Table of Content

18 January 2006, Volume 17 Issue 01

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Articles

Distribution patterns of Fraxinus mandshurica root biomass,specific root length and root length density

MEI Li¹;WANG Zhengquan¹;HAN Youzhi^1,2;GU Jiacun¹;WANG Xiangrong¹;CHENG Yunhuan¹;ZHANG Xiujuan¹

2006, 17(01):  1-4 . 

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Employing soil core method,an investigation in Maoershan Experiment Station was made on the root biomass,specific root length (SRL),and root length density (RLD) of Fraxinus mandshurica plantation (17 yr) within a growth season in stand level.The results showed that the total root biomass was 1 637 g·m^-2,in which,living biomass accounted for 85%,and necrotic biomass was 15%.In the living biomass,coarse roots (5～30 mm in diameter) had the highest percentage (69.95%),followed by fine roots (<1 mm in diameter) (13.53%),medium roots (2～5 mm in diameter) (7.21%),and small roots (1～2 mm in diameter) (9.31%).Among the four diameter classes,fine roots had a higher SRL (32.20 m·g^-1),while coarse roots had a lower one (0.08 m·g^-1).The total RLD in living biomass was 6 602.54 m·m^-2 in stand level,among which,fine root accounted for 92.43%,and the others was less than 8%.Fine root biomass and RLD had a positive correlation with soil available nitrogen,while no significant correlation was found between SRL and soil available nitrogen.

Eco-anatomical characteristics of Sophora davidii leaves along an elevation gradient in upper Minjiang River dry valley

LI Fanglan^1,2;BAO Weikai¹;LIU Junhua^1,2;WU Ning¹

2006, 17(01):  5-10 . 

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This paper studied the ecoanatomical characteristics of Sorphora davidiileaves at the elevations of 1 650,1 750,1 850 and 1 950 m in the upper reaches of Minjiang River dry valley.The indices investigated were leaf length (LL),leaf width (LW),LL/ LW,leaf area,leaf thickness,leaf epidermal thickness,leaf palisade mesophyll thickness (P),leaf spongy mesophyll thickness (S),P/S,leaf cutin membrane thickness,leaf stomatal density and area,leaf epidermis cell density and area,and leaf pubescence length and density.The results showed that the leaves of S.davidii were elliptic,with an area 0.144～0.208 cm² and a thickness 171.58～195.83 μm.The mesophyll was significantly differentiated into palisade and spongy.The thickness of palisade mesophyll was 69.83～ 82.42 μm,that of spongy mesophyll was 62.00～80.67 μm,and P/S was 1.14～1.01.Upper epidermal thickness was 14.03～15.33 μm,while lower epidermal thickness was 13.88～16.17 μm.The stomatal density,stomatal area,epidermis cell density,epidermis cell area,pubescence length,and pubescence density were 13.71～15.02 mm^-2,249.86～280.43 μm²，160.54～178.43 mm^-2,557.43～626.85 μm²,186.51～260.99 μm,and 18.29～32.27 mm^-2,respectively.With increasing elevation,the leaf area,leaf thickness,palisade mesophyll thickness,spongy mesophyll thickness,stomatal area,epidermis cell area and pubescence density were increased,while cutin membrane thickness,epidermis cell density,pubescence length,and stomatal density were decreased.There was no significant difference in LL/LW,P/S,epidermal thickness and stomatal density along the elevation gradient.

Temporal-spatial characteristics of wind in tropical seasonal rainforest in Xishuangbanna of Yunnan Province

ZHANG Yiping¹;SONG Qinghai^1,3;YU Guirui²;SUN Xiaomin²;DOU Junxia^1,3

2006, 17(01):  11-16 . 

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Based on the observation data of wind speed and wind direction at different heights on the observation tower (70 m) in the tropical seasonal rainforest of Xishuangbanna,this paper analyzed the annual,seasonal and diurnal characteristics of wind.The results showed that the wind speed above crown canopy was stronger than that under canopy,and the diurnal and vertical change under the canopy was not obvious.From the height of 30 m to 50 m,the vertical change of wind speed was most remarkable,but its annual change was not obvious.Above 50 m,the change trend was opposite.Dry-hot season (March-April) had the strongest wind speed,followed by rainy season (May-October) and foggy-cool season (November -next February).The wind speed at daytime was stronger than that at nighttime.At daytime,wind speed was in order of morning>afternoon>noon.Wind direction had obvious diurnal characteristics,i.e.,leaning southeast wind at daytime and leaning west wind at nighttime.At daytime,the change trend of zero-plane displacement (d) was in order of morning>noon>afternoon,and the annual change range in the afternoon was wider and lower than that in the morning and at noon.The change trend of roughness length (Z₀) at daytime was opposite to that of d.The d value in the afternoon was obviously higher than that in the morning and at noon.

icroclimate edge effects of evergreen broad-leaved forest fragments in Jinyun Mountain:A preliminary study

YAN Ming^1,2,3;ZHONG Zhangcheng^1,2;QIAO Xiuhong⁴

2006, 17(01):  17-21 . 

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This paper studied the microclimate of continuous and fragmental evergreen broad-leaved forests in Jinyun Mountain by determining the horizontal gradient distribution of microclimate elements near forest edges.The results showed that there existed clear edge effects of microclimate in every edge of fragmental forests.The distinctions of maximum and minimum air temperature,photosynthetic active radiation,and minimum relative humidity between edge forest and interior forest were higher or greater,while that of maximum ground surface temperature was lower or smaller in dry season than in rain season.The edge effect was the smallest in the biggest fragmental patch,but the greatest in the smallest fragmental patch in interior forest.

Quantitative relationships of intra- and interspecific competition in Cryptocarya concinna

ZHANG Chi;HUANG Zhongliang;LI Jiong,SHI Junhui;LI Lin

2006, 17(01):  22-26 . 

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The monsoon evergreen broadleaved forest (MEBF) in Dinghushan Nature Reserve (DNR) has been considered as a zonal vegetation in lower subtropical China,with a history of more than 400 years.In this paper,the intra- and interspecific competition intensity in Cryptocarya concinna,one of the constructive species in MEBF in DNR was quantitatively analyzed by Hegyi single-tree competition index model.The results showed that the intraspecific competition intensity in C.concinna decreased gradually with increasing tree diameter.For C.concinna,its intraspecific competition was weaker than its interspecific competition with Aporosa yunnanensis.The competition intensity of interspecific competition with C.concinna followed the order of A.yunnanensis > Schima superba > Gironniera subaequalis > Acmena acuminatissima > Castanopsis chinensis >Syzygium rehderianum >Pygeum topengii > Blastus cochinchinensis >Sarcosperma laurinum > Pterospermum lanceaefolium > Cryptocarya chinensis.The relationship of the DBH of objective tree and the competition intensity between competitive tree and objective tree in the whole forest and C.concinna population nearly conformed to power function,while that between other competitive tree and the objective C.concinna tree conformed to logarithm function.There was a significantly negative correlation between the competition intensity and the DBH of objective tree.

Absorption and distribution of nitrogen from ¹⁵N labelled urea applied at core-hardening stage in winter jujube

ZHAO Dengchao¹;JIANG Yuanmao¹;PENG Futian¹;ZHANG Jin²;ZHANG Xu¹;JU Xiaotang³;ZHANG Fusuo³

2006, 17(01):  27-30 . 

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The study with pot experiment showed that at the rapid-swelling stage of winter jujube fruit,the percent of nitrogen derived from fertilizer (Ndff%) was the highest (10.64%) in fine roots,followed by new-growth nutritive organs.The absorbed urea-¹⁵N decreased in leaves and deciduous supers,and accumulated preferentially in root systems after harvest.The Ndff% in coarse roots was the highest (3.69%) before budding stage,while that in new-growth organs (new branches,deciduous supers,leaves and flowers) was the highest at full-blooming stage.The urea-¹⁵N applied at core-hardening stage mainly allocated in nutritive organs (leaves,deciduous supers,roots) in the first year,with the distribution rate 54.01% in root systems in winter,which was higher than that in branches (45.99%).The ¹⁵N stored in main branches changed drastically from post-harvest to budding stage.Main branches could be regarded as the ‘target organs’ of N storage,while coarse roots were the ‘longterm sink’ of N storage.The N reserve distributed preferentially in contiguity organs,and the distribution center changed with the growth and development of winter jujube in next spring.

Water balance of different density artificial Caragana microphylla shrubs in Horqin sand land

A Lamusa^1,2;CI Longjun¹;YANG Xiaohui¹;JIANG Deming²

2006, 17(01):  31-35 . 

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Employing water balance equation,this paper estimated the evapotranspiration of different density Caragana microphylla shrubs during their growing season.The results showed that during this season,the soil water content under artificial C.microphylla shrubs decreased with their increasing planting density.The average soil water content of 0.5 m×1 m and 1 m×2 m density artificial C.microphylla shrubs was below wilting humidity (1.55%)，while that of 2 m×2 m density and natural shrubs was kept above 1.60% which could meet the demand of shrubs growth.The evapotranspiration increased with increasing planting densities,being the highest (297.81 mm) in 0.5 m×1 m density artificial C.microphylla shrubs,which accounted for 97.90% of the total rainfall during growing season,and the lowest (279.71 mm) in 2 m×2 m density shrubs.By the end of growth phase,soil water content had a surplus of 24.49 mm.According to the soil water status and water balance theory,the appropriate planting density of C.microphylla shrubs in Horqin sand land should be 2 m×2 m.

Landscape pattern changes in urbanization of Pudong New District,Shanghai

WANG Yujie¹;LI Junxiang^1,2;WU Jianping¹;SONG Yongchang^1,2

2006, 17(01):  36-40 . 

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Urbanization is one of the most important anthropogenic impacts on natural landscape,while urban landscape pattern can reflect the urbanization process and its ecological consequences.In this paper,landscape metrics combined with gradient analysis was employed to analyze the landscape pattern changes of Pudong New District in Shanghai,based on the land use datasets derived from 1∶50 000 aerial photos of 1994 and 2000, respectively. The results demonstrated that the landscape pattern of Pudong changed dramatically in its ever-increasing urbanization.The land cover,which was dominated by agriculture in 1994,gradually transformed to urban land use,such as residential area,public facilities,and industry.The percentage of agriculture land use decreased from 71.45% to 41.32%,while the urban land use hold 18.2% in 1994 but rose to 41.9% in 2000.Synoptic landscape characteristics showed the increased patch numbers (from 4.08 to 28.65 ind.·km^-2),diminished areaweighted mean (from 24.43 to 1.75 km²),decreased aggregation index (from 98.31 to 95.09),and augmented landscape diversity and evenness,all of which demonstrated the higher landscape fragmentation and landscape heterogeneity induced by urbanization.The landscape pattern along the urbanrural gradient reflected the different urbanization stages,and the expanding urban frontier in different years in Pudong New District could be identified precisely with class-level landscape indices.The changes in landscape pattern along the transect suggested that the quantitative analysis of landscape dynamics,especially the landscape metrics combined with gradient analysis,could be a robust tool to study urban morphology,urban structure,and ecological consequences during urbanization.

Impacts of farmland consolidation on farmland landscape

DENG Jinsong;WANG Ke;LI Jun;XU Junfeng;SHEN Zhangquan;GAO Yurong

2006, 17(01):  41-44 . 

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Farmland consolidation is the act of regulating,improving,and comprehensively renovating the structure,quality,and layout of field,water,road,forestry,and village in the countryside in a certain area by means of administration,economy,law,and engineering techniques according to the goal and usage defined by land use planning,so as to improve farmland use rate and its output rate,to increase farmland area,and to achieve better productive,living,and ecological environment.Recently,farmland consolidation has been carried out all over the country,especially in its economy-developed regions.But,unscientific planning and unsuitable farmland consolidation engineering have negative effects on field ecological system.In this paper,based on the technology of GIS and RS,the basic theories and methods of landscape ecology and a compositive grading method were applied to analysis the dynamics of farmland landscape fragmentation in Tongxiang county.The results showed that the farmland landscape fragmentation in this county was strongly affected by consolidation.More attention should be paid to the protection of farmland landscape during consolidation,and to avoid or decrease the negative effects resulted from unscientific planning and unsuitable farmland consolidation engineering.

Application and verification of distributed model in simulating watershed evapotranspiration

LIU Jianmei^1,2;WANG Anzhi¹;DIAO Yiwei¹;PEI Tiefan¹

2006, 17(01):  45-50 . 

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Based on the conventional observed meteorological data during 1989～2000,a distributed model was employed to simulate the temporal and spatial distribution of the potential and actual evapotranspiration in the upper Zagunao watershed of Sichuan Province.Grids of 500 m and step of 1 d were used to describe the spatial and temporal heterogeneity and variability in the study area.The potential evapotranspiration was simulated by a deformation form of PenmanMonteith Equation,and a method for calculating actual evapotranspiration was proposed,with the underlying conditions considered.The results showed that the relative error of the normal annual evapotranspiration in the 12 years between the simulation and the calculation was 3.47%,with a reasonable temporal and spatial distribution.The research results provided an effective method for the distributed rainfallru noff model in simulating actual evapotranspiration.

Growth mechanisms of two ecotype Leymus chinensis populations in Songnen Plain

ZHOU Chan¹;YANG Yunfei²

2006, 17(01):  51-54 . 

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The study showed that there was a power function relationship between weight per tiller and density of two ecotype Leymus chinensis populations in Songnen Plain,and the b value in the function （-0.098～-0.272）was bigger than -1.The biomass and weight per tiller of the two populations increased with their increasing density and height,and the relationships between biomass and density,and between weight per tiller and height were significantly accorded with power or liner function.In the period of vegetation growth,the biomass and weight per tiller of the two populations had the smallest change speed,and the b value of grey-green ecotype （0.7872 and 0.0134） was smaller than that of yellow-green ecotype （0.8793 and 0.0222）.On the contrary,in the period of postfruiting vegetation growth,the b value of grey-green ecotype （0.8048 and 0.0303）became bigger than that of yellow-green ecotype （0.7796 and 0.0258）.It was suggested that the two ecotype L.chinensis populations did not reach environment capacity in the sampling field.They kept on growing during the whole growth period,with the same growth pattern,and grey-green ecotype had a stronger potential capability of growing.

Fractal features of soil particle size distribution in degraded sandy grassland during reclamation and enclosure

WEN Haiyan^1,2;FU Hua¹;ZHAO Halin²

2006, 17(01):  55-59 . 

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Based on the analysis of 42 soil samples from the grassland reclaimed and enclosed different years,this paper studied the fractal features of soil particle size distribution and the relationships between fractal features and soil properties.The results showed that the fractal dimension of soil particle size distribution in 0～30 cm soil layer ranged from 2.378 in reclaimed land to 2.588 in non-grazed enclosure,while that in 0～15 cm soil layer decreased from 2.441 in grazed grassland to 2.387 after 20 years of reclamation,and increased to 2.588 after 11 years of enclosure.No significant changes were found in fractal dimension in 15～30 cm soil layer between reclamation and enclosure.Statistic analysis indicated that the fractal dimension could objectively reflect soil texture,mainly the content of clay,and then silt content.There existed a remarkable quantitative correlation between fractal dimension and soil physical,chemical and biological properties,which meant that the fractal dimension could be used as a comprehensive and quantitative index in evaluating soil properties and grassland degradation degree.

Characteristics of references between GSCC and CST for Semi-Luvisols

YU Dongsheng;SHI Xuezheng;WANG Hongjie;DU Guohua;GONG Zitong

2006, 17(01):  60-64 . 

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In this paper,the references between Genetic Soil Classification of China (GSCC) and the Chinese Soil Taxonomy (CST) for GSCC-Semi-Luvisols were conducted,and their quantitative and spatial distribution characteristics within CST were studied,based on the 1∶1 M Soil Database of China,which consists of 1∶1 M digital soil map,soils profiles attribution database and soil reference system of China.Being a reference system for converting soil names in GSCC into those in CST,ST and WRB,respectively,Chinese Soil Reference System was a computerized retrieving system jointly developed by the experienced scientists of pedology and computer science.The comparison fields and laboratory investigation data of their soil profiles with diagnostic horizons and characteristics related in the target soil classification systems,and 2 540 typical soil species names corresponding in CST,ST and WRB systems were determined,respectively,which were selected from Soil Attributes Database because of their complete sets of attribute data.Finally,the system and reference database were established.“GIS linkage based soil type” method linked the records in the Soil Reference Database to the Soil Spatial Database.In this method,all records of soil profiles in Soil Reference Database as well as their soil reference name in other classification systems were allocated one by one onto corresponding soil type polygons in Soil Spatial Database on the GIS platform,according to the principles of soil type identity and similarity,parent material identity and likeness,and the location of soil profiles relative to linked target polygons.Area statistcs of all soils were conducted based on the polygons.The results showed that GSCC-Semi-Luvisols was a type of GSCC soil with a total area of 427 843.1 km²,which could be sorted to 4 CST Orders, i.e.,Luvisols (51.3%),Cambosols (35.2%),Isohumosols (10.7%) and Anthrosols (2.8%),and further into CST 22 Groups and 38 Subgroups.All dark grey forest soil,superficial gleyed black soil,and leached dry red soil of GSCC subgroups could be sorted to Calcaric HapliGelic Cambosols,Pachic Argi-Udic Cambosols and Typic Ferri-Ustic Luvisols of CST subgroups,respectively,and all grey cinnamon-like soil,calcareous grey cinnamonic soil and dry cinnamon soil could be sorted to Typic Ustic Cambosols.Making the reference was so complicated that there was no one to one reference relationship among other soils.The analysis of the area ratios and standard deviations of a certain GSCC soil classified by CST showed that the lower the unit for reference,the easier the reference would be.The results of this study were of high reference value to proper reference GSCC and CST,and to the application and development of CST.

Mathematical simulation of stomatal regulation involving root-sourced signaling ABA under soil drought condition

YANG Yuanyan^1,2;GUO Anhong²;An Shunqing²;LIU Gengshan²

2006, 17(01):  65-70 . 

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A stomatal conduction model consisting of root water uptake model and stomatal control model under the participation of rootsourced signal ABA was developed in this paper,which considered the root water uptake effect function and root length density distribution function during root-sourced signal production.This model was used to simulate the course of maize stomatal conduction controlled by the root-sourced signal in field.The results showed that owing to the considering of the influence of root water uptake effect function and root length density distribution in soil profile,this model could more accurately depict the intensity of root water uptake,the ABA concentration produced in root system,the root ABA concentration in different soil layers and in xylem,and the controlling process of plant stomatal regulation by rootsourced ABA.

Combined effects of enhanced UV-B radiation and doubled CO₂ on tomato growth and its fruit quality

LI Fangmin¹;CHEN Yiping²;WANG Xunling^1,3;YUE Ming¹

2006, 17(01):  71-74 . 

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The study on the effects of 8.40 kJ·m^-2 UV-B radiation,700 μmol·mol^-1 CO₂ concentration,and their combination on tomato (Lycopersicon esculeutum) growth and its fruit quality showed that under enhanced UV-B radiation,the plant height,fresh weight,dry weight,photosynthesis rate,water use efficiency,and contents of total chlorophyll,chlorophyll a,chlorophyll b,soluble protein,ascorbate acid (Vitamin C) and lycopene were decreased,which resulted in the deterioration of tomato fruit quality.Doubled CO₂ concentration alone accelerated tomato growth,and accordingly,ameliorated its fruit quality.Under the combined effects of enhanced UV-B radiation and doubled CO₂ concentration,tomato growth and its fruit quality were not significantly different from the control.It was suggested that the positive effects of doubled CO₂ could lighten and counteract the negative effects of UV-B radiation under combined treatment of enhanced UV-B radiation and doubled CO₂ concentration.

Grainfilling characters of different genotype winter wheat under nitrogen fertilization in semihumid area of south Loess Plateau

LI Ziyan¹;LI Shiqing^1,2;WU Weimo^1,2,3;SHAO Ming’an²;ZHANG Xingchang²

2006, 17(01):  75-79 . 

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A field experiment was conducted in the south part of Loess Plateau with 632 mm precipitation each year.Three genotypes winter wheat 9430,Xiaoyan No.6 and Shang188 were used as test materials to study their grainfilling characters under two nitrogen application levels (0 and 90 kg·hm^-2).The results showed that genetic difference was the main factor affecting grainfilling characteristics,while nitrogen fertilization had a less effect.There were significant differences among genotypes in the duration of maximum grain filling rate (GFRmaxD),active grain-filling period (D),and the days reaching to the maximum grain-filling rate (GFRmaxGD).For Shang188,Xiaoyan No.6 and 9430,the GFRmaxD was 17.20,14.15 and 14.13 d,D was 29.00,26.40 and 2688 d,and GFRmaxGD was 28.14,23.90 and 23.89 d,respectively.All the parameters of Shang188 were significantly bigger than those of 9430 and Xiaoyan No.6,while those of the latter two had no significant difference.There was an interaction between nitrogen fertilization and genotype,but the effect of nitrogen fertilization on the three parameters was relatively small.1000 kernel weight had a significant positive correlation with GFRmaxD,GFRmaxGD and D,suggesting that the three parameters were the main factors affecting grain weight.

Community structure and its dynamics of pest,predatory and neutral insects ina jujube ecosystem

SHI Guanglu^1,2;ZHAO Lilin³;LIU Suqi¹;CAO Hui¹;LI Shiyou⁴;PIKE Bruce⁴

2006, 17(01):  80-86 . 

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An investigation on the insects in the jujube ecosystem in Taigu District of Shanxi Province,Northern China showed that more species and individual numbers of pest,predatory and neutral insects were found on the tree than on the ground.The ratio of the species and individual numbers of predatory and neutral insects to those of pest insects fluctuated from year to year.Homoptera,Coleoptera and Lepidoptera were the dominant groups of pest insects,while those of predatory insects were Coleopteran, Hemiptera, Diptera and Hymenoptera.The vertical distribution of the community structure of the same or different subcommunity was different in different seasons,as was the case of the same or different subcommunity in the same season.The diversity indexes of pest,predatory and neutral insects fluctuated with seasons,and the populations of predatory and neutral insects had a significant correlation (r=0.9833,P<0.05) with the fluctuation of pest insects.There was also a significant correlation between the pest,predatory and neutral insects in different stratums of tree canopy,especially in the middle stratum of tree canopy (r=0.9887,P<0.01).

Numerical characteristics of insect community structure in five stored export products along Yangtze River in Jiangsu Province

GUO Jianbo¹;DU Yuzhou¹;HAN Zhenchong²;LU Yajuan²;GU Jie²

2006, 17(01):  87-90 . 

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This paper investigated the dominant species of insect communities in five stored export products along Yangtze River in Jiangsu Province.With the indexes species richness,ecological dominance,community diversity and evenness,the numerical characteristics of insect community structure in the stored products were analyzed,and the similarity of the communities was also analyzed.By the method of hierarchical cluster analysis,the numerical classification was made,and the communities were grouped into 4 groups.The insect communities in stored willow and feather products were in the same group,while those in other stored products were grouped into 3 groups.Except that in woodwork products,the insect community structures in other stored products,especially in leather products,were not rational.

esponses of spring wheat to elevated CO₂ and their effects on Sitobion avenae aphid growth,development and reproduction

CHEN Fajun^1,2;WU Gang^1,2;GE Feng¹

2006, 17(01):  91-96 . 

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The study on the responses of spring wheat (Triticum aestivum) potted in open-top chamber to elevated CO₂ (542.1±24.8 and 738.8±25.7 μl·L^-1 vs.382.4±24.8 μl·L^-1) and their effects on Sitobion avenae aphid growth,development and reproduction showed that elevated CO₂ was advantageous for spring wheat growth.In treatments 550 and 750 μl CO₂·L^-1,the plant height during May 5～June 14 increased by 2.80%～14.92% and 6.30%～17.56%,and leaf area per plant during April 30～June 19 increased by 5.68%～50.52% and 6.14%～83.45%,respectively,compared with CK.The DC₅₀ and DC₇₅ were brought forward about 0.39 and 0.53 d for treatment 550 μl CO₂·L^-1,and 0.90 and 1.02 d for treatment 750 μl CO₂·L ^-1, respectively.Moreover,the stem,leaf,ear and above-ground biomass also had some increase under elevated CO₂.Compared with CK,a significant increase of ear length (0.56% and 3.20%) and grain number per ear (12.5% and 18%),but a significant decrease of 1000-grain dry weight (2.23% and 6.34%) were observed for treatments 550 and 750 μl CO₂·L^-1,respectively.With increasing CO₂,the chemical constituents in ear,such as glucose, disaccharide, amylose and TSCs/nitrogen ratio increased significantly,while fructose,trisaccharide and total nitrogen decreased significantly.CO₂ elevation shortened the preoviposition duration and longevity of S.avenae,and increased the number of offspring per female aphid and mean relative growth rate (MRGR).Compared with CK,the MRGR increased 33.26% in treatment 550 μl CO²·L^-1,and 74.34% in treatment 750 μl CO₂·L^-1. Furthermore,there was a significant correlation between the MAGR of S.avenae and the TSCs/nitrogen ratio of spring wheat ear.

Kriging prediction of soil zinc in contaminated field by using an auxiliary variable

JIANG Yong¹;LI Qi^1,2;ZHANG Xiaoke^1,2;LIANG Wenju¹

2006, 17(01):  97-101 . 

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In this study,two kriging methods using an auxiliary variable, i.e.,ordinary cokriging (OCK) and ordinary kriging combined with regression (OKR) were used for the interpolation of soil zinc (0.1 mol·L^-1 HCl extractable Zn) in a 17.6 hm² field at the vicinity of a metal manufacturer in southern suburb of Shenyang,China.A total of 36 measured data of soil Zn content at the depth of 10～20 cm (subsoil Zn) was selected as target variable,72 measured data at the depth of 0～10 cm (topsoil Zn) as auxiliary variable,while other 36 measured data of subsoil for validation.The two interpolation methods were evaluated for the suitability of estimating the spatial distribution of soil Zn by using an auxiliary variable.The results showed that OKR gave better results than OCK or ordinary kriging (OK).The theoretical model obtained from OKR exhibited higher coefficient of determination and lower residual sums of squares than that from OCK or OK.The prediction accuracy of soil Zn was increased by 4% with OKR than with OK.The map of soil Zn obtained with OKR was quite similar with that obtained with OK,by using 72 measured Zn data.However,no advantages were found between OCK and OK.It was suggested that OKR was an effective way to estimate the distribution of soil heavy metals by using auxiliary variables.

Effects of Cd on rape growth and antioxidant enzyme system

WANG Xingming;TU Junfang;LI Jing;WANG Lilong;LIU Dengyi

2006, 17(01):  102-106 . 

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he study with pot experiment showed that the fresh weights of rape plant and leaf decreased with increasing Cd concentration,and the decrease of leaf fresh weight resulted in the decrease of whole plant fresh weight.The permeability of cell membrane and the content of MDA increased with increasing Cd concentration.When the concentration of Cd was 20 mg·kg^-1,compared with the control,cell membrane permeability and MDA content were increased by 29.68％and 15.19％ respectively,and there was a significant correlation between these two indices.When the Cd concentration was 5 mg·kg^-1,the contents of chlorophyll a,b and a+b reached their peaks,and were 23.97%,33.63% and 26.45% higher than the control,respectively.Cd stress had no significant effect on carotenoid content.The sensibility of the pigments to Cd stress was chlorophyll b> chlorophyll a>chlorophyll a+b> carotenoid,and that of protective enzymes was POD>CAT>SOD.The IC50 of test physiological indices suggested that rape could only grow well on the soil with <5 mg·kg^-1 Cd.

Relationships between population characters of Undinula vulgaris (Copepoda) and environment in the East China Sea

XU Zhaoli

2006, 17(01):  107-112 . 

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Based on the data of four seasonal oceanographic censuses in 1997～2000 in the East China Sea (23°30′～33°N,118°30′～128°E),this paper discussed the relationships between the ecological characters of natural Undinula vulgaris population and its environment in the Sea,with the data of 1979～1980 compared.The results showed that there was a very clear seasonal change of the dominance,abundance,and occurrence frequency of U.vulgaris,i.e.,autumn (0.09,556 ind·100 m^-3,93.69％)>summer (0.03,86 ind·100 m^-3,68.49％)>winter (0.02,42 ind·100 m^-3,53.85％)>spring (0.01,16 ind·100 m^-3,34.35％).As a dominant species of pelagic copepods in the Sea, U.vulgaris showed its predominance mainly in autumn.The percentage of U.vulgaris in the total abundance of pelagic copepods was 2.31% in spring,4.80% in summer,3.80% in winter,and 9.90% in autumn,while its occurrence frequency was the highest in autumn and the lowest in winter.Comparing the results of this study with the data of 1979～1980,the importance of U.vulgaris in pelagic copepods in the Sea was decreased in spring,summer and autumn,but increased in winter,which might be related with the global warming in winter.The main environmental factors affecting U.vulgaris abundance were the bottom water factors that closely related with the warm current in the ocean.Because of its sensibility to low temperature and coastal water mass, U.vulgaris could be used as a good indicator of warm current,and,as a good food for fishes,this species plays an important role in marine fishing in the middlesouth part of the East China Sea.

Dynamics of dissolved organic carbon (DOC) leaching in meadow marsh soil and related affecting factors

YANG Jisong^1,2;LIU Jingshuang¹;YU Junbao¹;WANG Jinda¹;ZHOU Wangming^1,2;QIN Shengjin^1,2

2006, 17(01):  113-117 . 

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In this paper,an incubation test with soil columns was carried out for 35 days to study the dynamics of DOC leaching from the organic layers (2～13 cm) of two meadow marsh soils,and the correlation of DOC release with soil respiration,NH₄⁺ formation,and leachate pH.The results showed that in the first week,DOC release presented a fast decrease,and then held on a steady level,which could be well described by one order exponential equation (R²>0.96,P<0.05).During 35 days incubation,the cumulative release of DOC from two test soils was 210.9 μg C·g^-1 and 506.58 μg C·g^-1,and the cumulative emission of CO₂ was 67964 μg C·g^-1 and 455.54 μg C·g^-1,respectively.It was suggested that in the course of incubation,the lower DOC release might be related to the microbial carbon limitation because of the greater CO₂ production rate.A significantly positive correlation was found between DOC release and NH₄⁺ formation (r_Ⅺ=0.886,P<0.05;r_Ⅻ=0.972,P<0.01),while no significant correlation was observed between DOC release and leachate pH.Multiple regression analysis showed that the nitrogen mineralization potential of meadow marsh soil was the main factor affecting DOC production.

Characteristics of heavy metals enrichment in algae and its application prospects

LU Kaixing^1,2;TANG Jianjun²;JIANG De'an²

2006, 17(01):  118-122 . 

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Using algae to bio-remedy heavy metals-contaminated waters has become an available and practical approach for environmental restoration.Because of its special cell wall structure,high capacity of heavy metal-enrichment,and easy to desorption,algae has been considered as an ideal biological adsorbent.This paper briefly introduced the structural and metabolic characteristics adapted for heavy metals enrichment of algae,including functional groups on cell wall,extracellular products,and intracellular heavy metals-chelating proteins,discussed the enrichment capability of living,dead and immobilized algae as well as the simple and convenient ways for desorption,and analyzed the advantages and disadvantages of using algae for bioremediation of polluted water,and its application prospects.

Effects of enhanced UV-B radiation on physiological metabolism,DNA and protein of crops:A review

LI Yuan;HE Yongmei;ZU Yanqun

2006, 17(01):  123-126 . 

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Ozone depletion in stratosphere has led to the increase of solar UV-B radiation reaching to the earth surface,which would affect crops to various extents.This review dealt with the effects of enhanced UV-B radiation on the physiological metabolism,DNA damage and protein content of crops.Enhanced UV-B radiation could increase crops’ flavonoid content but decrease their chlorophyll content and photosynthesis,induce gene change,and result in DNA damage and change of protein content.

Research advances in behavioral ecology of penaeid shrimps Ⅰ.Behavior of penaeid shrimps

ZHANG Peidong¹;ZHANG Xiumei¹;LI Jian²

2006, 17(01):  127-130 . 

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The behavioral ecology of penaeid shrimps has been studied extensively in many countries due to their special ecological habit and important position in sea water aquaculture.This paper reviewed the recent literatures on the behavior of penaeid shrimps,including feeding,locomotion,defense,mating,spawning,molting,burrowing and emergence,with the differences of the behavior in different habitats discussed.The existing research problems,and the study directions of penaeid shrimps in the future,e.g.,the feeding strategies and mechanisms in various circumstances,the selection and adaptability to environmental factors,and the practical application of penaeid shrimps behavior theory,were put forward.

Agricultural environment quality of China and its improving countermeasures

ZENG Xibai;YANG Zhengli

2006, 17(01):  131-136 . 

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This paper analyzed the present status of China agricultural water and soil environment.It was indicated that the agricultural water environment in this country was more serious,with the affected area being approximately 20% of the total farmland,and 5% of it being severely affected.More attention should be paid to the pollution of agricultural chemicals in soil environment.The impacts of industrial wastes,urban sewage and garbage,agricultural chemicals,and soil erosion on agro-environment were discussed,with the impact degree of these factors analyzed.The major problems in China agricultural environment melioration were presented,related researches and major countermeasures in this country and developed countries were reviewed,and relevant measures and suggestions on improving the agricultural environment quality of China were put forward.

Adaptation strategies of seed germination and seedling growth to sand dune environment

ZHU Yajuan^1,2;DONG Ming¹;HUANG Zhenying¹

2006, 17(01):  137-142 . 

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Sand dune plants possess many adaptation strategies to withstand sand environment,e.g.,some desert plant seeds are dormant when matured,which helps them to escape from unfeasible environment conditions and be preserved as seed bank.The seed germination and seedling establishment of psammophytes need moderate sand burial,while excessive burial will inhibit seed germination and seedling emergence.Seeds without germination in deeper sand are in enforced dormancy,and form soil seed bank.Sand dune plant seedlings could tolerant finite sand burial by increasing the number of nodes per culm and elongating internodes.When the seedlings are partially buried,they could survive through the maintenance of photosynthesis organism.Once sand burial exceed the threshold of the plant,seedlings growth will be restrained and the growth ability even permanently lost.Other factors such as salt spray,insect herbivory,and lack of soil nutrients also affect seed germination and seedling establishment.The precipitation in desert and sand land is unpredictable and irregular.Sand erosion leads roots be exposed to the air and dehydrated to die.However,seedlings of some desert plant have the ability to tolerate desiccation for a period of time after germination.Once there is rain,the seedlings will rivive.

Research advances in carbon balance in subtropical hilly red soil

WENG Boqi;WANG Yixiang

2006, 17(01):  143-150 . 

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Carbon balance is becoming a hotspot in global change and geo-science studies.The subtropical hilly red soil area in China is an important production base of foodstuffs and tropical and subtropical economical crops and woods,and also,is very important in carbon balance research because of its special ecological and geographic characters.This paper discussed the significance of subtropical hilly red soil in carbon balance,and reviewed the related research advances and main results,including plant,litterfall,soil carbon storage,and soil respiration etc.The integrative research methods of carbon balance were summarized,and some issues and development directions in carbon balance research were discussed .

Ecological control effects of Litchi chinensis-Desmodium intortum complex plant ecosystem on litchi pests

OUYANG Gecheng;YANG Yueping;LIU Deguang;XIONG Jinjun;HUANG Mingdu

2006, 17(01):  151-154 . 

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An investigation on the community structure and dynamics of litchi pests and their natural enemies in constructed Litchi chinensis-Desmodium intortum complex plant ecosystem and single L.chinensis ecosystem showed that the total amount of litchi pests in the complex plant ecosystem was 61.27% of that in the single ecosystem in whole year,and only 50.45% in May,the key time for fruit development,which suggested that there was an interaction between D.intortum and L.chinensis.D.intortum and L.chinensis had a few common pests,but many common natural enemies.D.intortum florescence in winter provided shelter and substitutive food for the natural enemies of pests to survive in the extreme environmental conditions in winter.L.chinensis florescence was on the heel of D.intortum florescence,which provided better conditions for the natural enemies to survive and multiply.During florescence and fruit development stages of L.chinensis (from March to June),the predator/prey ratio in complex plant system was 4.22,2.34,2.2 and 20.63 times of that in single plant system in March,April,May and June,respectively,indicating the good control effect on pests of L.chinensis.

Effects of dissolved compounds on photodegradation of mefenacet in water

CHU Mingjie¹;YUE Yongde^2,3;HUA Rimao³;TANG Feng³

2006, 17(01):  155-158 . 

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The study with high-pressure mercury lamp illuminating showed that after illuminated for 15 min,NO₂^- and NO₃^- quenched the photolysis of mefenacet,and NO₃^- with a concentration ratio 10∶1 (mass) had the most obvious effect,its quenching rate being up to 53.3%.Halogen ions inhibited the photolysis of mefenacet by “weight atom effect”.When the concentration ratio of I^- was 10∶1,the quenching rate was 76.9% after illuminated for 15 min.Surfactants Nongru 500,Nongru 404,Nongru 601 and Nongru 603 had different effects on the photodegradation of mefenacet.At concentration ratios 1∶5 and 1∶1,only Nongru 404 showed a weak photosensitive effect,while in the other cases,all the four surfactants had photoquenching effects.Among the four herbicides benthiocarb,bensulfuron,alachlor and chlorsulfuron,only bensulfuron at low concentration ratio (1∶10) accelerated the photolysis of mefenacet,with a photosensitive proportion of 18.2% after illuminated for 25 min.Aerified N₂ could accelerate the photolysis of mefenacet,and the half-life was shortened from 7.14 min to 6.70 min without aerifying N₂.

Effects of rare earth elements on soil fauna community structure and their ecotoxicity to Holotrichia parallela

LI Guiting;JIANG Junqi;CHEN Jie;ZOU Yunding;ZHANG Xincai

2006, 17(01):  159-162 . 

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By the method of OECD filter paper contact,this paper studied the effects of applied rare earth elements on soil fauna community structure and their ecological toxicity to Holotrichia parallela in bean field.The results showed that there were no significant differences between the treatments and the control in soil fauna species,quantity of main species,and diversity index.Urgent and chronic toxic test showed that the differences between the treatments and the control were not significant.It was suggested that within the range of test dosages,rare earth elements had little ecological toxicity to Holotrichia parallela,and did not change the soil fauna community structure.

Intraspecific differences in physiological responses of different wheat cultivars to enhanced UV-B radiation

HE Lilian;ZU Yanqun;LI Yuan;WU Yusheng

2006, 17(01):  163-165 . 

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In this paper,field studies were conducted to determine the potential of alterations in physiology,and the intraspecific differences in sensitivity of 10 wheat (Triticum aestivum) cultivars to enhanced UV-B radiation.The supplemental UV-B radiation was 5.00 kJ·m^-2,simulating a depletion of 20% stratospheric ozone in Kunming area.The results showed that six of 10 tested wheat cultivars showed significant changes in total chlorophyll content,among which,chlorophyll a was strongly reduced,but chlorophyll b was reduced to a lesser extent,leading to a decrease in chlorophyll a/b ratio.The effects of UV-B on MDA and flavonoid contents also showed intraspecific difference.The MDA content of 5 cultivars was significant increased,while that of 2 cultivars was decreased.Four cultivars had significantly increased flavonoid content,but the flavonoid content in 2 cultivars was significantly decreased.The changes of chlorophyll and flavonoid contents were significantly correlated with the content of MDA (r=-0.78，P<0.01 and r=-0.75,P<0.05 respectively).There was a correlation between flavonoid and antiUV-B radiation of wheat.