Table of Content

18 April 2006, Volume 17 Issue 04

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Articles

Species diversity and community structure of forest communities in Lishan Mountain

RU Wenming^1,2;ZHANG Jintun^1,3;ZHANG Feng¹;ZHANG Guiping1,2;LIU Ruixiang^1,2

2006, 17(04):  561-566 . 

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Lishan Mountain is belonged to the Zhongtiao Ranges in Southeast Shanxi,and situated between 35°16′30″～35°27′20″N and 111°51′～112°5′35″E.The climate is cool and arid in winter,but warm and rainy in summer.This paper studied the species diversity and community structure of forest communities there,based on field investigation data and by using diversity,richness and evenness indices.The results showed that the species diversity and evenness of the communities were in the order of Acer davidii + Acer mono>Acer davidii+Carpinus turczaninouii>Quercus liaolugensis>Quercus varibilis> Pinus armandii + Betula albo-sinensis>Pinus tabulaeformis + Quercus glandulifera>Betula platyphylla>Platycladus orientalis + Quercus variabilis>Betula albosinensis>Pinus armandii>Platycladus orientalis>Pinus tabulaeformis>Populus davidiana + Betula albo-sinensis.The diversity and richness of shrub layer were higher than those of herb layer and arbor layer,but the evenness of arbor,shrub and herb layers had no significant difference.There were positive correlations (P<0.05) between Shannon-Wiener index,Hill index,and species richness from 1 000 m to 1 920 m above sea level,but negative correlations (P<0.05) from 1 920 m to the top of the Mountain.The species diversity showed a “mid-altitude bulge” pattern with the change of altitude,and the reason was that the combination of temperature and moisture conditions from 1 000 m to 1 920 m above sea level was improved,and human disturbance was decreased gradually.

Additive partitioning of tree species diversity in Tiantong National Forest Park

CHEN Xiaoyong^1,2;LU Huiping¹;YING Xiangyang¹;SONG Yongchang^1,2

2006, 17(04):  567-571 . 

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In recent decade,the additive partitioning of species diversity has been revived,and used to describe a variety of diversity patterns.This paper analyzed the additive partitioning of tree species diversity in Tiantong National Forest Park,based on species richness,Shannon index and Simpson index.For species richness,small part was partitioned within plots,and most diversity was partitioned among plots or (sub-) associations.For example,in Schimeto-Castanopsietum fargesii association,only 20.3% of the species richness was assigned within plots.However,for Shannon index and Simpson index,most diversity was partitioned within plots,because these indices gave consideration to both species number and its abundance in each plot.The results of additive partitioning were also compared to those of traditional method in this paper.

Distribution pattern of natural vegetation along moisture gradient at north edge of Ordos Plateau:A preliminary study

YANG Xiaohui;LI Chaosheng;YU Chuntang;CI Longjun

2006, 17(04):  572-576 . 

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With Duguitala Township in the north part of Hangjin County as an example,this paper studied the spatial distribution pattern of natural vegetation along moisture gradient at the north edge of Ordos Plateau.The results showed that based on TWINSPAN classification,the communities were dominated by mesophytes and xerophytes,and there were some halophytes in some quadrats.The similarity indices of neighboring quadrats could reflect the mosaic pattern of different type communities,and thus,the diversity and complexity of communities along this gradient,which could be reconfirmed by DCA ordination.The CCA ordination for quadrats and geomorphological factors indicated that in this transitional region,the formation of vegetation’s spatial distribution pattern was determined by moisture gradient,while the latter was controlled not by the distance from the main course of the Yellow River but by the change of micro-geomorphology.In the land exploitation of this region,relatively stable geo-morphological units should be taken into consideration,and large scale land exploitation through surface leveling should be avoided if shelterbelt measures and drainage and desalinizeation system were defective.This study would be helpful to the protection of natural vegetation and the integrated development of agriculture and animal husbandry.

Classification method of deciduous-conifer mixed forest in Jilin Province based on GIS-TM remote sensing image

WANG Lihai;ZHAO Zhengyong;YANG Qi

2006, 17(04):  577-582 . 

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To improve the accuracy of automatic classification and identification of TM remote sensing images in forest area,an expert system for automatically classifying and identifying deciduousconifer mixed forest was built up,based on the GIS technique,quantitative analysis on the internal relations between geographic factors such as DEM and slope aspect and environment factors like soil type,and qualitative analysis on the spectrum information and preclassification information of sensing images,aimed to build a classification knowledge system.Taking the TM remote sensing image of Wangqing Forest Bureau in Jilin Province as an example,the study showed that this expert system could obviously reduce the influence of mixed pixel and terrain shadow.The classification precision of this system was increased by 14.22%,compared with that of Iterative Self-Organizing Data Analysis Techniques Algorithm (ISODATA) unsupervised classification,and the Kappa index was 0.7556,which could help to classify needle,deciduous and mixed forests.Introducing GIS data into the expert system could also solve the problem that TM remote sensing image could not do,due to the loss of correct spectrum value in cloudy and shady area.

Soil properties under shrubs in arid area of oasis-desert transition belt

XU Wenqiang^1,2;LUO Geping¹;CHEN Xi¹

2006, 17(04):  583-586 . 

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In arid and semi-arid areas with sparse vegetation cover,the spatial pattern of surface soil had a definite effect on soil salinity and nutrient flow,which is of highly importance for understanding the processes of land cover change.In this paper,a total of 3 shrub types and 2 soil sampling depths (0～20 and 20～40 cm) in the arid area of oasisdesert transition belt were selected to assess the spatial heterogeneity of soil resources under shrubs.The results showed that different types of shrub had no significant effect on the particle size distribution of soil which was mainly composed of sand and silt,but significant cluster effect was observed under Tamarix ramosissima+ bare land shrub.Soils under shrub canopy had significantly higher contents of organic matter,total N and available K,compared to those in open spaces,and presented obvious “fertile island” phenomenon.Shrub types had significant effects on soil salinity,and different cluster effect existed in soils under different shrubs.The heterogeneity of soil resources resulted from a large number of factors,including climate,soil environment,height and extent of shrub canopy,stemflow,existance of other ground cover plants,and so on,many of which were mutually interactive.

Soil moisture dynamics under broad-leaved Korean pine forest in Changbai Mountains

YANG Hong^1,2;PEI Tiefan¹;GUAN Dexin¹;JIN Changjie¹;WANG Anzhi¹

2006, 17(04):  587-591 . 

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The located observation on the soil moisture dynamics under broad-leaved Korean pine forest in Changbai Mountains in 1990～1992 and 2003 showed that the seasonal variation of soil moisture content could be divided into five periods,i.e.,gathering water stage in spring,consuming water stage in arid season,holding water stage in rainy season,losing water stage in autumn,and relatively stable stage of soil moisture in winter-spring.By using standard deviation and variation coefficient,the vertical layers of soil moisture were divided into rapid change layer,active layer,and subactive layer.Correlation analysis was applied to analyze the relationships of moisture content among different soil layers and the correlation between soil moisture and precipitation in the same period.

Green space vegetation quantity in workshop area of Wuhan Iron and Steel Company

CHEN Fang;ZHOU Zhixiang;WANG Pengcheng;LI Haifang;ZHONG Yingfei

2006, 17(04):  592-596 . 

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Aimed at the complex community structure and higher fragmentation of urban green space,and based on the investigation of synusia structure and its coverage,this paper studied the vegetation quantity of ornamental green space in the workshop area of Wuhan Iron and Steel Company,with the help of GIS.The results showed that different life forms of ornamental plants in this area had a greater difference in their single leaf area and leaf area index (LAI),and the LAI was not only depended on single leaf area,but also governed by the shape of tree crown and the intensive degree of branches and leaves.The total vegetation quantity was 1 694.2 hm²,with the average LAI being 7.75,and the vegetation quantity of arbor-shrub-herb and arbor-shrub communities accounted for 79.7% and 92.3% of the total,respectively,reflecting that the green space structure was dominated by arbor species and by arbor-shrub-herb and arbor-shrub community types.Single layer-structured lawn had a less percentage,while the vegetation quantity of herb synusia accounted for 22.9% of the total,suggesting an afforestation characteristic of “making use of every bit of space” in the workshop area.The vegetation quantity of urban ornamental green space depended on the area of green space,its synusia structure,and the LAI and coverage of ornamental plants.In enlarging urban green space,ornamental plant species with high LAI should be selected,and community structure should be improved to have a higher vegetation quantity in urban area.To quantify the vegetation quantity of urban ornamental green space more accurately,synusia should be taken as the unit to measure the LAI of typical species,and the synusia structure and its coverage of different community types should be investigated with the help of remote sensing images and GIS.

Atmospheric particle-retaining capability of eleven garden plant species in Beijing

WANG Lei;GAO Shangyu;LIU Lianyou;HA Si

2006, 17(04):  597-601 . 

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With eleven garden plant species in Beijing as test materials,this paper determined the adhesion density of atmospheric particles on leaf surface,observed the micro-configurations of leaf epidermis,and measured the particle size distribution of the particles. The results showed that the particles were mainly adhered on upside leaf surface,and the adsorbed amount was about six times higher than that on underside leaf surface.The particle-retaining capability of the micro-configurations of leaf epidermis was decreased in the order of groove>vein+cell>cell>strip protuberance.The capability of particle-retaining was higher when the micro-configurations were denser and the fall between them was larger.The mean value and the mean percentages of PM_2.5 and PM₁₀ on upside leaf surface were 66.7% and 98.3%,while those on underside leaf surfaces were 43.4% and 92.9%,respectively.

Effects of soil phosphorus level on morphological and photosynthetic characteristics of Ageratina adenophora and Chromolaena odorata

WANG Manlian^1,2;FENG Yulong¹;LI Xin¹

2006, 17(04):  602-606 . 

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In this paper,a comparative study was made on the growth,morphology, biomass allocation,and photosynthesis of two invasive plant species Ageratina adenophora and Chromolaena odorata under five soil phosphorus levels,aimed to know how the test plant species acclimate to the changes of soil phosphorus level,evaluate which plant traits were associated with the invasiveness of the two species,and know whether the increased level of soil phosphorus could facilitate their invasion.The results showed that the two species had considerable phenotypic plasticity and ?phosphorus acclimation ability.At low phosphorus levels,their root mass ratio increased,which could enhance the nutrient capture ability,while at high phosphorus levels,their specific leaf area,maximum net photosynthetic rate,light saturation point,and chlorophyll and carotenoid contents per unit area were high,and the assimilative capacity and area increased,which could facilitate their carbon gain.A.adenophora had higher phosphorus acclimation ability than C.odorata.With the increase of phosphorous level,the relative growth rate,total biomass,branch number,leaf area index,and maximum net photosynthetic rate of the two species increased significantly,and most of the parameters were not decreased significantly under over-optimal phosphorus level.The two species could grow better under high phosphorus levels which were usually excessive and/or harmful for most native species,and enhanced soil phosphorus level might promote their invasion.At high phosphorus levels,the two invasive plant species might shade out native species through increasing their plant height,branch number,and leaf area index.The two species could maintain relatively high growth rate under high phosphorus levels in dry season when native plant species almost stopped growing.The ability that the invasive plant species could temporally use natural resources which native plant species could not use was also associated with their invasiveness.

Germination strategy and ecological adaptability of Eragrostis pilosa

LI Xuehua^1,2;LI Xiaolan^1,2;JIANG Deming¹;LIU Zhimin¹

2006, 17(04):  607-610 . 

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The study on the germination strategy of Eragrostis pilosa under different storage and environmental conditions showed that freshly collected E.pilosa seeds had a stronger innate dormancy.Chilling and dry storage for 4 months had no obvious effect on releasing from dormancy,while longer time storage could facilitate seed maturation.The seeds could germinate either in light or in darkness,and stronger light was in favor of germination.The optimal temperature for germination was 28 ℃,while higher or lower temperature could result in the decrease of germination.The germination percentage of seeds under changed temperature (16 to 28 ℃) was higher than that under constant temperature (28 ℃),but with no significant difference.The critical amount of rain for seed germination was about 10 mm,and the germination percentage and duration all increased with increasing rainfall.E.pilosa had two germination strategies,i.e.,quick germination and dormancy for more than one year.Based on the seed morphological characters and germination strategies,it could be concluded that E.pilosa had a persistent soil seed bank.

Spatial heterogeneity of land use intensity

WANG Guojie^1,2,3;LIAO Shangang²

2006, 17(04):  611-614 . 

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To approach the spatial heterogeneity of human disturbance is of significance in researching the dynamics of land cover change,especially the characteristics of its directional structure.Jinjiang City is a “hot” region of land use change in Fujian Province,and the land has experienced intense human disturbance.This paper studied the spatial heterogeneity of land use intensity and human disturbance in this city in 1989～2001,with systematic grid sampling method and geostatistics in application.The results revealed that there was an obvious spatial heterogeneity of human disturbance in the study area,especially the directional structure of NE-SW caused by the traffic line from QingyangAnhai.Human disturbance was grown in the whole area,and the administrative centers served as the growth poles.Because of the associated influence of traffic lines and administrative centers,human disturbance was of a pole-axis structure.

Effects of different recover and restoration measures on soil quality in Karst rocky desertification region

LONG Jian¹;LI Juan²;JIANG Xinrong¹;DENG Qiqiong¹;LI Yangbing¹

2006, 17(04):  615-619 . 

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The soil quality of karst rocky desertification region were taken as case studies with four different recover and restoration measures for 13 years long-term fixed site harnessing in Guizhou Province,and plant diversity and soil fertility over different measures were investigated.The results showed that the plant diversity was the lowest,soil feritilities and ecosystem environment were the poorest in the control land with no restoration measure.The plant diversity rised evidently and the soil quality restorated to some degree in the measure of changing into a Zanthoxylum bungeamum woods(Measure A) and the measure of changing into multispecies woods (Measure B).The diversity of auxiliary community were resumed to the best degree and soil quality were resumed to the best degree in measure of closed forest(Measure C).The plant diversity was higher and soil quality was best in measure of secondary forest(Measure D).Therefore,the proper biological measures and the essential engineering measures are effective to recover the serious degradation ecosystem in Karst mountain of Guizhou Province.

Distribution characteristics of organic matter and total nitrogen in sediments of Lake Wuliangsuhai

SUN Huimin,HE Jiang;LU Changwei;GAO Xingdong;FAN Qingyun;XUE Hongxi;TIAN Huijuan

2006, 17(04):  620-624 . 

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Lake Wuliangsuhai is one of the representative inland freshwater lakes in grassland areas of China,and its shrinking and eutrophication is becoming more serious.The study on the ecological and environmental effects of the shrinking and eutrophication revealed that the total nitrogen (TN) content in the surface sediment of the lake had an obvious differentiation both in longitudinal and in latitudinal direction,and had a significant correlation with organic matter content.The mean C/N ratio of the sediment ranged from 12.07 to 19.95,which meant that the organic matter was mainly come from the hydrophytes of the lake,and the eutrophication of the lake was mostly caused by its internal load.Both TN and organic matter had a clear grainsize effect in different fractions of grain sizes of surface sediment,and their contents in IV (<63 μm) were as 3.1～7.6 and 2.5～8.0 times as those in I (>250 μm),respectively.

Responses of soil temperature in wetland ecosystem to air temperature and their effects on CO₂ emission

SONG Changchun^1,2;WANG Yiyong¹

2006, 17(04):  625-629 . 

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Through two years located field observation,this paper studied the responses of marsh soil temperature to air temperature and the effects of soil temperature on CO₂ emission from marsh soil-vegetation system,and calculated the seasonal variation of CO₂ emission.The results showed that from the beginning of thawing,an increasing trend of soil temperature was exerted by the change of air temperature,and there was a significant exponential correlation between soil temperature in root layer and air temperature (R²=0.94,P<0.01).Despite of the decreased responses of soil temperature to air temperature with increasing soil depth,the CO₂ emission from marsh soil-vegetation system was strongly exponentially correlated with soil temperature in root layer (R²=0.84,P<0.01).An improved model equation was used for calculating the mean CO₂ efflux from marsh soil-vegetation system during the growth season in 2003,and the calculated CO₂ efflux was 664.5±213.9 mg·m^-2·h^-1,approaching the value of located field observation (634.0±227.7 mg·m^-2·h^-1),indicating that this model equation was effective to evaluate the CO₂ emission from marsh during growth season.

Effects of nitrogen application rate and its basal-/top-dressing ratio on spatio-temporal variations of soil NO₃^--N and NH₄⁺-N contents

MA Xinghua¹;YU Zhenwen¹;LIANG Xiaofang¹;YAN Hong²;SHI Guiping²

2006, 17(04):  630-634 . 

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Under high-yielding cultivation condition,this paper studied the spatiotemporal variations of soil NO₃^--N and NH₄⁺-N contents as affected by different nitrogen application rate and its basal-/top-dressing ratio,and calculated the apparent budget of soil nitrogen at different growth stages of wheat. The results indicated that compared with split application,applying all fertilizer nitrogen at jointing stage decreased the soil NO₃^--N content and apparent surplus of soil nitrogen before jointing stage,and decreased the nitrogen leaching to deeper soil layers. Applying fertilizer nitrogen at flagging stage had no significant difference with split application in soil NO₃^--N content,but increased soil NH₄⁺-N content.Applying fertilizer nitrogen at maturing stage increased the soil NO₃^--N content in 0～60 cm and 0～20 cm layers. In comparing with applying 240 kg·hm^-2 of fertilizer nitrogen at jointing stage,applying 168 kg·hm^-2 of fertilizer nitrogen at the same stage decreased the soil NO₃^--N and NH₄⁺-N contents at flagging stage,soil nitrogen deficit from flagging to maturing stage,and soil NO₃^--N content at maturing stage. The grain yield and its protein content had no significant difference among different treatments,but applying all 168 kg·hm^-2 fertilizer nitrogen at jointing stage induced the highest grain protein content.

Effects of soil root-growing space on root physiological characteristics and grain yield of sorghum

ZHANG Yongqing^1,2;MIAO Guoyuan²

2006, 17(04):  635-639 . 

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In this paper,soil culture was conducted on the Experimental Farm of Shanxi Agricultural University,with the sorghum planted in cylindrical nylon bags to confine the space of root growth but allow the passthrough of water and nutrients,aimed to study the effects of soil rootgrowing space on the root physiological characteristics and grain yield of sorghum.The results showed that the confinement of root growth space decreased the plant height,leaf area,SOD and POD activities in flag leaf,total root length,root absorbing area,dry weights of root and aboveground part,nutrient uptake and grain yield,but increased the activity of root and its active absorbing area.Fertilization stimulated the root growth under space stress,increased the activity of root and its absorbing area,promoted nutrient uptake,and thus,increased grain yield while decreased the detrimental effects derived from the confine of root growth space.

Effects of nitrogen and phosphorus fertilization and sowing date on dynamic changes of grain sedimentation value during grain filling stage of spring wheat

ZHAO Xiulan^1,2,3

2006, 17(04):  640-646 . 

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In this paper,a field experiment with three genotypes of spring wheat was conducted in Harbin in 2002 to investigate the effects of nitrogen (N) and phosphorous (P) fertilization rate and sowing date on the dynamic changes of grain sedimentation value (GSV) during their grain filling stage.The results showed that the dynamic changes of GSV with the days after anthesis fitted third-order convex curve,and the effects of genotypes and environmental factors on the dynamics of GSV formation could be expressed by the characteristic variables of the curve equation.Different genotypes had different GSV,and the dynamic change shapes in the accumulation velocity curves of GSV were responsible for its mature values.With the increase of N fertilization rate,the GSV and the peak values of its dynamic curves decreased in high protein-rich gluten and low protein-poor gluten genotypes but increased in high protein-medium gluten genotype,and the dates corresponding to the peak values were advanced in high protein-rich gluten genotype while postponed generally in high protein-medium gluten and low protein-poor gluten genotypes.With the increase of P fertilization rate,the GSV and the peak values of its dynamic curves increased generally in high protein genotype but decreased in low protein genotype,and the dates corresponding to the peak values were all postponed in the three genotypes.A rational ratio and rate of N and P fertilization was the key to elevate the GSV during grain filling stage.Under moderate rainfall,the interaction between temperature and sunlight was the predominant factor affecting the dynamic formation of GSV in different genotypes,and rainfall was the second factor.≥10 ℃ accumulated temperature was the most sensitive factor affecting the dynamic formation of GSV because the enhancement of ≥10 ℃ accumulated temperature could elevate the GSV in the three genotypes.In general,high protein genotype was more easily affected by N and P fertilization rate and meteorological conditions than low protein genotype.

Physiological effects of air temperature and sink-source volume at milkfilling stage of rice on its grain quality

TAO Longxing¹;WANG Xi^1_;LIAO Xiyuan¹;SHEN Bo²;TAN Huijuan¹;HUANG Shiwen 1

2006, 17(04):  647-652 . 

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This paper studied the grain quality and Q-enzyme activity of three rice varieties and their combinations as affected by air temperature and sinksource volume.The results showed that at the early stage of milk filling,the grains of fully milk filling under high temperature had a higher chalkiness,lower transparency,and lower rate of white rice.Compared with the grain of early-rice,that of late rice had higher gel consistency and transparency,and higher rate of white rice.Planting rice at early-or late season had no significant effect on the amylose and protein contents of rice grain.Leaf-cutting to limit source decreased grain quality markedly,while grain-thinning to decrease sink improved grain quality significantly.

Effects of shading on squash seedlings’ morphological and photosynthetic physiological characteristics

QIN Shuhao;LI Lingling

2006, 17(04):  653-656 . 

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The study of squash seedlings’ morphological and photosynthetic physiological characteristics under different shading showed that under 60% light transmittance,their relative growth rate,net photosynthetic rate (P_n),stomatal conductance (G_s),transpiration rate (EVAP),water use efficiency (WUE),saturation steam pressure (MBR),apparent quantum yield of photosynthesis (AQY),and chlorophyll contents were higher,while the intercellular CO₂ concentration (C_i) was lower,compared with those under 20% light transmittance and CK.The seedlings under 60% light transmittance had a higher light saturation point (1 125 μmol·m^-2·s^-1) but a lower light compensation point (15.2 μmol·m^-2·s^-1).Squash seedlings under lower light intensity could endure lower concentration of CO₂,while those under higher light intensity could endure higher concentration of CO₂.Under 60% light transmittance,the malondialdehyde (MDA) and praline (Pro) contents were the lowest,while the peroxidase (POD) and catalase (CAT) activities were the highest.

Effects of shading on the growth,development and grain yield of summer maize

ZHANG Jiwang;DONG Shuting;WANG Kongjun;HU Changhao;LIU Peng

2006, 17(04):  657-662 . 

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Under field condition,this paper studied the effects of shading on the growth,development,and grain yield of summer maize varieties ND108 and YD13.The results showed that shading decreased maize yield significantly,and the effect was differed with different shading period and intensity.With a shading intensity of 50% and 90%,the grain yield of ND108 and YD13 was decreased by 67.5% and 79.4%,and 82.9% and 86.7% when shading at flowering-maturing stage,and by 34.1% and 55.3%,and 47.2%,65.7% when shading at joining-flowering stage,respectively.Shading at seedling-joining stage had a relatively smaller effect,with the grain yield decreased by 16.9% and 24.5%,and 18.9% and 24.3%,respectively.Shading had a larger effect on YD13 than on ND108,and the effect of shading period was larger than that of shading intensity.Under shading,the growth and development of maize was retarded,and the effect was increased with increasing shading intensity.Shading at joining-flowering stage affected spike differentiation significantly,reflecting in the marked decrease of the numbers of silks and tassels,and the effect was also larger on YD13 than on ND108.The leaf and plant growth was restrained significantly when shading at seedling stage and at flowering-maturing stage.

Canonical correlations of light and temperature with yield and quality characters of F₁ ecological populations of hybrid rice

ZHOU Hongkai^1,2;GUO Jianfu¹;LI Huashou²;WU Tian¹;ZHANG Jianzhong¹

2006, 17(04):  663-667 . 

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In this paper,field experiment was conducted to analysis the canonical correlations of light and temperature with the yield and quality characters of F₁ ecological populations of 54 hybrid rice breeds.The results showed that the yield and quality characters of the populations were significantly correlated with the accumulated temperature,effective accumulated temperature,extreme temperature difference,and sunshine length through the growth period of hybrid rice.The first canonical correlation coefficient (λ₁) between the light and temperature during vegetative growth stage and the yield characters was 0.9975,with the canonical information accounted for 99.96% of the total canonical information,leading to 99.50% of yield variation.Light and temperature affected the yield of hybrid rice mainly through their effects on the total and effective numbers of grains’ spikelet and its fertility.In this aspect,accumulated and effective accumulated temperature played a determinative role during vegetative growth stage,while extreme temperature difference and sunshine length were the key factors during reproductive growth stage.As for the quality characters of hybrid rice,light and temperature mainly affected the percentage of polished to head rice,and in this aspect,accumulated and effective accumulated temperature played a determinative role before filling stage,while extreme temperature difference and sunshine length were the key factors after this stage.

Effects of elicitors on aphid growth and development and on specific genes expression in wheat

ZHU Chuanshu;ZHAO Huiyan

2006, 17(04):  668-672 . 

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This paper studied the development duration,adult weight,and mean relative growth rate (MRGR) of aphid Schizapis graminum,and the specific genes expression in wheat variety 98-10-30 (Triticum aestivum) after treated with different elicitors.The results showed that needling penetration,aphid feeding and BTH application could shorten the development duration of the aphid and decrease its adult weight,but had no significant effect on aphid MRGR.Different elicitors induced different specific genes expression in quality and quantity.The mRNA of PDF1.2 was increased significantly after aphid feeding,while there was no expression after applying BTH.Aphid feeding and BTH application increased the mRNA of BGL2,but no expression was observed in the control and after needling penetration.The induced resistance had some effects on aphid growth and development,and the response induced by aphid feeding had some similarities but significant differences to that induced by mechanical wounding and BTH application.It could be concluded that the response of aphid to elicitors was a special resistance,and there existed some overlaps or differences between it and mechanical wounding and SAR (systemic acquired resistance).

Geostatistical analysis on temporal patterns of Chilo suppressalis population

YUAN Zheming;LI Fangyi;HU Xiangyue;ZHANG Zhongfei

2006, 17(04):  673-677 . 

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The geostatistical analysis on the temporal patterns of Chilo suppressalis population in the Dingcheng District of Changde City,Hunan Province from 1960 to 2001 indicated that the data series of the total number and the numbers of 1^st generation,2^nd generation,and over-wintering larvae from year to year displayed better autocorrelation and prediction,especially for the total number,whose autocorrelation range and degree were 10.3 years and 91.1%,respectively.The data series of generation to generation,1^st generation year to year,3^rd generation year to year,and over-wintering larvae year to year all demonstrated an obvious long-term tendency,especially for over-wintering larvae.A remarkable cycle of 3 generations in one year was observed in the population of generation to generation.Omitting certain generation or interposing over-wintering larvae only resulted in a slight change in the autocorrelation of the whole data series generation to generation,while planting system,food,climate,and natural enemies played more important roles in regulating the population dynamics rather than the base number of the larvae.The basic techniques of geostatistics applied in analyzing the temporal dynamics of C.suppressalis population were outlined.

Functional groups of natural enemies and their temporal-spatial dynamics in jujube orchard intercropped with herbage

SHI Guanglu^1,2;LIU Suqi¹;ZHAO Lilin³;CAO Hui¹;MIAO Zhenwang⁴;LI Dengke⁵;FENG Jin⁵;ZHANG Jiugang⁵

2006, 17(04):  678-684 . 

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In this paper,an investigation was made on the temporal-spatial dynamics of the functional groups of natural enemies in the jujube orchard 2.5 km west of Taigu (112°8′E,38°9′N,780 m elevation),Shanxi Province in 2002,aimed to work out an effective strategy to control the pests there.In this orchard,four management modes were applied,i.e.,intercropping herbage combined with integrated pest management (IPM),intercropping combined with conventional pest management (CM),intercropping with no pest management (NM),and non-intercropping (CK).The results indicated that the total number of natural enemies in IPM,CM and NM was 187.99%,151.82% and 210.03% higher than CK,respectively,and the recovery and reconstruction rates as well as the average breadth and overlap indices of two dimensional temporal-spatial niches of the functional groups were higher in intercropping modes than in CK.The average diversity index of the functional groups in intercropping modes was significantly bigger than that in CK,but the fluctuation of the diversity standard error of the functional groups was significantly smaller (P<0.05).The fluctuation trends of the dominance,diversity,and evenness of functional groups had a significant correlation (P<0.01) with those of species.These results showed that intercropping herbage in jujube orchard was favorable to the conservation,proliferation,and making use of natural enemies.The natural enemy’s community in jujube orchard intercropped with herbage was more stable than that without intercropping,and the numbers and functions of the functional groups were differed with different management modes and different stages.Among the functional groups of natural enemies,ladybirds had a stronger ability of recovery,while spiders and parasitoids were weaker.It was feasible to use functional groups instead of species to study the natural enemy’s community in jujube orchard.

Arbuscular mycorrhizal fungal growth on citrus roots and its correlations with soil available phosphorus content and phosphatase activity

WU Qiangsheng;XIA Renxue;ZOU Yingning

2006, 17(04):  685-689 . 

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In 2004,a field investigation was made on the mycorrhizal infection rate,spore density,soil available phosphorus content,and soil phosphatase activity in the Guoqing No.1 (Citrus unshiu)/trifoliate orange (Poncirus trifoliata) and Guoqing No.4 (C.unshiu)/trifoliate orange (P.trifoliata) plantations,aimed to approach the correlations between the arbuscular mycorrhizal fungal growth on citrus roots and the available phosphorus content and phosphatase activity in rhizosphere soil.The results showed that the annual variation of mycorrhizal infection rate and spore density in the test plantations was in “Λ” shape,while that of soil available phosphorus content and neutral phosphatase activity was in “V” shape.The mycorrhizal infection rate was significantly positively correlated with spore density (P<0.01),and negatively correlated with soil available phosphorus content (P<0.01),indicating that higher spore density and lower soil available phosphorus content could accelerate the mycorrhizai infection on citrus roots.The pore density was significantly negatively correlated with soil available phosphorus content (P<0.01) while positively correlated with soil total and neutral phosphatase activity (P<0.01),suggesting that soil available phosphorus could inhibit the increase of spore density,while soil total and neutral phosphatase activity could stimulate it.The mineralization of soil organic phosphorus in citrus plantations was mainly depended on soil neutral phosphatase activity.

Endophytic bacteria isolated from wheat and their antifungal activities to soil-borne disease pathogens

QIAO Hongping;HUANG Lili;KANG Zhensheng

2006, 17(04):  690-694 . 

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In this paper,endophytic bacteria (EB) were isolated from the roots,stems,leaves and immature seeds of wheat at its different growth stages.The EB populations in fresh wheat tissues reached 5.0×10⁵ CFU·g^-1 on average,with a significant difference among different tissues,growth stages and fields.The EB count was 7.8×10⁵ in wheat roots,4.8×10⁵ in stems,3.2×10⁵ in leaves,and 2.8×10⁵ CFU·g^-1 in immature seeds,and was estimated as 3.1×10⁵,5.7×10⁵ and 7.0×10⁵ CFU·g^-1 at seedling, elongation and filling stages,respectively.A total of 51 antifungal EB isolates were trapped by the wheat pathogenic fungus Gaeumannomyces graminis,and 45 by Rhizoctonia cerealis.Among them,78 isolates showed antifungal activities in vitro.A total of 23 isolates from roots (6),stems (7),leaves (9) and immature seeds (1) were highly inhibitory to the mycelial growth of G.graminis var.tritici,with the diameters of their inhibition zone exceeding 10 mm.The other twenty isolates from different plant parts were also active against R.cereali.It was revealed that higher ratios of EB isolates with high antifungal activities were found in leaves,as compared with stems,roots and immature seeds.

Toxicity and oviposition-deterrence of Vitex negundo extracts to Plutella xylostella

YUAN lin;XUE Ming;LIU Yuqing;WANG Hesheng

2006, 17(04):  695-698 . 

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This paper studied the toxicity of dichloromethane-petroleum ether-and methanol extracts from Vitex negundo seed and leaf to the 2nd and 4th instar larvae of Plutella xylostella,and the oviposition-deterrence effects of these extracts to P.xylostella adults.The results indicated that among the 6 extracts,dichloromethane extract from seed had the highest toxicity to the 2nd and 4th instar larvae,followed by dichloromethane extract from leaf,and methanol extract from leaf had the lowest toxicity.The toxicity of dichloromethane extract from seed to the 2nd and 4th instar larvae was as 2.62 and 3.09 times as that of methanol extract from leaf,respectively,and the toxicity of dichloromethane extract from seed to the 4th instar larvae was as 0.73 times as that of phoxim.The methanol extract from leaf and the dichloromethane extract from seed had higher oviposition-deterrence to P.xylostella adults.At the concentration of 4 000 mg·L^-1,they had a longer residual efficacy,with the oviposition-deterrence ratio being 60.6% and 55.2% after treated for 24 h,and 50.9% and 46.1% after treated for 72 h,respectively.

Allelopathy of decomposing pepper stalk on pepper growth

HOU Yongxia¹;ZHOU Baoli¹;WU Xiaoling¹;FU Yawen¹;WANG Yueying² 

2006, 17(04):  699-702 . 

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With decomposing pepper stalk as test material,this paper studied its allelopathy on the growth of pepper plants.The results showed that after 60 days of decomposition,the decomposed pepper stalk could decrease the plant height,stem diameter,dry weights of above-and underground biomass,leaf area,and chlorophyll content of pepper plants by 0.0374～0.0646,0.0020～0.0097,0.0050～0.0355 and 0.0916～0.3584,0.0016～0.0251,and 0.0043～0.0242 respectively.These inhibitory effects were enhanced after 120 days of decomposition,but the difference with CK was not significant.The root vigor and its SOD,POD and CAT activities of pepper plants were decreased,while the MDA content and relative conductivity were increased with the increasing concentration of decomposed pepper stalk and with the prolong of treating time.The allelopathic effects of decomposed pepper stalk on the physiological indices of pepper root activity ranged from 0.0163 to 0.6507,which was significantly higher than that of plant growth index.

Tolerance of Huso dauricus embryo at its different development stages to low temperature

YIN Jiasheng¹;KUANG Youyi¹;CHANG Yumei¹;WANG Jin²;ZHOU Changhai²;CUI Xishun²

2006, 17(04):  703-708 . 

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This paper studied the embryo hatching rate and larva survival rate of Huso dauricus when the embryo at its different development stages was exposed to low temperature for different durations.The results showed that the embryo at its yolk plug,narrow-opening,and neural block closing stages could not survive at 2～8 ℃ over 24 h.When exposed to 2～8 ℃ for 3 days,the hatching rate of embryo at its cleavage,early blastula,and mid gastrula stages was lower than 30%.Both the embryo hatching rate and the larva survival rate were higher than 70% when the embryo at its late blastula,early blastula,optic rudiment,tail bud,heart beating,and tail touching head stages was exposed to 5～8 ℃ for 3 days.The death rates of embryo and larva under low temperature were increased with time.There was a negative correlation between the exposure duration at low temperature and the embryo hatching rate (r=-0.8024) and larva survival rate (r=-0.8468) of H.dauricus.The embryo at its late blastula,early gastrula,and optic rudiment stages had a stronger tolerance at 5 ℃ for 10 h,with the embryo hatching rate and larva survival rate being higher than 70%.It could be concluded that there was a little difference in embryo hatching rate and larva survival rate of H.dauricus when the embryo at its some development stages was preserved at low temperatures at least for 10～15 days and at normal temperature (16～17 ℃).

Roles of forest management in global carbon dioxide mitigation

HU Huifeng;LIU Guohua

2006, 17(04):  709-714 . 

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This paper summarized the roles of current forest management measures,e.g.,reducing deforestation rate,increasing afforestation and reforestation,strengthening the management of nutrient fertilization,fire hazard,and disease and pest injury,and substituting fossils fuels with charcoal,in global carbon dioxide migration,and analyzed the advantage and insufficiency of China’s forest management.The authors indicated that the current forest ecosystems in China,mainly their vegetation carbon pool,played a smaller role of carbon sink in global carbon cycle,and thus,it was important to strengthen the tending of newly cultivated plantation and the management of fire hazard and disease and pest injury,and to increase the carbon sequestration of our forests.

Application of minirhizotron in fine root studies

SHI Jianwei¹;YU Shuiqiang¹;YU Lizhong¹;HAN Youzhi^1,2;WANG Zhengquan¹;GUO Dali³

2006, 17(04):  715-719 . 

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Due to the production,death,and decomposition of fine root,its turnover plays an important role in carbon allocation and nutrient cycling in terrestrial ecosystems.Some methods such as sequential root coring,compartmental flow model,and ingrowth core have been widely used in collecting root biomass data and estimating fine root turnover,but failed in monitoring the dynamics of fine root due to its simultaneous production and death.Minirhizotron is a nondestructive in situ method for studying the dynamics of fine root,which allows the simultaneous measurement of fine root growth and mortality.This paper reviewed the application of minirhizotron in fine root studies,with the focus on minirhizotron tube installation,image collection,data extraction,and calculation parameters.In a case study,the total fine root length,fine root length density per unit volume,fine root length density per unit area,fine root biomass density,and fine root production and mortality of Fraxinus mandshurica and Larix gmelini were calculated,and the results showed that minirhizotron method was feasible in studying the processes of fine root development,eclipse,death,and decomposition.The factors affecting fine root measurement and its precision mainly included the quality and quantity of tube installation,sampling interval and quantity,and analysis technique of images,etc.Soil texture,tube material,and disturbance of light on root were also the factors affecting the precision of the method.How to improve the measurement precision of minirhizotron would be the critical problem in future study.

Potential effects of elevated carbon dioxide on forest leaf-feeding insects

WANG Xiaowei^1,2;JI Lanzhu¹;WANG Guiqing^1,3;LIU Yan^1,2

2006, 17(04):  720-726 . 

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Elevated atmospheric CO₂ concentration may result in a decline of leaf nutritional quality (especially N) and an increase in some kinds of defensive secondary components such as phenolic compounds.The changes in tree phytochemistry,combined with the effects of elevated CO₂ per se,have a potential impact on leaf-feeding insects.This paper reviewed the effects of elevated CO₂ on the performance of leaf-feeding forest insects at individual level and community level.The elevated CO₂ per se had very little influence on the metabolism of insect.Over half of the tree-insect experimental system showed that under high CO₂,the performance of individual insect became poorer,while the others showed that insect had little or no response to the treatments.The direction and magnitude of the changes in insect performance could be affected by various factors,and the effects of treatments were strongly species-dependant.The magnitude of the changes in phytochemistry,the sensitivity and adaptive capacity of insect to poorer leaf quality,the differences in plant growth conditions and experimental methods,and the mediated effects of other environment factors,e.g.,soil NO₃^-,light,temperature,and O₃,were all closely related to the final performance of insect.But,the larvae’s consumption usually increased under enriched CO₂ treatment,which was widely thought to be a compensatory response for poorer plant quality.The experiments on forest community level found identically a reduction in herbivory,which was contrary to the results from small-scale experiments.The change of insect population and the true response of consumption by leaf-feeding forest insects under CO₂ enrichment environment remain unclear,and more field-based experiments need to be conducted.

Biological characteristics of alien plants successful invasion

SHI Gangrong¹;MA Chengcang^1,2

2006, 17(04):  727-732 . 

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How the traits of invasive plants determine their invasiveness is one of the major issues in invasion biology.Invasive plants usually have higher ability of adaptation,reproduction and dispersal,and thus,make them exploit a great diversity of habitats.Phenotypic plasticity and genetic differentiation are the two major strategies that alien invasive plants can adapt habitat heterogeneity.The polymorphism of invasive plants and the diversity of their dispersal way enable them occupying invaded habitat quickly,and dispersing with a far range.The breeding strategies that agamogenesis and amphigenesis can coexist and trade off according to the habitat and invasive stage can not only promote the invasive population erupted massively,but also directly affect the dispersal mechanism and regulate the genetic structure of the population.Efficient competition of resource utilization and interfering competition based on allelopathy make invasive plants more invasively.

Terrestrial plant stable carbon isotope composition and global change

ZHENG Shuxia^1,2;SHANGGUAN Zhouping¹

2006, 17(04):  733-739 . 

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Stable carbon isotope analysis is a rapid and reliable technique developed in recent years,and has been widely applied to reconstruct the sequences of atmospheric CO₂ concentration changes,clarify the hysteresis effect and junior effect of temperature and precipitation on tree growth,and distinguish the distributions of plants with different photosynthetic pathways.The water use efficiency (WUE) of different plant functional groups and the variations of plant WUE with tempo-spatial and climatic changes can be also indicated by determining plant carbon isotope composition.In this paper,the effects of environmental factors,e.g.,atmospheric CO₂ concentration,airtemperature, precipitation,and altitude on terrestrial plant carbon isotope composition were discussed,and the advances and applications of carbon isotope technique in global change research were summarized.Furthermore,the existing and disputed problems in carbon isotope analysis were discussed,and the future trends of carbon isotope technique in global change research were prospected,aimed to widen people’s knowledge and promote the development of this technique.

Migration and transformation of marine carbon and related chemical driving factors

ZHENG Guoxia^1,2;SONG Jinming¹;DAI Jicui^1,2

2006, 17(04):  740-746 . 

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The study showed that the migration and transformation of marine carbon had a close relation with the biogeochemical processes driven by various chemical factors.The growth and decline of nutrient concentration, pH,dissolved oxygen (DO),redox potential (Eh),SO₄^2-,and sulfur potential (Es) could change marine chemical environment,and thus,affect the migration and transformation of marine carbon.When the nutrient supply was adequate to the nutritional demand of phytoplankton,CO₂ was conveyed to deep sea through photosynthesis and organic matter oxidation,which caused the decrease of sea water P_CO2 and the increase of seaair CO₂ flux and organic carbon output,making the sea area as a CO₂ sink.But,the increasing acidification of marine environment caused by CO₂ dissolution and organic matter degradation brought about the solubility augmentation of carbonate in seawater.Moreover,the mineralization of organic carbon was coupled with the changes of DO,Eh,SO₄^2- and Es,and the deposition and burial process of carbon in sediments.In sea water body,high DO and high Eh accelerated the transformation from inorganic carbon to organic carbon,while in sediment,high SO₄^2- was adverse to the burial of organism with low DO and low Eh.

An approach to the theoretical meaning of ecological remediation of contaminated soil

LI Peijun;SUN Tieheng;GONG Zongqiang;LI Haibo;TAI Peidong

2006, 17(04):  747-750 . 

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The objectives of contaminated soil remediation are to transfer and transform the hazardous contaminants in soil,to eliminate and reduce their toxicity,and to restore or partly restore the ecological service function of soil.Since soil contamination is always a combined one,it is essential to use multiple methods to remediate contaminated soil.It is a tendency of soil remediation to use a uniform method,which aims to restore the ecological service function of soil by combining the restoration of internal function with external clean function.This paper discussed the concepts of ecological remediation of contaminated soil,and the ecological principles which should be obeyed in ecological remediation.Bioremediation is very important for ecological remediation,and the method organization should obey the principles of technique optimization.Remediation efficiency can be improved if self-clean function of soil system is strengthened and activated,together with external clean function.Ecological factor adjustment is essential for contaminated soil remediation,and also,a basic characteristic of ecological remediation and an important means for the enhancement of remediation efficiency.Ecological remediation should be harmonious, efficient,and stable.The final objective of ecological remediation is to restore the ecological service function of soil,in which,the evaluation of ecological remediation is the base.Ecological remediation theory shall play an important role in contaminated soil remediation.

Neighborhood comparison of Cryptomeria fortunei plantation by using different variables

HAO Yunqing¹;WANG Jinxi¹;WANG Qihe¹;LU Yuanchang²;ZHONG Fulin³;WU Xueyou³

2006, 17(04):  751-754 . 

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Neighborhood comparison is defined as the proportion of the nearest greater neighbors to a given reference tree measured by a certain variable.By this way,the dominant differentiation degree of individual wood could be measured well.In this paper,the variables DBH,biomass,canopy breadth,and tree height were used to make the neighborhood comparison of Cryptomeria fortunei plantation in Chongzhou forest farm.The results showed that the neighborhood comparison measured by DBH and biomass had a slight fluctuation range and the highest reliability.Nevertheless,due to the effects of various tree types,the neighborhood comparison measured by canopy breath and tree height was not as reliable as that measured by the former two variables.The average value of the neighborhood comparison measured by DBH and biomass was visibly higher than that by canopy breath and tree height,indicating that the differentiation degree of individual’s DBH and biomass was further greater than that of individual’s canopy breath and tree height.It was possible that increasing individual’s DBH to enhance its biomass,and thus,to achieve its predominance status among individuals’ competition was the main strategy of individual’s differentiation. Neighborhood comparison should also be taken as an instructive reference in modifying the spatial structure of stand.

Effectiveness of perforated film mulching on maize field in rainfall reception and soil ventilation

CHI Baoliang;HUANG Xuefang;ZHANG Dongmei

2006, 17(04):  755-758 . 

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To improve the light rain availability and soil ventilation in semi-arid area,this paper studied the effectiveness of perforated plastic film mulching on maize field.The results showed that perforated plastic film mulching had the benefits of receiving rainfall and supplementing soil moisture.Soil CO₂ content increased with increasing area of mulching,and was lower under perforated plastic film mulching than under common plastic film mulching.A negative correlation was observed between maize root vitality and soil CO₂ content.The maize yield under perforated film mulching was 8.98% higher than that under common film mulching .