid had a weak inhibition effect on root activity when its concentration was low（25～50 μmol ·L^-1）,but the effect was significant when the concentration was high (100～150 μmol·L^-1),which became stronger with the longer handling time (P＜0.05).

Effects of cinnamic acid on physiological characteristics of Cucumis sativus seedling

2005, 16(5): 915-918.

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With substrate culture,this paper studied the effects of different concentrations of cinnamic acid on the physiological characteristics of Cucumis sativus seedling.The results showed that 25 μmol·L^-1 of cinnamic acid had an inhibition effect on carotenoids,but a promotion effect on chlorophyll a and b.50 μmol·L^-1 of this compound could significantly inhibit the photosynthetic rate,transpiration rate and root activity (P<0.05),and this effect was getting stronger when the concentration was higher.150 μmol cinnamic acid·L^-1 had a significant inhibition effect on chlorophyll a and b (P<0.05).Cinnamic acid had a weak inhibition effect on root activity when its concentration was low(25～50 μmol ·L^-1),but the effect was significant when the concentration was high (100～150 μmol·L^-1),which became stronger with the longer handling time (P<0.05).

Effects of Colletotrichum higginsianum infection on endogenous hormones in Brassica parachinensis leaves under different nitrogen nutrition

YANG Xian¹,CHEN Xiaoyan²

2005, 16(05): 919-923 .

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This paper studied the effects of Colletotrichum higginsianum infection on the ethylene production and the contents of abscisic acid (ABA) and indole3acetic acid (IAA) in leaves of flowering Chinese cabbage (Brassica parachinensis) under six levels of nitrogen (N) nutrition,and their relations to disease-resistance.The results showed that the ethylene production in all N treatments had a mono-peak curve change,and reached the maximum 4～6 days after inoculation.In comparing with high N or non-N treatment,medium or low N treatment could inhibit ethylene production and ABA synthesis,and keep ethylene and ABA stable in Colletotrichum higginsianuminoculated plants.The IAA content in medium or low N treatment increased gradually, while that in high N or non-N treatment had a mono-peak curve change,and reached the maximum 4～6 days after inoculation.The IAA content in medium or low N treatment increased more with inoculation time,indicating that there was a close relationship among N nutrition,endogenous hormones and anthracnose.It is important for plants' diseaseresistance to keep the balance of endogenous hormones.

Effects of Colletotrichum higginsianum infection on endogenous hormones in Brassica parachinensis leaves under different nitrogen nutrition

2005, 16(5): 919-923.

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This paper studied the effects of Colletotrichum higginsianum infection on the ethylene production and the contents of abscisic acid (ABA) and indole-3-acetic acid (IAA) in leaves of flowering Chinese cabbage (Brassica parachinensis) under six levels of nitrogen (N) nutrition,and their relations to disease-resistance.The results showed that the ethylene production in all N treatments had a mono-peak curve change,and reached the maximum 4～6 days after inoculation.In comparing with high N or non-N treatment,medium or low N treatment could inhibit ethylene production and ABA synthesis,and keep ethylene and ABA stable in Colletotrichum higginsianum-inoculated plants.The IAA content in medium or low N treatment increased gradually,while that in high N or non-N treatment had a mono-peak curve change,and reached the maximum 4～6 days after inoculation.The IAA content in medium or low N treatment increased more with inoculation time,indicating that there was a close relationship among N nutrition,endogenous hormones and anthracnose.It is important for plants' disease-resistance to keep the balance of endogenous hormones.

Effects of free-air CO₂ enrichment (FACE) on phosphorus nutrition of Oryzasativa at its different growth stages

YANG Lianxin¹,YANG Hongjian¹,HUANG Jianye¹,WANG Yulong¹,ZHU Jianguo²,LIU Hongjiang¹,DONG Guichun¹,SHAN Yuhua¹

2005, 16(05): 924-928 .

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Using free-air CO₂enrichment (FACE) platform and under different nitrogen supply level,this paper studied the phosphorus nutrition of Oryza sativa at its different growth stages.The CO₂ concentration of FACE platform was 200 μmol·mol^-1 more than that in ambient air,and the nitrogen supply levels were 150 kg·hm^-2,250 kg·hm^-2 and 280 kg·hm^-2.The results showed that during rice growth period,FACE significantly increased the phosphorus content of rice plant and its phosphorus uptake by 3.9%～20.6% and 28.9%～71.4%,respectively.Before heading,FACE had little effect on the phosphorous accumulation in leaf or stake,but after heading,it made the proportion of phosphorus accumulation in reproductive organ decreased by 9.8%～26.3% and that in vegetative organ increased by 2.2%～23.9% at 0.01 or 0.05 significant level.Under FACE treatment,the phosphorus use efficiency for biomass production (PUEp) at different growth stages,the phosphorus use efficiency for grain output (PUEg),and the phosphorus harvest index (PHI) were decreased by 3.7%～16.6%,6.5%～15.5%,5.4%～9.0%,respectively.Nitrogen supply level and its interaction with FACE had less effect on the phosphorus nutrition of rice at its different growth stages.

Effects of free-air CO₂ enrichment (FACE) on phosphorus nutrition of Oryza sativa at its different growth stages

2005, 16(5): 924-928.

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Using free-air CO₂ enrichment (FACE) platform and under different nitrogen supply level,this paper studied the phosphorus nutrition of Oryza sativa at its different growth stages.The CO₂ concentration of FACE platform was 200 μmol·mol -1 more than that in ambient air,and the nitrogen supply levels were 150 kg·hm^-2,250 kg·hm^-2 and 280 kg·hm^-2.The results showed that during rice growth period,FACE significantly increased the phosphorus content of rice plant and its phosphorus uptake by 3.9%～20.6% and 28.9%～71.4%,respectively.Before heading,FACE had little effect on the phosphorous accumulation in leaf or stake,but after heading,it made the proportion of phosphorus accumulation in reproductive organ decreased by 9.8%～26.3% and that in vegetative organ increased by 2.2%～23.9% at 0.01 or 0.05 significant level.Under FACE treatment,the phosphorus use efficiency for biomass production (PUEp) at different growth stages,the phosphorus use efficiency for grain output (PUEg),and the phosphorus harvest index (PHI) were decreased by 3.7%～16.6%,6.5%～15.5%,5.4%～9.0%,respectively.Nitrogen supply level and its interaction with FACE had less effect on the phosphorus nutrition of rice at its different growth stages.

Concentrations of metallic elements,N and S in Sabina chinensis cv.pyramidalis leaves along urban-rural roadways of Nanjing city

YIN Yunlong¹,LUO Yongming¹,ZHANG Taolin¹,HE Jianfeng²,XU Jianhua²

2005, 16(05): 929-932 .

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This paper measured the concentrations of metallic elements,N and S in soils and Sabina chinensis cv.pyramidalis leaves along the urban-rural roadways (urban trunk roads,belt highway,and suburban roads) of Nanjing city,with botanical garden as un-traffic impacted reference site,and discussed the transfer of test elements among atmosphere,plant and soil,as well as the impact of traffic- related pollution.The results showed that the concentrations of Al,Fe,Mo,Zn,Cd,Pb,As and Cr in Sabina chinensis leaves were significantly higher along urbanrural roadways than at reference site,being most remarkable for Al,Fe,Mo and Zn.The positive correlations between soil and Sabina chinensis leaf Fe,Zn and As concentrations in road environment indicated that Sabina chinensis might be a good indicator plant of soil Fe,Zn and As.The correlations between soil and plant leaf Al,Mo,Cu,Pb,Cd and Cr concentrations were not remarkable,and thus,their high concentrations in Sabina chinensis leaf in road environment might be caused by air pollution.The concentrations of N and S in Sabina chinensis leaf were higher along urban trunk roads and belt highway than at reference site,while those along suburban roads were similar to the reference.There was a negative correlation between soil and plant leaf N,and a positive correlation between soil and plant leaf S.The N content in roadside soil was lower,while the S content was higher than the reference,indicating that the higher Sabina chinensis leaf N content in road environment might be caused by the NOx from exhaust gas emission,and the higher leaf S content should be come from soil.

Concentrations of metallic elements,N and S in Sabina chinensis cvpyramidalis leaves along urban-rural roadways of Nanjing city

2005, 16(5): 929-932.

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This paper measured the concentrations of metallic elements,N and S in soils and Sabina chinensis cv.pyramidalis leaves along the urban-rural roadways (urban trunk roads,belt highway,and suburban roads) of Nanjing city,with botanical garden as un-traffic impacted reference site,and discussed the transfer of test elements among atmosphere,plant and soil,as well as the impact of traffic- related pollution.The results showed that the concentrations of Al,Fe,Mo,Zn,Cd,Pb,As and Cr in Sabina chinensis leaves were significantly higher along urban-rural roadways than at reference site,being most remarkable for Al,Fe,Mo and Zn.The positive correlations between soil and Sabina chinensis leaf Fe,Zn and As concentrations in road environment indicated that Sabina chinensis might be a good indicator plant of soil Fe,Zn and As.The correlations between soil and plant leaf Al,Mo,Cu,Pb,Cd and Cr concentrations were not remarkable,and thus,their high concentrations in Sabina chinensis leaf in road environment might be caused by air pollution.The concentrations of N and S in Sabina chinensis leaf were higher along urban trunk roads and belt highway than at reference site,while those along suburban roads were similar to the reference.There was a negative correlation between soil and plant leaf N,and a positive correlation between soil and plant leaf S.The N content in roadside soil was lower,while the S content was higher than the reference,indicating that the higher Sabina chinensis leaf N content in road environment might be caused by the NO_x from exhaust gas emission,and the higher leaf S content should be come from soil.

Responses of antioxidation system of Cynodon dactylon to recirculated landfill leachate irrigation

WANG Ruyi,HE Pinjing,SHAO Liming,ZHANG Bin,LI Guojian

2005, 16(05): 933-938 .

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With pot experiment,this paper studied the membrane lipid peroxidation and the variations of antioxidation system in Cynodon dactylon under recirculated landfill leachate irrigation.The results showed that when irrigated with low dilution ratio (<25%) leachate,the chlorophyll a/b ratio increased with increasing dilution ratio,cell membrane permeability and MDA and H₂O₂contents were in adverse,and membrane lipid peroxidation was relatively weak.However,with the increasing leachate dilution ratio (＞25%),there existed an obvious negative effect onCynodon dactylon,i.e.,the chlorophyll a/b ratio decreased,while cell membrane permeability and MDA and H₂O₂ contents increased,which meant that the membrane lipid peroxidation was accelerated.The contents of antioxidants AsA,GSH and Car also showed the similar trend,i.e.,they increased with increasing leachate dilution ratio when irrigated with low dilution ratio leachate,but decreased under medium or high dilution ratio leachate irrigation.Among three test anti-oxidative enzymes,SOD and POD activities showed a similar change to test antioxidants, and POD activity was more sensitive,while CAT activity was on the contrary.The contents of test antioxidants and the activities of SOD and POD were negatively and significantly correlated to MDA content,indicating that they might play an important role in preventing Cynodon dactylon from cell membrane lipid peroxdation.

Responses of antioxidation system of Cynodon dactylon to recirculated landfill leachate irrigation

2005, 16(5): 933-938.

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With pot experiment,this paper studied the membrane lipid peroxidation and the variations of antioxidation system in Cynodon dactylon under recirculated landfill leachate irrigation.The results showed that when irrigated with low dilution ratio (<25%) leachate,the chlorophyll a/b ratio increased with increasing dilution ratio,cell membrane permeability and MDA and H₂O₂ contents were in adverse,and membrane lipid peroxidation was relatively weak.However,with the increasing leachate dilution ratio (>25%),there existed an obvious negative effect on Cynodon dactylon,i.e.,the chlorophyll a/b ratio decreased,while cell membrane permeability and MDA and H₂O₂ contents increased,which meant that the membrane lipid peroxidation was accelerated.The contents of antioxidants AsA,GSH and Car also showed the similar trend,i.e.,they increased with increasing leachate dilution ratio when irrigated with low dilution ratio leachate,but decreased under medium or high dilution ratio leachate irrigation.Among three test anti-oxidative enzymes,SOD and POD activities showed a similar change to test antioxidants,and POD activity was more sensitive,while CAT activity was on the contrary.The contents of test antioxidants and the activities of SOD and POD were negatively and significantly correlated to MDA content,indicating that they might play an important role in preventing Cynodon dactylon from cell membrane lipid peroxdation.

Spatial variation of microbial properties in a creosote-contaminated soil

YANG Xiuhong¹,LI Shiyu¹,Gran Bengtsson²,Niklas Trneman²

2005, 16(05): 939-944 .

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By the methods of geostatistics,this paper studied the spatial variation of microbial biomass,microbial community structure and microbial activity in a creosote-contaminated soil.The microbial biomass was indicated by the total amount of 26 examined phospholipid fatty acids (totPLFA),the microbial community structure was characterized by the first two principal components (PC1 and PC2) of the PLFA patterns through subjecting the PLFAs to principal component analysis,and the total amount of CO₂-C respired (Cre) during incubation was used to describe the soil microbial activity.The results showed that most of the variables exhibited various degrees of spatial autocorrelation, and spherical models with nugget could fit their semivariograms. The estimated spatial dependence distances of the variables varied from 2.50 to 16.60 m.The PLFA PC1,totPLFA and Cre displayed relatively high spatial dependences,their relative structural variance,i.e.,the proportion of total variance that can be attributed to the spatial autocorrelation, being 82.3%，79.6% and 64.7%,respectively,while PLFA PC2 was not spatially autocorrelated.The kriged maps showed that there were several hot spots with relatively high microbial biomass and high microbial activity located in the study site.Gram- negative bacteria characterized by PLFAs 16:1ω7t,cy17:0,18:1ω7 and cy19:0 were the dominant community in these hot spots.The concentration and spatial distribution of polycyclic aromatic hydrocarbons as the main contaminants in the soil could be one of the important factors affecting the spatial variation of soil microbial properties.

Spatial variation of microbial properties in a creosote-contaminated soil

2005, 16(5): 939-944.

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By the methods of geostatistics,this paper studied the spatial variation of microbial biomass,microbial community structure and microbial activity in a creosote-contaminated soil.The microbial biomass was indicated by the total amount of 26 examined phospholipid fatty acids (totPLFA),the microbial community structure was characterized by the first two principal components (PC1 and PC2) of the PLFA patterns through subjecting the PLFAs to principal component analysis,and the total amount of CO₂-C respired (C_re) during incubation was used to describe the soil microbial activity.The results showed that most of the variables exhibited various degrees of spatial autocorrelation,and spherical models with nugget could fit their semivariograms.The estimated spatial dependence distances of the variables varied from 2.50 to 16.60 m.The PLFA PC1,totPLFA and C re displayed relatively high spatial dependences,their relative structural variance,i.e.,the proportion of total variance that can be attributed to the spatial autocorrelation,being 82.3%,79.6% and 64.7%,respectively,while PLFA PC2 was not spatially autocorrelated.The kriged maps showed that there were several hot spots with relatively high microbial biomass and high microbial activity located in the study site.Gram- negative bacteria characterized by PLFAs 16:1^ω7t,cy17:0,18:1^ω7 and cy19:0 were the dominant community in these hot spots.The concentration and spatial distribution of polycyclic aromatic hydrocarbons as the main contaminants in the soil could be one of the important factors affecting the spatial variation of soil microbial properties.

Phytoremediation of mercury and cadmium polluted wetland by Arundo donax

HAN Zhiping¹,HU Xiaobin¹,HU Zhenghai²

2005, 16(05): 945-950 .

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With a pot culture of simulated mercury (Hg) and cadmium (Cd)polluted wetland,this paper studied the capability of Arundo donax in accumulating these heavy metals,and their distribution in the plant.The results showed that after grown in a 101 mg·kg^-1 Hgpolluted wetland for 8 months,the Hg-concentrating capability of Arundo donaxwas in order of root> stem> leaf, and the Hg concentration in its aboveground parts was 200±20 mg·kg^-1(DW); while in the case of 115 mg·kg^-1 Cdpollution,the Cd-concentrating capability was in order of leaf>root>stem,and the Cd concentration in leaf was 160±26 mg·kg^-1(DW).The heavy metals concentration in Arundo donax organs increased with its growth time,being 30%～50% higher for 8 months than for 4 months.The BCF (Bio-concentration factor) decreased with increasing heavy metals concentration.In polluted wetland,the BCFs of Hg by the leaf and stem were 1.9 and 2.1,and those of Cd were 1.5 and 0.3, respectively; while in unpolluted wetland,the concentration of Hg and Cd was 6.8 and 8.5mg·kg^-1,the BCFs of Hg by the leaf and stem were 6.8 and 12.2, and those of Cd were 7.0 and 2.7,respectively.It was indicated that Arundo donax not only had the characters of large biomass,exuberant root,and good adaptability,but also exhibited high tolerance and concentrating capability to Cd and Hg.

Phytoremediation of mercury and cadmium polluted wetland by Arundo donax

2005, 16(5): 945-950.

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With a pot culture of simulated mercury (Hg) and cadmium (Cd)-polluted wetland,this paper studied the capability of Arundo donax in accumulating these heavy metals,and their distribution in the plant.The results showed that after grown in a 101 mg·kg^-1 Hg-polluted wetland for 8 months,the Hg-concentrating capability of Arundo donax was in order of root>stem>leaf,and the Hg concentration in its aboveground parts was 200±20 mg·kg^-1(DW); while in the case of 115 mg·kg^-1 Cd-pollution,the Cd-concentrating capability was in order of leaf>root>stem,and the Cd concentration in leaf was 160±26 mg·kg^-1(DW).The heavy metals concentration in Arundo donax organs increased with its growth time,being 30%～50% higher for 8 months than for 4 months.The BCF (Bio-concentration factor) decreased with increasing heavy metals concentration.In polluted wetland,the BCFs of Hg by the leaf and stem were 1.9 and 2.1,and those of Cd were 1.5 and 0.3,respectively; while in unpolluted wetland,the concentration of Hg and Cd was 6.8 and 8.5mg·kg^-1,the BCFs of Hg by the leaf and stem were 6.8 and 12.2,and those of Cd were 7.0 and 2.7,respectively.It was indicated that Arundo donax not only had the characters of large biomass,exuberant root,and good adaptability,but also exhibited high tolerance and concentrating capability to Cd and Hg.

Effects of simulated nitrogen deposition on weeds growth and nitrogen uptake

JIANG Qiqing¹,TANG Jianjun¹,CHEN Xin^1,2,CHEN Jing¹,YANG Ruyi¹,Hu S²

2005, 16(05): 951-955 .

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In this paper,a greenhouse experiment was conducted to study the responses of different functional groups of weeds to simulated nitrogen deposition (4.0 g N· m^-2·yr^-1).Native weed species-Poa annua,Lolium perenne,Avena fatua,Medicago lupulina,Trifolium repens,Plantago virginica,Veronica didyma,Echinochloa crusgalli var.mitis,Eleusine indica and Amaranthus spinosus in orchard ecosystem were used as test materials,and their above-and underground biomass and nitrogen uptake were measured.The results showed that under simulated N deposition,the total biomass,shoot biomass and root biomass of all weed species tended to increase,while the total biomass was differed for different functional groups of weeds.The biomass of C₄grass,C₃ legumes and C₃ grass was significantly increased under N deposition,while that of C₃ and C₄ forbs was not significantly impacted.The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition,but that of Poa annu,Lolium perenne,Medicago lupulina,Trifolium repensand Amarathus spinosus was not impacted significantly.N deposition had no significant effect on plant N concentration,but significantly enhanced the N uptake of all test weed species except Amarathus spinosus,Poa annua and Veronica didyma.It was suggested that the further increase of N deposition might speed up the changes of the community structure of weed species due to their different responses to N deposition.

Effects of simulated nitrogen deposition on weeds growth and nitrogen uptake

2005, 16(5): 951-955.

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In this paper,a greenhouse experiment was conducted to study the responses of different functional groups of weeds to simulated nitrogen deposition (4.0 g N穖^-2穣r^-1).Native weed species Poa annua,Lolium perenne,Avena fatua,Medicago lupulina,Trifolium repens,Plantago virginica,Veronica didyma,Echinochloa crusgalli var.mitis,Eleusine indica and Amaranthus spinosus in orchard ecosystem were used as test materials,and their above-and underground biomass and nitrogen uptake were measured.The results showed that under simulated N deposition,the total biomass,shoot biomass and root biomass of all weed species tended to increase,while the total biomass was differed for different functional groups of weeds.The biomass of C₄ grass,C₃ legumes and C₃ grass was significantly increased under N deposition,while that of C₃ and C₄ forbs was not significantly impacted.The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition,but that of Poa annu,Lolium perenne,Medicago lupulina,Trifolium repens and Amarathus spinosus was not impacted significantly.N deposition had no significant effect on plant N concentration,but significantly enhanced the N uptake of all test weed species except Amarathus spinosus,Poa annua and Veronica didyma.It was suggested that the further increase of N deposition might speed up the changes of the community structure of weed species due to their different responses to N deposition.

Extraction method of soil microbial DNA for molecular ecology study

ZHANG Yuguang^1,2,LI Diqiang¹,WANG Huimin²,XIAO Qiming²

2005, 16(05): 956-960 .

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In environmental microbiology,molecular ecology study has been widely concerned in the world,while high quality DNA is the basis of the study.In our study,soil microbial DNA was extracted by the methods of SDS lysis and denaturant plus SDS lysis,and purified with gel electrophoresis plus minicolumn and double minicolumn methods.The results showed that denaturant plus SDS lysis could extract DNA more efficiently,and gel electrophoresis plus minicolumn could help to obtain purer DNA that was available in amplifying its 16S rDNA and functional genes by PCR. Therefore,denaturant plus SDS lysis could be an efficient and reliable method to extract DNA in molecular ecology studies.

Extraction method of soil microbial DNA for molecular ecology study

2005, 16(5): 956-960.

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In environmental microbiology,molecular ecology study has been widely concerned in the world,while high quality DNA is the basis of the study.In our study,soil microbial DNA was extracted by the methods of SDS lysis and denaturant plus SDS lysis,and purified with gel electrophoresis plus minicolumn and double minicolumn methods.The results showed that denaturant plus SDS lysis could extract DNA more efficiently,and gel electrophoresis plus minicolumn could help to obtain purer DNA that was available in amplifying its 16S rDNA and functional genes by PCR.Therefore,denaturant plus SDS lysis could be an efficient and reliable method to extract DNA in molecular ecology studies.

Carrying capacity of shellfish culture in Dadeng Island sea area of Xiamen

LU Zhenbin,DU Qi,FANG Minjie,QIAN Xiaoming,CAI Qinghai,XU Cuiya

2005, 16(05): 961-966 .

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To fully and rationally exploit local living marine resources while have a sustainable,efficient and healthy development of shellfish culture in the Dadeng Island sea area of Xiamen,this paper determined and analyzed the related model parameters of this area,including chlorophyll a,primary productivity,phytoplankton organic carbon content,wild filter feeder yields in subtidal and intertidal zones and suspension culture area,cultured shellfish filtration rate and organic carbon content,shellfish's total weight to fresh meat ratio,and adopted the Nutrient Dynamic Model and Coastal Waters' Energy Flow Analysis Model to estimate the ecological capacity of shellfish in this area,from which,the wild filter feeder yields were deducted for estimating shellfish carrying capacity.The model established by Fang Jianguang was also used to estimate the shellfish carrying capacity.Statistics analysis was used to estimate the suitable culture area of shellfish and other species,aiming at limiting local shellfish culture and optimizing the culture of various species mollusks.According to the estimation of the three models,the shellfish carrying capacity in this area should be 35 248～39 990 tons,with an average of 37 488 tons,and 140 008×10⁴～158 850×10⁴ individuals,averaging 148 903×10⁴.The theoretically suitable culture area was 2 145 hm²,1 900 hm² for Ostreidae,81 hm² for razor clam (Sinonovacula constricta),20 hm² for blood clam (Tegillarca granosa),and 144 hm² for musculus (Musculus senhousei).In 2000,the actual culture area of shellfish and other species in the waters around Dadeng surpassed the estimated suitable culture area.It is proposed that some measures should be taken to reduce the verexploited area.

Carrying capacity of shellfish culture in Dadeng Island sea area of Xiamen

2005, 16(5): 961-966.

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To fully and rationally exploit local living marine resources while have a sustainable,efficient and healthy development of shellfish culture in the Dadeng Island sea area of Xiamen,this paper determined and analyzed the related model parameters of this area,including chlorophyll a,primary productivity,phytoplankton organic carbon content,wild filter feeder yields in subtidal and intertidal zones and suspension culture area,cultured shellfish filtration rate and organic carbon content,shellfish's total weight to fresh meat ratio,and adopted the Nutrient Dynamic Model and Coastal Waters' Energy Flow Analysis Model to estimate the ecological capacity of shellfish in this area,from which,the wild filter feeder yields were deducted for estimating shellfish carrying capacity.The model established by Fang Jianguang was also used to estimate the shellfish carrying capacity.Statistics analysis was used to estimate the suitable culture area of shellfish and other species,aiming at limiting local shellfish culture and optimizing the culture of various species mollusks.According to the estimation of the three models,the shellfish carrying capacity in this area should be 35 248～39 990 tons,with an average of 37 488 tons,and 140 008×10⁴～158 850×10⁴ individuals,averaging 148 903×10⁴.The theoretically suitable culture area was 2 145 hm²,1 900 hm² for Ostreidae,81 hm² for razor clam (Sinonovacula constricta),20 hm² for blood clam (Tegillarca granosa),and 144 hm² for musculus (Musculus senhousei).In 2000,the actual culture area of shellfish and other species in the waters around Dadeng surpassed the estimated suitable culture area.It is proposed that some measures should be taken to reduce the overexploited area.

Effects of culture condition on fatty acids in Pseudomonas sp

YE Fangting¹,YAN Xiaojun¹,ZHENG Li^2，3,XU Jilin¹,CHEN Haimin¹

2005, 16(05): 967-970 .

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The investigation on the growth of Pseudomonas sp.and the dynamics of its fatty acids under various culture conditions indicated that the optimum temperature for its growth was 30 ℃,and the best carbon source was starch.13 kinds of fatty acids were detected,among which,c16:1(n₇),c15:0, c16:0,c17:0,c18:1(n₆),c18:1(n₉),9,10cpc17:0 and iso9,10cpc17:0 were the major ones.When cultured at 30 ℃,the relative content of unsaturated fatty acids decreased significantly.Carbon source in the media was the crucial factor affecting the contents of odd- and cyclopropane fatty acids.Cluster analysis revealed that temperature had a more obvious effect than carbon source.

Effects of culture condition on fatty acids in Pseudomonas sp

2005, 16(5): 967-970.

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The investigation on the growth of Pseudomonas sp.and the dynamics of its fatty acids under various culture conditions indicated that the optimum temperature for its growth was 30 ℃,and the best carbon source was starch.13 kinds of fatty acids were detected,among which,c16:1(n-7),c15:0,c16:0,c17:0,c18:1(n-6),c18:1(n-9),9,10-cp-c17:0 and iso9,10-cp-c17:0 were the major ones.When cultured at 30 ℃,the relative content of unsaturated fatty acids decreased significantly.Carbon source in the media was the crucial factor affecting the contents of odd- and cyclopropane fatty acids.Cluster analysis revealed that temperature had a more obvious effect than carbon source.

Roles of calcium in stresstolerance of plants and its ecological significance

JIANG Tinghui,ZHAN Xinhua,XU Yangchun,ZHOU Lixiang,ZONG Lianggang

2005, 16(05): 971-976 .

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Calcium loss from soil has dramatically increased for decades due to the increase of nitrogen input and/or the extension of acid rain,while calcium input into soil has declined substantially for the replacement of superphosphate by ammonium phosphate in fertilization,which intensified the imbalance of calcium input and output in agro-ecosystems,and needed to be solved in the near future for the sustainability of agriculture in such a country like China where the arable land resource is very limited.In recent years,the intensified soil acidification is mainly attributed to the root proton secretion stimulated by fertilization,and the nitrogen input from precipitation near industrialized regions promotes plant growth but results in other nutrients deficiency,which in turn acidifies soil and causes tree death.One of the most important mechanisms of saline soil bioremediation by sesbania is the activation of soil calcium by sesbania's proton secretion and the increase of soil calcium supply for subsequent crops.The present paper summarized the roles of calcium in plant tolerance to the stresses like acidosis,toxic metals,osmosis,ammonium toxicity,drought,extreme temperature (cold or heat shock),anoxia and pathogen infection,and the measures for maintaining soil calcium fertility.It was suggested that the production of ammonium phosphate should not be a pursued target for China's phosphorus fertilizer industry,and the roles of calcium in plant growth should be taken into account in fertilization experimental designs to make the experiments more accurate.

Roles of calcium in stress-tolerance of plants and its ecological significance

2005, 16(5): 971-976.

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Calcium loss from soil has dramatically increased for decades due to the increase of nitrogen input and/or the extension of acid rain,while calcium input into soil has declined substantially for the replacement of superphosphate by ammonium phosphate in fertilization,which intensified the imbalance of calcium input and output in agro-ecosystems,and needed to be solved in the near future for the sustainability of agriculture in such a country like China where the arable land resource is very limited.In recent years,the intensified soil acidification is mainly attributed to the root proton secretion stimulated by fertilization,and the nitrogen input from precipitation near industrialized regions promotes plant growth but results in other nutrients deficiency,which in turn acidifies soil and causes tree death.One of the most important mechanisms of saline soil bioremediation by sesbania is the activation of soil calcium by sesbania's proton secretion and the increase of soil calcium supply for subsequent crops.The present paper summarized the roles of calcium in plant tolerance to the stresses like acidosis,toxic metals,osmosis,ammonium toxicity,drought,extreme temperature (cold or heat shock),anoxia and pathogen infection,and the measures for maintaining soil calcium fertility.It was suggested that the production of ammonium phosphate should not be a pursued target for China's phosphorus fertilizer industry,and the roles of calcium in plant growth should be taken into account in fertilization experimental designs to make the experiments more accurate.

A landscape ecological approach for urban non-point source pollution control

GUO Qinghai,MA Keming,ZHAO Jingzhu,YANG Liu,YIN Chengqing

2005, 16(05): 977-981 .

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Urban non-point source pollution is a new problem appeared with the speeding development of urbanization.The particularity of urban land use and the increase of impervious surface area make urban non-point source pollution differ from agricultural non-point source pollution,and more difficult to control.Best Management Practices (BMPs) are the effective practices commonly applied in controlling urban non-point source pollution,mainly adopting local repairing practices to control the pollutants in surface runoff. Because of the close relationship between urban land use patterns and non-point source pollution,it would be rational to combine the landscape ecological planning with local BMPs to control the urban non-point source pollution,which needs,firstly,analyzing and evaluating the influence of landscape structure on water-bodies,pollution sources and pollutant removal processes to define the relationships between landscape spatial pattern and non-point source pollution and to decide the key polluted fields,and secondly, adjusting inherent landscape structures or/and joining new landscape factors to form new landscape pattern,and combining landscape planning and management through applying BMPs into planning to improve urban landscape heterogeneity and to control urban non-point source pollution.

A landscape ecological approach for urban non-point source pollution control

2005, 16(5): 977-981.

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Urban non-point source pollution is a new problem appeared with the speeding development of urbanization.The particularity of urban land use and the increase of impervious surface area make urban non-point source pollution differ from agricultural non-point source pollution,and more difficult to control.Best Management Practices (BMPs) are the effective practices commonly applied in controlling urban non-point source pollution,mainly adopting local repairing practices to control the pollutants in surface runoff.Because of the close relationship between urban land use patterns and non-point source pollution,it would be rational to combine the landscape ecological planning with local BMPs to control the urban non-point source pollution,which needs,firstly,analyzing and evaluating the influence of landscape structure on water-bodies,pollution sources and pollutant removal processes to define the relationships between landscape spatial pattern and non-point source pollution and to decide the key polluted fields,and secondly,adjusting inherent landscape structures or/and joining new landscape factors to form new landscape pattern,and combining landscape planning and management through applying BMPs into planning to improve urban landscape heterogeneity and to control urban non-point source pollution.

Effects of Pb²⁺ and Cd²⁺ pollution on physiological characteristics of Thuidium cymbifolium

WEI Haiying,Fang Yanming,YIN Zengfang

2005, 16(05): 982-984 .

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This paper dealt with the effects of Pb²⁺,Cd²⁺ and their combined pollution on the contents of chlorophyll,potassium and calcium in Thuidium cymbifolium. The results showed that except at 0.1 mg Cd²⁺·L^-1,the chlorophyll content decreased with increasing Pb²⁺ and Cd²⁺ concentrations,which was 18% of the control at 100 mg Cd²⁺·L^-1,and decreased by 48.6% at 200 mg Pb²⁺·L^-1.The potassium and calcium contents also decreased with increasing pollutants concentrations,being decreased by 61.1% at 100 mg Cd²⁺·L^-1. Cd²⁺ had a stronger toxicity than Pb²⁺,and the toxicity of their combined pollution was stronger than that of each pollutant.Pb²⁺ could increase the toxicity of Cd²⁺.

Effects of Pb²⁺ and Cd²⁺ pollution on physiological characteristics of Thuidium cymbifolium

2005, 16(5): 982-984.

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This paper dealt with the effects of ²⁺,²⁺ and their combined pollution on the contents of chlorophyll,potassium and calcium in Thuidium cymbifolium.The results showed that except at 0.1 mg ²⁺稬^-1,the chlorophyll content decreased with increasing ²⁺ and ²⁺ concentrations,which was 18% of the control at 100 mg ²⁺稬^-1,and decreased by 48.6% at 200 mg ²⁺稬^-1.The potassium and calcium contents also decreased with increasing pollutants concentrations,being decreased by 61.1% at 100 mg ²⁺稬^-1.²⁺ had a stronger toxicity than ²⁺,and the toxicity of their combined pollution was stronger than that of each pollutant.²⁺ could increase the toxicity of ²⁺.

A conjecture on the fertilizer recovery measurement by field experiment

SHEN Shanmin

2005, 16(5): 781-782.

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The measurement of fertilizer recovery either by isotope tracer technique or by field experiment with plots fertilized and unfertilized, both were suspected unreliable and reasons were discussed. Based on some reasonable presumptions, an alternative way of estimating fertilizer recovery by field trials was proposed in this paper, but further examination on it's reliability is needed.

Litterfall in main forest ecosystems of Northeast China

LI Xuefeng, HAN Shijie, LI Yuwen, Hou Bingzhu, Li Xuelian

2005, 16(5): 783-788.

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A three-year investigation on the litterfall of 15 forests in 4 different regions of Northeast China showed that the annual litterfall had a significant difference among forest types in the same region,but no significant difference was found between years.In the litterfall,leaf occupied 70% and more,while branch,flower and fruit were less than 20%.The branch production correlated positively with leaf production,and the correlation coefficient was 0.82.According to the investigation of 5 forest types in Changbai Mountain,the litterfall was 2.62～9.14 times higher in autumn and winter than in spring and summer.The peak of leaf-fall appeared in autumn,while that of branch and others withered evenly during a year.The litterfall of same forest type decreased with increasing latitude,and the relationships of the total and birch litterfall with latitude were established.Both the total and the birch litterfall were positively related to annual mean temperature,with the correlation coefficient 0.95 and 0.91,respectively.

Plantation stocks and their affecting factors in western Liaoning Province

WANG Jian, LIU Zuoxin, CAI Congguang

2005, 16(5): 789-794.

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Employing real-site investigation and data analysis methods,this paper analyzed the distribution of plantation stocks and its affecting factors in western Liaoning Province.The results showed that the average plantation stock of western Liaoning was 49.08 m 3穐m^-2,which has been improved obviously since 1949.At the time of the third forest resource investigation,the plantation stock increased 20.19 m 3穐m^-2,5.16 times higher than that of the first forest resource investigation.But,the general plantation stock of western Liaoning was still at a rather lower level,with only a 63.5% increase of the whole province and 51.1% of the national average plantation stock at the same period.The difference of plantation stock among cities in western Liaoning was observable,that even reached 68.47 m 3穐m^-2.In general,the proportion of young forest was too high,reached to 49% of the total plantation,while the stock of mature forest was much lower,only 38% of the national average level.The plantation stock of national property was only 55.1% and 32.3% of the personal and collective property,respectively.Moreover,the plantation stock of timber forest was 36.4% lower than that of windbreak.Besides climatic factors,simple plantation structure,few forest tree species,and poor plantation management were the main causes of the low plantation stock.

Genetic diversity of Hepatacodium miconioides natural populations in Zhejiang Province

LI Junmin, JIN Zexin

2005, 16(5): 795-800.

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Hepatacodium miconioides is the Class II protected plant species in China.This paper studied the genetic diversity and differentiation of its nine natural populations in Zhejiang Province by using random amplified polymorphic DNA (RAPD) technique.Twelve random primers were selected in the amplification,and 164 repetitive loci were produced.The percentage of polymorphic loci in each H.miconioides population ranged from 14.60% to 27.44%,with an average of 20.73%.Among the test populations,Kuochangshan population had the highest percentage of polymorphic loci,Simingshan population took the second place,and Guanyinping population had the lowest one.As estimated by Shannon index,the genetic diversity within H.miconioides populations accounted for 27.28% of the total genetic diversity,while that among H.miconioides populations accounted for 72.72%.The genetic differentiation among H.miconioides populations as estimated by Nei index was 0.7157.The genetic differentiation estimated by Nei index was generally consistent with that estimated by Shannon index,i.e.,the genetic differentiation among populations was relatively high,but that within populations was relatively low.The gene flow among H.miconioides populations was relatively low (0.1987),and the genetic similarity ranged from 0.6557 to 0.8119,with an average of 0.7306.The highest genetic distance among populations was 0.4229,while the lowest one was 0.2083.All the results showed that there was a distinct genetic differentiation among H.miconioides populations.The genetic distance matrix of nine test populations was calculated by using the method,and the clustering analysis was made by using the unweighted pair group method with arithmetic mean (UPGMA).The cluster analysis suggested that the nine populations of H.miconioides in Zhejiang Province could be divided into two groups,i.e.,eastern Zhejiang group and western Zhejiang group.

Effects of polyethylene glycol (PEG)-simulated drought stress on Pinus sylvestris varmongolica seed germination on sandy land

ZHU Jiaojun, LI Zhihui, KANG Hongzhang, FAN Yezhan

2005, 16(5): 801-804.

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With introduced sandy land Mongolian pine (Pinus sylvestris var.mongolica) seeds as test material,this paper studied the effects of polyethylene glycol (PEG)-simulated drought stress on their germination.The results showed that PEG could retard the germination of stressed seeds,and the germination rate,germination index,and germination potential were all decreased with increasing PEG concentration.The seeds treated with 30% PEG (about -1.20 MPa water potential) could not germinate at all throughout the experiment period,suggesting that 30% PEG or -1.20 MPa water potential was the threshold for the germination of Mongolian pine seeds.Under 10% PEG stress (about -0.20 MPa water potential),the lengths of radicle and hypocotyl were shorter,illustrating their growth be more sensitive to PEG-simulated drought stress,while the radicle / hypocotyl ratio was increased with increasing PEG concentration,indicating that Mongolian pine seeds had a stronger resistance to drought stress after germination.Drought stress might be a possible cause that inhibited the natural regeneration of Mongolian pine on sandy land.

Effects of exogenous nitric oxide on drought-resistance of poplar

WANG Miao, LI Qiurong, FU Shilei, XIAO Dongmei, DONG Baili

2005, 16(5): 805-810.

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This paper studied the effects of NO donor sodium nitroprusside (SNP) on the photosynthesis and active oxygen-scavenging enzyme activities of poplar leaves under drought stress.The results showed that SNP had a remarkable positive effect on leaf water content.When the SNP level was >500 μmol·L^-1,no significant difference in leaf water content was found between SNP treatments.SNP could increase photosynthesis rate,photochemical efficiency of PSII (F_v/F_m),and ratios of F_m/F_o and F_v/F_o,but the effects decreased with the prolongation of drought stress.The SOD and POD activities of poplar leaves were higher in short time (1 h) drought stress than in longer time (3 h) one.The activity of POD was increased by SNP,while that of SOD was changed little.With increasing SNP level,the POD and SOD activities first increased and then decreased.The NO donor could retard the accumulation of active oxygen through inducing POD and SOD activities,alleviate the effects of drought stress on photosynthesis,and increase the drought-resistance of poplar.

Dynamics of litterfall and its decomposition and nutrient return of shoot-used Dendrocalamus latiflorus in Mountainous areas of Fujian Province

QIU Erfa, CHEN Zhuomei, ZHENG Yushan, HONG Wei, HUANG Baolong

2005, 16(5): 811-814.

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This paper studied the dynamics of nutrients in the litters of shoot-used Dendrocalamus latiflorus planted in Nanjing State-owned Forest Farm of Fujian Province.The results showed that the litterfall as well as its nutrient concentration and return varied obviously with seasons,and had a double-peak curve change.The weight loss during litter decomposition was very fast at first,and then slowed down.There was a negative exponent correlation between remained weight and decomposition time.During decomposition,the concentrations of N and P in litter showed a trend of increase-decrease-increase,while the K loss was intensive at the early stage,gently at mid-stage,and slight at late stage.

Spatial and temporal pattern of Castanopsis fargesii seed rain in evergreen broad-leaved forest in Tiantong National Forest Park of Zhejiang,China

HU Xingming, CAI Yongli, LI Kai, ZHANG Tianshu

2005, 16(5): 815-819.

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Five mature plants of Castanopsis fargesii population were randomly chosen to study the spatial and temporal pattern of its seed rain in Tiantong National Forest Park,Zhejiang Province in 2003.The duration of seed rain observed from the five samples was about 45 days,from November 3^rd to December 16^th,with a distinguishable dropping peak between November 18^th and 27^th.The average seed rain density estimated from the traps deployed under the crown was 112.8 seeds穖^-2,ranging from 70 to 239.5 seeds穖^-2.Of the total acorns collected by seed traps,the viable accounted for 27.3%,the immature 25.7%,the eaten by rodents 5.0%,and the infected by larvae 42.0%.The acorns on the ground mainly distributed under the parent tree crown within 8 m from the trunk,and the spatial pattern of seed density on the ground fitted the quadratic distribution.

Dynamic characters of sulphur and heavy metals concentrations in Pinus taiwanensis growth rings

WU Zemin, GAO Jian, HUANG Chenglin, HONG Shuyuan

2005, 16(5): 820-824.

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Based on the concentration analyses of S,Mn,Fe,Zn,Cu and Pb in the growth ring set of Pinus taiwanensis at the summit (1 400～1 600 m alt.) of Huangshan Mountains during past 80 years,this paper studied the dynamic characters of element concentrations in the ring set,and their relationships with atmospheric environment.The results showed that there were three levels of S concentration in the growth ring set,i.e.,low concentration (less than 2 mg·kg^-1),accounted for 58.5% of the ring set; medium (3.65～6.0 mg·kg^-1),accounted for 24.4%; and high (>11.0 mg·kg^-1),accounted for 17.1%.The dynamic change of S accumulation in the ring set displayed an obvious fluctuation,which could be divided into 3 major types,i.e.,fluctuation during 1917～1960,relatively stable during 1961～1980,and gradual increase after 1981.In the growth ring set of 1935～1938,1959～1960,and recent 10 years,the S accumulation concentrations were all higher than 11 mg·kg^-1,suggesting the relatively high atmospheric S concentration in those periods.There was a significant correlation between the increase of tourist amount in Huangshan scenic spot and the S concentration in growth ring set.The fuel fume centralized in some places might result in the atmospheric pollution at local scale,which in turn,might influence the S accumulation in growth ring set.The Pb accumulation concentration in the ring set was less than the background value in soil.The accumulation concentrations of Mn,Fe,Zn and Cu showed fluctuation characteristics,with independence of each other.The accumulation of Zn and Cu in growth rings had no correlation with tree age,while that of Mn and Fe was in adverse.The Mn concentration in the growth ring set decreased with tree age but increased in recent growth rings,while the Fe concentration was on the contrary,which needed further study.

Landscape ecological evaluation of Fenglin Nature Reverse:Quantification and interpretation

GUO Qingxi, WANG Tianming

2005, 16(5): 825-832.

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Fenglin National Class Nature Reserve is the largest well-saved virginal Korean pine(Pinus koraiensis) forest area and a precious species gene bank in China.In this study,the indexes diversity,naturalness,representativity,rarity,area suitability,stability,and anthropogenic interference were selected to establish a ranking ecological evaluation system to estimate the ecological condition of the Reserve.The value of each index was determined by the evaluation system,and the weight percentage was decided by Analytical Hierarchy Process(AHP).In the Reserve,there were 568 higher plant species belonging to 113 families and 220 higher animal species,with score 3 of species diversity.The zonal "climax" vegetation type broad-leaved Korean pine forest and the intrazonal community type spruce-fir forest constituted the principal part of the Reserve forest,which was the epitome of the virgin broad-leaved Korean pine forest in Lesser Xing'an Mountains,with representativity score 3.During the past 20～30 years,the natural habitat in the Reserve was quite good,and secondary succession was obtained effective control with few natural or anthropogenic disturbance,with score 4 of naturalness and anthropogenic interference.There were a lot of ancient species of the tertiary period,such as Pinus koraiensis,Fraxinus mandsurica,Juglans mandshurica,Pellodendron amurense,Tilia amurensis and Acer mono,and Pinus koraiensis was listed as one of severe danger species by the FAO of UN,with rarity score 4.The Reserve covered an area of 18165 hm²,with an enough size to maintain the structure and function of the ecosystem.Accordingly,its area suitability score was 4.Broad-leaved Korean pine forest was the most typical and stable vegetation type in the Reserve,and thus,its stability score was 4.Finally,the composite evaluation index (CEI) was figured out as 0.87,showing that the ecological quality of the Reserve was very good,and the protection value was quite high.In conclusion,the present area,structure,and management of the Reserve could satisfy the requirement of sustainable development.

GIS-based forest fire risk zone mapping in Daxing'an Mountains

YIN Haiwei, KONG Fanhua, LI Xiu-zhen

2005, 16(5): 833-837.

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In this study,the Yuying and Fendou forest farms of Tuqiang Forest Bureau in Daxing'an Mountains were chosen as test areas,and their vegetation type,altitude,slop,aspect,and settlement buffer were selected as the main forest fire factors.The circumstances of forest fire risk were quantified by the factor-weights union method with the support of GIS.Four classes of forest fire risk ranging from low to extreme were generated.The none-,low,moderate,high,and extremely high fire risk zones accounted for 0.37%,0.63%,38.67%,58.63% and 1.70%,respectively,which was in corresponding with normal distribution.About 60.33% of the test areas were predicted to be upper moderate risk zones,indicating that the forest fire management task in these areas is super onerous.There was an obvious regional difference in the distribution of forest fire risk zones,being higher in the center and lower around the center,and the difference in fire factors was also obvious.The GIS-based forest fire risk model of test areas strongly cohered with the actual fire-affected sites in 1987,which suggested that the forest fire risk zone mapping had a higher reliability,and could be used as the reference and guidance of forest fire management.

Forest fire spread modeling and 3D visualization in virtual forest landscape

LI Jianwei, CHEN Chongcheng, YU Qizhi, PAN Zhigeng

2005, 16(5): 838-842.

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The traditional method for simulating the behaviors of forest fire is to use a single ellipse to represent all of the fire points in fire scene,which has many disadvantages,e.g.,the simulated result is quite different to the real situation,and it is mainly based on 2D.As a result,the represented information is limited.In this paper,the most widely used Rothermel fire spreading model and the principal of Huygen were adopted to simulate the behaviors of forest fire in different position and wind direction,and the results were shown by pseudo-particle system in 3D,which could not only get the area of fire suffering,the direction of fire spreading and the size of fire,but also provide realistic simulation to observers.The method has been successfully applied to Zhangpu forest in Fujian Province.

Application of inverse Lagrangian dispersion analysis in simulating forest evapotranspiration

WANG Anzhi, DIAO Yiwei, JIN Changjie, GUAN Dexin, PEI Tiefan

2005, 16(5): 843-848.

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Based on the localized near field (LNF) theory and coupled with the distribution of vertical velocity standard deviation (σ_{w_(z)}) and Lagrangian integral time scales T_L(z) within the canopy proposed by Raupach,the relationship between water vapor source/sink distribution and its mean concentration profile was constructed.The estimation of forest evapotranspiration was also conducted by the inverse Lagrangian dispersion analysis,which can calculate the water vapor source/sink distribution from its mean concentration profile.The calculated forest evapotranspiration was compared with the measured values.It was concluded that the simulated precision of the daily daytime evapotranspiration could reach 87.3%,the calculated results was 15%～25% higher than the measured one,the nighttime evapotranspiration was about 70% of the daily value,and the total monthly evapotranspiration from June to August was higher than that in May and September.

Dynamic distribution characters of herbaceous vegetation root systems in abandoned grasslands of Loess Plateau

LI Peng, LI Zhanbin, TANTAI Zhan

2005, 16(5): 849-853.

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The investigation on the vertical distribution characters of herbaceous vegetation root systems in abandoned and natural grasslands of Loess Plateau by the method of soil auger showed that there were no significant differences in root system distribution patterns between different sampling points,and the related root indexes could be used to indicate the vertical distribution characters of vegetation roots.The main root indexes including root biomass and root length were decreased with increasing soil depth,but increased with increasing abandoned years.After abandoned for more than 20 years,the root distribution characters of abandoned grassland were approached to that of natural grassland.The root extinction coefficient decreased with increasing abandoned years,indicating that more and more roots were concentrated in surface soil layer with the increase of abandoned time,which was helpful to the improvement of soil physical and chemical properties,and beneficial to the new species intrusion and vegetation succession.

Dynamics of bud flow and bud bank of Phragmites communis population in dry land habitat of alkalinized meadow in the Songnen Plains of China

YANG Yunfei, WEI Chunyan, ZHANG Baotian, LIU Bao

2005, 16(5): 854-858.

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In the dry land habitat of alkalinized meadow in Songnen Plains,the rhizomes of Phragmites communis population are distributed in different depths of one meter soil layer,which usually live for 6 years and a few for 7～9 years or even longer.Based on the investigation of their buds,a "bud flow" model of the population was established,and the method for estimating the dynamics of its bud bank storage,i.e.,adding the input rate of 1 st year age-class rhizome buds to the storage rate of other age-classes dormant buds in the bank,was put forward.The results showed that the input rate of the bud bank increased with plant growth seasons while the burgeoned output rate exhibited a decreasing trend,whereas the output rate of the dead remained at a low level on the whole.By the end of September in the early dormant period,the input rate of the bud bank was as 2.04 times as its output rate,and the dormant buds of each age-class manifested a steady burgeoned output.Quantitative analysis indicated that the burgeoned output rate of dormant buds increased by 11% each year.In another word,11% of different age-classes dormant buds would germinate and form one-year class new rhizomes.The top of one-year class new rhizomes would develop to ramets in the next year,which would transport nutrients to nearby old-age rhizomes,and thus,maintain the vitality of old-age class rhizomes.

Effects of environmental factors on AM fungi around steppe plant roots in Tibet Plateau

CAI Xiaobu, QIAN Cheng, PENG Yuelin, FENG Gu, GAI Jingping

2005, 16(5): 859-864.

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The study on the representative steppe plant species in Tibet Plateau showed that the density of AM fungi spores in host plant rhizosphere did not correlate with the infection rate of AM fungi.The big changes in air temperature and rainfall at different altitudes played an important role in determining the growth and infection of AM fungi specific to steppe plants,and steppe type and soil texture also had obvious effects on AM fungi's growth and infection.Within a certain range,the spore density increased significantly with increasing soil pH (r=0.5319 *,n=20),but showed a declining trend with the improvement of soil organic matter (r=-0.1973,n=20).In contrast,the infection rates of AM fungi to host plants were to some extent negatively and positively correlated with soil pH and soil organic matter,respectively.Phosphorus (P) enrichment in soil environment led to the inhibition of the reproduction and infection of AM fungi.The suitable soil pH,OM and Olsen P contents for the growth and reproduction of AM fungi ranged from 8.0～8.7,3.8～4.8 g·kg^-1 and 7.8～10.1 mg·kg^-1,respectively.Moderate and serious degradation of steppe (especially the serious degradation) had negative or detrimental impacts on the reproduction and infection of AM fungi.Reasonable grazing was helpful to the conservation of critical species of AM fungi.AM fungi also showed a relatively high infection rate on the roots of sedge species such as Carex praecpara,Kobresia humilis and Cyperus compressus.

Effects of AM fungi on drought tolerance of citrus grafting seedling trifoliate orange/cara cara

WU Qiangsheng, XIA Renxue

2005, 16(5): 865-869.

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With pot experiment in a greenhouse,this paper studied the effects of arbuscular mycorrhizal (AM) fungi Glomus mosseae on the drought tolerance of citrus grafting seedling trifoliate orange/cara cara under natural water stress and rewatering.The results showed that inoculation with AM fungi significantly increased the plant height,stem diameter,leaf area,and shoot length of test seedling.At the 4^th day of rewatering,mycorrhizal plant had significantly higher root soluble protein content and superoxide dismutase (SOD) and catalase (CAT) activities than non-mycorrhizal plant.An interaction between water and AM fungi could significantly promote leaf SOD activity.During natural water stress and rewatering,AM fungi inoculation could decrease the leaf content of malondialdehyde (MDA),increase those of soluble sugar and soluble protein,and enhance the activities of SOD,peroxidase (POD) and CAT.As a result,the capability of osmotic adjustment and protective recovery,and thus,the drought tolerance of mycorrhizal citrus grafting seedling were improved.The mechanism that AM fungi could enhance the drought tolerance of host plant might be related to the protective system of host plant.

Dendrolimus sppdamage monitoring by using NOAA/AVHRR data

ZHANG Yushu, BAN Xianxiu, CHEN Pengshi, FENG Rui, JI Ruipeng, XIAO Yan

2005, 16(5): 870-874.

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This paper approached the feasibility of quantitatively monitoring Dendrolimus spp.damage by using NOAA/AVHRR data.The damaged rate of needle leaf was used to represent Dendrolimus spp.harming degree,and <30%,30%～60% and >60% of damaged rate was defined as low,medium and severe harming degree,respectively.The correlation equation of damaged rate and normalized vegetation index (NDVI) was established,based on the ground spectrum observation.The NDVI was 0.8823 when no damage occurred.A relative NDVI value of damaged to undamaged area was used to express the remote sensing index of low,medium and severe harming degree.The index was 1 for undamaged forest,and 0.78～1,0.57～0.78 and <0.57 for low,medium and severe harming degrees,respectively.The mixed pixels were separated by linear addable vertical vegetation index in the monitoring,and the quantitative monitoring and analysis was accomplished for years when the three damage degrees happened.It was shown that AVHRR data could be more available in quantitatively monitoring and analyzing serious damage,while low degree damage was difficult to distinguish by AVHRR data,due to the differences of surface properties and atmospheric influences,as well as the lower space resolution of NOAA/AVHRR.The damaged area estimated by AVHRR was 12.1%～14.3% lower than that by TM.

Dynamics of fluvo-aquic soil organic matter fractions under long-term fertilization

YIN Yunfeng, CAI Zucong, QIN Shengwu

2005, 16(5): 875-878.

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By the method of relative density fractionation,this paper studied the dynamics of organic matter and its light and heavy fractions in a fluvo-aquic soil under long-term fertilization.The results indicated under current fertilization system,the contents of soil organic matter and its light and heavy fractions were basically unchanged within 13 successive years of no fertilization,but had an increasing trend with the duration of chemical fertilizer NPK and organic manure applications,with a larger fluctuation among years and a less increment in treatment NPK.Regression analysis showed that soil organic matter and its light and heavy fractions had a linear correlation with the duration of fertilization in treatment NPK,and had a logarithm correlation in treatment organic manure.

Individual grain yield potential and nitrogen utilization efficiency of Zea mays cultivars widely planted in North China

WANG Kongjun, ZHANG Jiwang, GUO Yuqiu, HU Changhao, DONG Shuting, JIANG Gaoming

2005, 16(5): 879-884.

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With field experiment and under low-density condition,this paper studied the individual grain yield (GY) and nitrogen utilization efficiency (NUE) of fifty Zea mays cultivars widely planted in North China since 1990s.Exploring analyses and normality tests showed that the 1000-kernal weight (KW),above-ground biomass per plant (AB),grain harvest index (HI_G),NUE,and nitrogen harvest index (HI_N) were all conformed to normal distribution,with N(265.1,44.50 2),N(322.3,36.91 2),N(515.8,64.73 2),N(0.514,0.06 2),N(43.0,5.37 2),and N(0.643,0.06 2),respectively.The GY ranged from 198.35 to 345.22 g穚lant^-1,KW from 241.50 to 391.82 g?1000 kernal^-1,AB from 402.34 to 712.84 g穚lant^-1,HI_G from 0.39 to 0.63,NUE from 31.18 to 57.35 g grain穏 N^-1,and HI_N from 0.47 to 0.74.Correlation analyses indicated that GY positively and significantly correlated with NUE (partial correlation coefficient was 0.471^**,P=0.001),while KW negatively and significantly correlated with NUE (Pearson correlation coefficient was -0.427^**,P=0.002).Through hierarchical cluster analyses for GY and NUE,the test Zea mays varieties could be sorted into 3 types,i.e.,high-GY with high-NEU,low-GY with low-NEU,and mediate type.Currently,only 24 percent of Zea mays cultivars in North China were of high-GY with high-NEU type,and thus,its breeding should be strengthened in the future.

Allelopathy and resources competition of rice under different nitrogen supplies

XIONG Jun, LIN Wenxiong, ZHOU Junjian, WU Minhong, CHEN Xiangxu, HE Huaqin, GUO Yuchun, LIANG Yiyuan

2005, 16(5): 885-889.

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In order to explore the bio-interference of allelopathic rice with barnyardgrass under different nitrogen supplies,a new bioassay method,i.e.,allelopathy-competition separation based (ACS) approach was recommended in this study.The results indicated that ACS could be successfully used to distinguish the rice allelopathy from its resources competition in rice-weed co-culture system,and to evaluate its response characteristics under different N supplies.The test rice accession PI312777 had a higher ability in interfering target weed barnyardgrass (BYD),represented by its stable and higher ability in resources competition,as well as its increasing allelopathic potential in suppressing companion weed BYD when the N supply decreased in the co-cultured system.The reverse was true in the case of rice accession Lemont,which had a lower allelopathic potential under all N supply levels,and a lower ability in resources competition under normal or rich N supply.But,Lemont had an obviously increased ability in resources competition under lower N supply,which was considered as the result of econiche competition in rice-weed system.

Interactive effects between allelochemical substitutes

HE Huaqin, SHEN Lihua, SONG Biqing, GUO Yuchun, LIANG Yiyuan, LIANG Kangjing, LIN Wenxiong

2005, 16(5): 890-894.

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In order to understand the allelopathic mechanisms of rice on weed,the allelochemical substitutes salicylic acid,p-hydroxybenzonic acid,cinnamic acid,vanillic acid and ferulic acid were used in an orthogonally gyrating regression experiment to study their interactive effects on the growth of barnyardgrass.The results indicated that whether the interactive effects between two substitutes,e.g.,between salicylic and cinnamic acid or between salicylic and p-hydrobanzonic acid,were synergistic or antagonistic depended on the concentrations of each substitutes in the mixture.In the mixture of salicylic acid and p-hydrobanzonic acid,the effect of salicylic acid was synergistic at <0.14 mmol稬^-1 but antagonistic at >0.14 mmol稬^-1,while p-hydrobanzonic acid showed an antagonistic effect at >0.425 mmol稬^-1.Salicylic acid at all test concentrations exhibited antagonism to cinnamic acid,while cinnamic acid had a synergistic at <0.14 mmol稬^-1,but an antagonistic effect at >0.14 mmol稬^-1 on alicylic acid.The interactive effects between cinnamic and ferulic acid were all synergistic at test concentrations.

Effects of pesticides metolachlor and S-metolachlor on soil microorganisms in aquisols of Southern China Ⅰ Catalase activity

ZHOU Ying, LIU Weiping, WANG Tingting

2005, 16(5): 895-898.

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This paper studied the effects of different concentrations (0,5,20,and 100 mg穔g^-1) metolachlor and its enantiomer S-metolachlor (Dual Gold) on soil catalase activity.The results showed that 20 mg穔g^-1 metolachlor had the most successive stimulating effect,5 mg穔g^-1 metolachlor had an inhibitory effect in the early period,while 100 mg穔g^-1 metolachlor had a stimulating effect in the late period.Different concentrations Dual Gold displayed a tendency stimulation-inhibition-stimulation.5 and 100 mg穔g^-1 metolachlor might have more damage on soil ecosystem than different concentrations Dual Gold.

Forms and bio-availabilities of exogenous arsenic in purple soils

MIAO Jinyan, HE Feng, WEI Shiqiang, LIU Gang

2005, 16(5): 899-902.

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This study showed that after As was added into purple soils for 10 days,50.2%～61.1% of it transformed into residual As,occupying 68%～86% in original soils.For acid purple soil,the As forms were Al-As >Fe-As>Ca-As;for neutral purple soil,they were Ca-As>Al-As>Ca-As>Fe-As>A-As,and for calcic purple soil,they were Ca-As>Al-As>Fe-As>A-As.It is suggested that NH₄Cl could be used as common extractant for different soils,because it slightly affected original As forms in soils,and showed a highly significant correlation (P=0.01) to plant absorption.From pluralistic regressive analysis of plant As content and each As form,Al-As and Fe-As were the main available forms in acid purple soil,but A-As and Ca-As were the most important fractions in neutral and calcic purple soils.The study also showed that H₃BO₃ could restrain the F interference in the operation of As speciation separations.

Maize growth and phosphorous-and zinc uptake under different phosphorous supply levels

ZHANG Fucang, KANG Shaozhong, GONG Daozhi, LI Zhijun

2005, 16(5): 903-906.

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By the method of solution culture,this paper studied the P and Zn uptake of maize at its growth stages under different P supply levels.The results showed that maize growth reached its maximum at the supply level of 100 μmol P·L^-1,while the root/shoot ratio was the highest at 0.1 μmol·L^-1 P supply.Increase of P concentration in culture solution promoted the uptake of P,but decreased its utilization rate.The Zn content in root increased with increasing P supply,while that in shoot varied little,which meant that the Zn transportation rate from root to shoot had little change with increasing P concentration.There was a positive correlation between the concentrations of Zn and P in maize seedling roots.

Analysis and identification of Liriomyza sativae-attractants from cowpea and kidney bean volatiles

WEI Ming, DENG Xiaojun, DU Jiawei

2005, 16(5): 907-910.

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In this paper,the volatiles from cowpea and kidney bean,the main host plants of American leafminer Liriomyza sativae,were collected and extracted by a self-designed device and solid phase microextraction (SPME) technique,and analyzed by GC-MS.The results showed that the volatiles from the two beans had the same components mainly consisted of 2-hexenal,3-Hexen-1-ol,2-Hexen-1-ol,1-Octen-3-ol,3-Hexenol acetate,α-Ionone and β-Ionone.The lure made of the seven components was attractive to L.sativae in field trapping trials.Detailed analyses indicated that α-Ionone and β-Ionone might play important roles in the searching behavior of L.sativae for host plants.

Population fluctuation of main pathogens and their antagonistic bacteria in cucumber rhizosphere

LIANG Jiangen, ZHANG Bingxin, YU Jingquan, SHI Jiang, CHEN Zhenyu

2005, 16(5): 911-914.

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The investigation on the population fluctuation of main pathogens Pythium spp.and Fusarium oxysporum f.sp.cucumerinum in the rhizosphere of four cucumber varieties showed that there was a significant difference in the population number of pathogens for different cucumber varieties and for different growth stages of the same variety,which was in accordance with the regular disease incidence pattern.The population number of Pythium spp.was significantly higher at cucumber creeping stage than at its other growth stages,while that of Fusarium oxysporum f.sp.cucumerinum was the highest at cucumber principal-fruiting stage.There was a closer positive relationship between two test pathogens and their antagonistic bacteria,with the correlation coefficient being 0.95 and 0.81,respectively.

Effects of cinnamic acid on physiological characteristics of Cucumis sativus seedling

WU Fengzhi, PAN Kai, ZHOU Xiuyan

2005, 16(5): 915-918.

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With substrate culture,this paper studied the effects of different concentrations of cinnamic acid on the physiological characteristics of Cucumis sativus seedling.The results showed that 25 μmol·L^-1 of cinnamic acid had an inhibition effect on carotenoids,but a promotion effect on chlorophyll a and b.50 μmol·L^-1 of this compound could significantly inhibit the photosynthetic rate,transpiration rate and root activity (P<0.05),and this effect was getting stronger when the concentration was higher.150 μmol cinnamic acid·L^-1 had a significant inhibition effect on chlorophyll a and b (P<0.05).Cinnamic acid had a weak inhibition effect on root activity when its concentration was low(25～50 μmol ·L^-1),but the effect was significant when the concentration was high (100～150 μmol·L^-1),which became stronger with the longer handling time (P<0.05).

Effects of Colletotrichum higginsianum infection on endogenous hormones in Brassica parachinensis leaves under different nitrogen nutrition

YANG Xian, CHEN Xiaoyan

2005, 16(5): 919-923.

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This paper studied the effects of Colletotrichum higginsianum infection on the ethylene production and the contents of abscisic acid (ABA) and indole-3-acetic acid (IAA) in leaves of flowering Chinese cabbage (Brassica parachinensis) under six levels of nitrogen (N) nutrition,and their relations to disease-resistance.The results showed that the ethylene production in all N treatments had a mono-peak curve change,and reached the maximum 4～6 days after inoculation.In comparing with high N or non-N treatment,medium or low N treatment could inhibit ethylene production and ABA synthesis,and keep ethylene and ABA stable in Colletotrichum higginsianum-inoculated plants.The IAA content in medium or low N treatment increased gradually,while that in high N or non-N treatment had a mono-peak curve change,and reached the maximum 4～6 days after inoculation.The IAA content in medium or low N treatment increased more with inoculation time,indicating that there was a close relationship among N nutrition,endogenous hormones and anthracnose.It is important for plants' disease-resistance to keep the balance of endogenous hormones.

Effects of free-air CO₂ enrichment (FACE) on phosphorus nutrition of Oryza sativa at its different growth stages

YANG Lianxin, YANG Hongjian, HUANG Jianye, WANG Yulong, ZHU Jianguo, LIU Hongjiang, DONG Guichun, SHAN Yuhua

2005, 16(5): 924-928.

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Using free-air CO₂ enrichment (FACE) platform and under different nitrogen supply level,this paper studied the phosphorus nutrition of Oryza sativa at its different growth stages.The CO₂ concentration of FACE platform was 200 μmol·mol -1 more than that in ambient air,and the nitrogen supply levels were 150 kg·hm^-2,250 kg·hm^-2 and 280 kg·hm^-2.The results showed that during rice growth period,FACE significantly increased the phosphorus content of rice plant and its phosphorus uptake by 3.9%～20.6% and 28.9%～71.4%,respectively.Before heading,FACE had little effect on the phosphorous accumulation in leaf or stake,but after heading,it made the proportion of phosphorus accumulation in reproductive organ decreased by 9.8%～26.3% and that in vegetative organ increased by 2.2%～23.9% at 0.01 or 0.05 significant level.Under FACE treatment,the phosphorus use efficiency for biomass production (PUEp) at different growth stages,the phosphorus use efficiency for grain output (PUEg),and the phosphorus harvest index (PHI) were decreased by 3.7%～16.6%,6.5%～15.5%,5.4%～9.0%,respectively.Nitrogen supply level and its interaction with FACE had less effect on the phosphorus nutrition of rice at its different growth stages.

Concentrations of metallic elements,N and S in Sabina chinensis cvpyramidalis leaves along urban-rural roadways of Nanjing city

YIN Yunlong, LUO Yongming, ZHANG Taolin, HE Jianfeng, XU Jianhua

2005, 16(5): 929-932.

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This paper measured the concentrations of metallic elements,N and S in soils and Sabina chinensis cv.pyramidalis leaves along the urban-rural roadways (urban trunk roads,belt highway,and suburban roads) of Nanjing city,with botanical garden as un-traffic impacted reference site,and discussed the transfer of test elements among atmosphere,plant and soil,as well as the impact of traffic- related pollution.The results showed that the concentrations of Al,Fe,Mo,Zn,Cd,Pb,As and Cr in Sabina chinensis leaves were significantly higher along urban-rural roadways than at reference site,being most remarkable for Al,Fe,Mo and Zn.The positive correlations between soil and Sabina chinensis leaf Fe,Zn and As concentrations in road environment indicated that Sabina chinensis might be a good indicator plant of soil Fe,Zn and As.The correlations between soil and plant leaf Al,Mo,Cu,Pb,Cd and Cr concentrations were not remarkable,and thus,their high concentrations in Sabina chinensis leaf in road environment might be caused by air pollution.The concentrations of N and S in Sabina chinensis leaf were higher along urban trunk roads and belt highway than at reference site,while those along suburban roads were similar to the reference.There was a negative correlation between soil and plant leaf N,and a positive correlation between soil and plant leaf S.The N content in roadside soil was lower,while the S content was higher than the reference,indicating that the higher Sabina chinensis leaf N content in road environment might be caused by the NO_x from exhaust gas emission,and the higher leaf S content should be come from soil.

Responses of antioxidation system of Cynodon dactylon to recirculated landfill leachate irrigation

WANG Ruyi, HE Pinjing, SHAO Liming, ZHANG Bin, LI Guojian

2005, 16(5): 933-938.

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With pot experiment,this paper studied the membrane lipid peroxidation and the variations of antioxidation system in Cynodon dactylon under recirculated landfill leachate irrigation.The results showed that when irrigated with low dilution ratio (<25%) leachate,the chlorophyll a/b ratio increased with increasing dilution ratio,cell membrane permeability and MDA and H₂O₂ contents were in adverse,and membrane lipid peroxidation was relatively weak.However,with the increasing leachate dilution ratio (>25%),there existed an obvious negative effect on Cynodon dactylon,i.e.,the chlorophyll a/b ratio decreased,while cell membrane permeability and MDA and H₂O₂ contents increased,which meant that the membrane lipid peroxidation was accelerated.The contents of antioxidants AsA,GSH and Car also showed the similar trend,i.e.,they increased with increasing leachate dilution ratio when irrigated with low dilution ratio leachate,but decreased under medium or high dilution ratio leachate irrigation.Among three test anti-oxidative enzymes,SOD and POD activities showed a similar change to test antioxidants,and POD activity was more sensitive,while CAT activity was on the contrary.The contents of test antioxidants and the activities of SOD and POD were negatively and significantly correlated to MDA content,indicating that they might play an important role in preventing Cynodon dactylon from cell membrane lipid peroxdation.

Spatial variation of microbial properties in a creosote-contaminated soil

YANG Xiuhong, LI Shiyu, Gran Bengtsson, Niklas Trneman

2005, 16(5): 939-944.

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By the methods of geostatistics,this paper studied the spatial variation of microbial biomass,microbial community structure and microbial activity in a creosote-contaminated soil.The microbial biomass was indicated by the total amount of 26 examined phospholipid fatty acids (totPLFA),the microbial community structure was characterized by the first two principal components (PC1 and PC2) of the PLFA patterns through subjecting the PLFAs to principal component analysis,and the total amount of CO₂-C respired (C_re) during incubation was used to describe the soil microbial activity.The results showed that most of the variables exhibited various degrees of spatial autocorrelation,and spherical models with nugget could fit their semivariograms.The estimated spatial dependence distances of the variables varied from 2.50 to 16.60 m.The PLFA PC1,totPLFA and C re displayed relatively high spatial dependences,their relative structural variance,i.e.,the proportion of total variance that can be attributed to the spatial autocorrelation,being 82.3%,79.6% and 64.7%,respectively,while PLFA PC2 was not spatially autocorrelated.The kriged maps showed that there were several hot spots with relatively high microbial biomass and high microbial activity located in the study site.Gram- negative bacteria characterized by PLFAs 16:1^ω7t,cy17:0,18:1^ω7 and cy19:0 were the dominant community in these hot spots.The concentration and spatial distribution of polycyclic aromatic hydrocarbons as the main contaminants in the soil could be one of the important factors affecting the spatial variation of soil microbial properties.

Phytoremediation of mercury and cadmium polluted wetland by Arundo donax

HAN Zhiping, HU Xiaobin, HU Zhenghai

2005, 16(5): 945-950.

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With a pot culture of simulated mercury (Hg) and cadmium (Cd)-polluted wetland,this paper studied the capability of Arundo donax in accumulating these heavy metals,and their distribution in the plant.The results showed that after grown in a 101 mg·kg^-1 Hg-polluted wetland for 8 months,the Hg-concentrating capability of Arundo donax was in order of root>stem>leaf,and the Hg concentration in its aboveground parts was 200±20 mg·kg^-1(DW); while in the case of 115 mg·kg^-1 Cd-pollution,the Cd-concentrating capability was in order of leaf>root>stem,and the Cd concentration in leaf was 160±26 mg·kg^-1(DW).The heavy metals concentration in Arundo donax organs increased with its growth time,being 30%～50% higher for 8 months than for 4 months.The BCF (Bio-concentration factor) decreased with increasing heavy metals concentration.In polluted wetland,the BCFs of Hg by the leaf and stem were 1.9 and 2.1,and those of Cd were 1.5 and 0.3,respectively; while in unpolluted wetland,the concentration of Hg and Cd was 6.8 and 8.5mg·kg^-1,the BCFs of Hg by the leaf and stem were 6.8 and 12.2,and those of Cd were 7.0 and 2.7,respectively.It was indicated that Arundo donax not only had the characters of large biomass,exuberant root,and good adaptability,but also exhibited high tolerance and concentrating capability to Cd and Hg.

Effects of simulated nitrogen deposition on weeds growth and nitrogen uptake

JIANG Qiqing, TANG Jianjun, CHEN Xin, CHEN Jing, YANG Ruyi, Hu S

2005, 16(5): 951-955.

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In this paper,a greenhouse experiment was conducted to study the responses of different functional groups of weeds to simulated nitrogen deposition (4.0 g N穖^-2穣r^-1).Native weed species Poa annua,Lolium perenne,Avena fatua,Medicago lupulina,Trifolium repens,Plantago virginica,Veronica didyma,Echinochloa crusgalli var.mitis,Eleusine indica and Amaranthus spinosus in orchard ecosystem were used as test materials,and their above-and underground biomass and nitrogen uptake were measured.The results showed that under simulated N deposition,the total biomass,shoot biomass and root biomass of all weed species tended to increase,while the total biomass was differed for different functional groups of weeds.The biomass of C₄ grass,C₃ legumes and C₃ grass was significantly increased under N deposition,while that of C₃ and C₄ forbs was not significantly impacted.The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition,but that of Poa annu,Lolium perenne,Medicago lupulina,Trifolium repens and Amarathus spinosus was not impacted significantly.N deposition had no significant effect on plant N concentration,but significantly enhanced the N uptake of all test weed species except Amarathus spinosus,Poa annua and Veronica didyma.It was suggested that the further increase of N deposition might speed up the changes of the community structure of weed species due to their different responses to N deposition.

Extraction method of soil microbial DNA for molecular ecology study

ZHANG Yuguang, LI Diqiang, WANG Huimin, XIAO Qiming

2005, 16(5): 956-960.

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In environmental microbiology,molecular ecology study has been widely concerned in the world,while high quality DNA is the basis of the study.In our study,soil microbial DNA was extracted by the methods of SDS lysis and denaturant plus SDS lysis,and purified with gel electrophoresis plus minicolumn and double minicolumn methods.The results showed that denaturant plus SDS lysis could extract DNA more efficiently,and gel electrophoresis plus minicolumn could help to obtain purer DNA that was available in amplifying its 16S rDNA and functional genes by PCR.Therefore,denaturant plus SDS lysis could be an efficient and reliable method to extract DNA in molecular ecology studies.

Carrying capacity of shellfish culture in Dadeng Island sea area of Xiamen

LU Zhenbin, DU Qi, FANG Minjie, QIAN Xiaoming, CAI Qinghai, XU Cuiya

2005, 16(5): 961-966.

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To fully and rationally exploit local living marine resources while have a sustainable,efficient and healthy development of shellfish culture in the Dadeng Island sea area of Xiamen,this paper determined and analyzed the related model parameters of this area,including chlorophyll a,primary productivity,phytoplankton organic carbon content,wild filter feeder yields in subtidal and intertidal zones and suspension culture area,cultured shellfish filtration rate and organic carbon content,shellfish's total weight to fresh meat ratio,and adopted the Nutrient Dynamic Model and Coastal Waters' Energy Flow Analysis Model to estimate the ecological capacity of shellfish in this area,from which,the wild filter feeder yields were deducted for estimating shellfish carrying capacity.The model established by Fang Jianguang was also used to estimate the shellfish carrying capacity.Statistics analysis was used to estimate the suitable culture area of shellfish and other species,aiming at limiting local shellfish culture and optimizing the culture of various species mollusks.According to the estimation of the three models,the shellfish carrying capacity in this area should be 35 248～39 990 tons,with an average of 37 488 tons,and 140 008×10⁴～158 850×10⁴ individuals,averaging 148 903×10⁴.The theoretically suitable culture area was 2 145 hm²,1 900 hm² for Ostreidae,81 hm² for razor clam (Sinonovacula constricta),20 hm² for blood clam (Tegillarca granosa),and 144 hm² for musculus (Musculus senhousei).In 2000,the actual culture area of shellfish and other species in the waters around Dadeng surpassed the estimated suitable culture area.It is proposed that some measures should be taken to reduce the overexploited area.

Effects of culture condition on fatty acids in Pseudomonas sp

YE Fangting, YAN Xiaojun, ZHENG Li, XU Jilin, CHEN Haimin

2005, 16(5): 967-970.

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The investigation on the growth of Pseudomonas sp.and the dynamics of its fatty acids under various culture conditions indicated that the optimum temperature for its growth was 30 ℃,and the best carbon source was starch.13 kinds of fatty acids were detected,among which,c16:1(n-7),c15:0,c16:0,c17:0,c18:1(n-6),c18:1(n-9),9,10-cp-c17:0 and iso9,10-cp-c17:0 were the major ones.When cultured at 30 ℃,the relative content of unsaturated fatty acids decreased significantly.Carbon source in the media was the crucial factor affecting the contents of odd- and cyclopropane fatty acids.Cluster analysis revealed that temperature had a more obvious effect than carbon source.

Roles of calcium in stress-tolerance of plants and its ecological significance

JIANG Tinghui, ZHAN Xinhua, XU Yangchun, ZHOU Lixiang, ZONG Lianggang

2005, 16(5): 971-976.

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Calcium loss from soil has dramatically increased for decades due to the increase of nitrogen input and/or the extension of acid rain,while calcium input into soil has declined substantially for the replacement of superphosphate by ammonium phosphate in fertilization,which intensified the imbalance of calcium input and output in agro-ecosystems,and needed to be solved in the near future for the sustainability of agriculture in such a country like China where the arable land resource is very limited.In recent years,the intensified soil acidification is mainly attributed to the root proton secretion stimulated by fertilization,and the nitrogen input from precipitation near industrialized regions promotes plant growth but results in other nutrients deficiency,which in turn acidifies soil and causes tree death.One of the most important mechanisms of saline soil bioremediation by sesbania is the activation of soil calcium by sesbania's proton secretion and the increase of soil calcium supply for subsequent crops.The present paper summarized the roles of calcium in plant tolerance to the stresses like acidosis,toxic metals,osmosis,ammonium toxicity,drought,extreme temperature (cold or heat shock),anoxia and pathogen infection,and the measures for maintaining soil calcium fertility.It was suggested that the production of ammonium phosphate should not be a pursued target for China's phosphorus fertilizer industry,and the roles of calcium in plant growth should be taken into account in fertilization experimental designs to make the experiments more accurate.

A landscape ecological approach for urban non-point source pollution control

GUO Qinghai, MA Keming, ZHAO Jingzhu, YANG Liu, YIN Chengqing

2005, 16(5): 977-981.

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Urban non-point source pollution is a new problem appeared with the speeding development of urbanization.The particularity of urban land use and the increase of impervious surface area make urban non-point source pollution differ from agricultural non-point source pollution,and more difficult to control.Best Management Practices (BMPs) are the effective practices commonly applied in controlling urban non-point source pollution,mainly adopting local repairing practices to control the pollutants in surface runoff.Because of the close relationship between urban land use patterns and non-point source pollution,it would be rational to combine the landscape ecological planning with local BMPs to control the urban non-point source pollution,which needs,firstly,analyzing and evaluating the influence of landscape structure on water-bodies,pollution sources and pollutant removal processes to define the relationships between landscape spatial pattern and non-point source pollution and to decide the key polluted fields,and secondly,adjusting inherent landscape structures or/and joining new landscape factors to form new landscape pattern,and combining landscape planning and management through applying BMPs into planning to improve urban landscape heterogeneity and to control urban non-point source pollution.

Effects of Pb²⁺ and Cd²⁺ pollution on physiological characteristics of Thuidium cymbifolium

WEI Haiying, Fang Yanming, YIN Zengfang

2005, 16(5): 982-984.

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This paper dealt with the effects of ²⁺,²⁺ and their combined pollution on the contents of chlorophyll,potassium and calcium in Thuidium cymbifolium.The results showed that except at 0.1 mg ²⁺稬^-1,the chlorophyll content decreased with increasing ²⁺ and ²⁺ concentrations,which was 18% of the control at 100 mg ²⁺稬^-1,and decreased by 48.6% at 200 mg ²⁺稬^-1.The potassium and calcium contents also decreased with increasing pollutants concentrations,being decreased by 61.1% at 100 mg ²⁺稬^-1.²⁺ had a stronger toxicity than ²⁺,and the toxicity of their combined pollution was stronger than that of each pollutant.²⁺ could increase the toxicity of ²⁺.

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