Table of Content

25 January 1996, Volume 7 Issue 1

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Articles

Interspecific association and correlation of lime-broad leaved Korean pine forest on the northern slope of Changbai Mountain

Sun Zhongwei, Zhao Shidong

1996, 7(1):  1-5. 

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In this paper,^X2 and Pearson r formulae are used to study the interspecific association and correlation of lime-broad leaved Korean pine forest on northern slope of Changbai Mountain.The results show that there are 9 and 19 pairs of significantly associated species respectively in tree-and shrub layers.It is considered that from the view point of ecological meaning, whether it is significant or not,this association is a reflection of thedistinction of community habitat and the overlapping or seperation of niche width.Based on these results,a stable disposed model on ecological species groups in the community is established.

Distribution and accumulation pattern of nutrient element in Pinus sylvestriformis plantation ecosystem

Zou Chuming, Xu Wenduo, Hou Fenglian

1996, 7(1):  6-10. 

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The study shows that in tree layer,the nutrient content in various organs is in the order of needle>branch>root>bark>trunk,that in assimilated organ is in the order of N>K>Ca>P>Mg,and that in absorption organ is in the order of Ca>N>K>P>Mg In plantation ecosystem,the nutrient content is in the order of Soil>litter>herb layer>shrub layer>tree layer.The nutrient storage and its accumulation rate in tree layer are occupied by 88.79 % and 76.43% respectively.The absorption of N and P by plants in Pinus sylvestriformis ecosystem is more intensive.

Growth stage and classification of poplar shelterbelt

Zhu Jiaojun, Jiang Fengqi

1996, 7(1):  11-14. 

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Based on the characteristics of shelterbelt and the patterns of tree growth and shelterbelt structure, the growth of poplar shelterbelt can be divided into three stages,i.e,initial,middle(or fast growing)and protective maturing stages.Their quantitative indexes are determined by diameter discrete degree,protective maturity age and regeneration age.Corresponding management measures for each growing stage are given.

Effect of farmland windbreak on preventing rice lodging and yield reduction under violent tropical storm

Zhang Jinn, Kang Lixin, Ji Yonghua

1996, 7(1):  15-18. 

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Studies on the effect of farmland windbreak on preventing rice lodging and yield reduction under violent tropical storm in coastal regions of Jiangsu show that the percentage of rice lodging on the farmland with and without windbreaks is respectively 16.28% and 49.73%.If rice lodging is happened at the mildy stage,the thousand grains weight and the yield will be decreased by 13.24% and 14.32%,respectively.The yield reduction rate by rice lodging on the farmland with windbreaks is one third of that on the farmland without windbreaks.When the percentage of keeped trees of main windbreak is more than 90%,the resistance to rice lodging is the maximum,and the yield reduction rate from it is the minimum.

Network analysis of N, P and K flows in an agroforestry ecosystem

Han Boping, Wu Gang

1996, 7(1):  19-22. 

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A network analysis of N,P and K flows in Populus/Euramericana-Triticum sativum-Zea mays agroforestry ecosystem shows that the cycling index(CI)of N, P and K in the ecosystem is respectively 0.071,0.039 and 0.139,which is smaller than their cycling coefficiency(vCC),being 0.078,0.055 and 0.15,respectively.The total retention time of N,P and K in the ecosystem is 22.41,79.72 and 26.57 years,respectively.

Distribution characteristics of phosphorus in different media at upper reaches of Shandian River basin of north Hebei plateau

Sheng Xuebin, Sun Jianzhong, Dai Zhaohua

1996, 7(1):  23-26. 

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The analysis on the distribution of phosphorus in water,sediment,rock and soil at the upper reaches of Shandian River basin shows that the total P content in waters from same source is different from site to site,the maximum amount being 3.6 times higher than the minimum one. In various media,the content of total P is decreased in the order of soil>sediment>rock>water,and increased with increasing temperature.

Ecological basis of larger wheat ear formation

Lu Jingxian, Sheng Chengshi

1996, 7(1):  27-32. 

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In this paper,the development characteristics,young ear differentiation and its growth,and spike characters of three varieties of wheat are sin+died under different photo-temperature conditions.The feasible way of getting larger ear and more grain and improving wheat yield is also approached.The results show that different photo-temperature condition during wheat growing period induced by different seeding time makes the emerged date of various development stages of wheat and the lasted days of these stages much difference.In many cases,there exists a significant or very significant negative correlation between the lasted days of young ear differentiation and the mean air temperature and mead daylength.Different accumulated temperature is the main factor which induces the difference of the growth rate of young ear and that of the total number of spikelets per ear.In suitable wheat-planting area,it is practicable to introduce suitable varieties and appropriately shift their seeding to an earlier time to get larger ear and more grain and to improve wheat yield.

Influence of environmental conditions on genetic performance of cytoplasmic effects and nucleocytoplasmic interactions in hybrid rice Ⅳ. Effect of sterile cytoplasms on Polyamine metabolism in hybrid rice under different application rates of nitrogen

LinWenxiong, Lin Qunhui, Liang Yiyuan, Wu Zhiqiang

1996, 7(1):  33-38. 

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The results show that ADC activity,its metabolic product,putrescine content and ratio o f Spin/spd in nag leaves of hybrid rice exposed to nitrate stress were increased.The increment extent was different from nllcleocytoplasrnic systems an<l the interactions of them with environment concerned.Stable and positive effects of sterile-cytoplasms on ADC activities in the leaves were found.This implies that cytogenes may participate in the biosynthesis of ADC.Although the properties of negative or positive cytoplasmic effects on the enzyme activity in the leaves of test crosses were not altered by different conditions concerned.the extent of cytoplasmic effects in exposure of hybrid rice to nitrate stress was modified.Within Suitable physiological thresholds,positive cytoplasmic effects on ADC activities and grain yield of hybrid rice were pronounced by favorable environment in which putrescine accumulation within itS threshold proportionally promotes the growth of rice plant,while negatively cytoplasmic effects on them were observed under unfavorable conditions in which the rise in putrescine over its threshold relatively retards the growth of rice plant.This suggests that changes in polyamine biosynthesis and level may be an integral part of rice cytoplasmic responses in relations to environmental modulation.Additionally.the putrescine accumulation over its threshold with concomitant activation of IAA-oxidase and diamine-oxidase,and decreases of IAA concentrations was also observed.

Community variation on Songnen grassland after different burning time

Zhou Daowei, Zhang Baotian, Zhang Hongyi, Lu Jingmei

1996, 7(1):  39-43. 

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After early spring burning,the density,diversity and richness of grass species are increased and their evenness is decreased.but it is the contrary after later spring burning.Whether early or later spring burning, the height of the community is decreased,especially in the later burned plot.Burning can promote the growth vigour of Aneurolapidium chinense,which is more significant in the later burned plot. After burning,the leaf production of A.chinense is increaed,and the ratio of leaf to stem is the maximum in the later burned plot.The underground biomass of the community is increased in early burned plot,but decreased in later burned one.

Ecological and evolutionary morphological characteristics of Aneurolepidium chinense population

Lu Jingmei, Li Ji,ong, Hu Alin, Li Xiliang, Zhang Hongqin, Zhou Daowei

1996, 7(1):  44-48. 

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The analysis of succession and evolution patterns in single excellent species of Aneurolepidium chinense shows that the morphological structure of A.chinense on chernozem-type soil is simple, and that on saline-alkaline soil is complex,which consists of higher evoluted tissues,i.e.aerenchyma,protective tissue,parenchyma and conducting tissue etc.The results show that A.chinense on different soil types has significant intraspecific difference.

Persistence of Metarhizium anisopliae in soil and its potential in controlling Carposina nipponensis

Fan Meizhen, Li Zengzhi

1996, 7(1):  49-55. 

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The development process and quantitative dynamics of Metarhizium anisopliae in soil and its potential in controlling Carposina nipponensis are studied.The results show that the number of its colony forming units CFU is declined by more than 80% in all treatments after 62～82 days,and by more than 99% after 121～234 days.The half-life of initial inoculum are 28.5 and 23.8 days for conidia and 26.9 and 19.6 days for mycelia in sterile and non-sterile soil,respectively.With C.nipponensis cocoons containing larvae introduced 100 days after soil inoculation,their infection is compensated for the decline,and fungal recovery is 1000 times larger in 278 days than in 271 days after inoculation without cocoons.The mortality of C.nipponensis larvae introduced at different time after soil inoculation is remained by more than 90% by day 131,and is declined to 9.3% by day 237.C.nipponensis is not infected in untreated soil. In plot trials, 97～100% of larvae are killed with doses of 15,22.5,30 and 37.5 kg conidial preparation per hectare,and the rates of bored fruit are 2.7～5.0%.Pilot tests are conducted with an application rate of 22.5 kg·hm^-2in 670 hm² of north Shaanxi.The rate of bored fruit is reduced from 30% for untreated orchards to 2.4% for treated ones.

Area-restricted searching behavior of Harmonia acyridis imagoes

Zou Yunding, GengJiguang, Ji Jin, Meng Qinglei, Chen Gaochao, Sun Shihuang

1996, 7(1):  56-60. 

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The area-restricted searching behavior of both male and female imagoes of Harmonia axyridis is studied with methods developed by Nakamuta (1982).The total curved angle of searching trait of imagoes in 15 seconds after feeding is significantly larger than that in 15 secconds before feeding.Their food-searching efficiency is improved by frequent modification on search direction.The total distance between stops in 0～15, 15～30 and 30～45 seconds before feeding is significantly longer than that in 0～15, 15～30 and 30～45 seconds after feeding,respectively. The food-searching speed of imagoes in 0～15,15～30 and 30～45 seconds before feeding is 4～12 times quicker than that in 0～15, 15～30 and 30～45 seconds after feeding, which varies very little before feeding, but The longer the ime before the imagoes find the food,the quicker the searching speed is.The total rectilinear distance from food to stops is significantly longer and the searching area covered by the imagoes is 11～65 times larger before feeding than after feeding. It is believed that both male and female imagoes of Harmonia acyridis have area-restricted searching behavior.

Effect of morphological characters of rice varieties on functional response of Anagrus nilaparvatae

Lou Yonggen, Cheng Jiaan

1996, 7(1):  61-66. 

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A laboratory experiment is conducted to study the effect of morphological characters.of rice varieties on distribution of Nilaparvata lugens eggs on rice plants and the functional response of Anagrus nilaparvatae to it.The results show that for all rice varieties tested,the vertical distribution of N.lugens eggs on the plants could be divided into three types:mainly on the upper and middle parts of rice plant,mainly on the middle and lower parts of rice plant,and uniform distribution. The number of N.lugens eggs on the upper,rniddle and lower parts of rice plant is very significantly positively correlated with the relative height of leaf sheath back at the corresponding parts of rice plant.The functional response of the parasitoid to N. lugens eggs mainly distributed on the upper and middle parts of rice plant ZND40 is obviously stronger than that mainly distributed on the middle and lower parts of rice plant Z852.

Relationship between Allothrombium ignotum population density and eco-environment

Zhang Huijie, Li Jianshe, Gao Liangsheng, Liu Tianlu, Zhang Zhuomin

1996, 7(1):  67-71. 

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Studies on the relationship between A.ignotum population density and main ecological factors in cotton fields show that the population density is positively related to the lasted years of continuous cropping, but negatively related to the altitude and underground water level.The mite density in open cotton fields is significantly higher than that in mulched ones. The floating time of nymph in static water can be lasted 5.2 hours.For the eviposition of adults,the optimum soil moisture content is 12.5%.The killing power of different insecticides and their applicaition ways to larvae is in the order of spraying decamethrin>spraying omethoate>spraying dicofol>painting slow-releasing methoate on the stem.Developing irrigated cotton field.properly prolonging the lasted years of continuous cropping of cotton,and painting cottop stem during its growing period with insecticide to control aphid will have an important role in increasing A.ignotum population density.

Developmental trend of Dalian urban ecosystem

Shi Zuomin, Chen Tao

1996, 7(1):  72-76. 

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On the basis of systemic analysis of Dalian urban ecosystem,the developmental trends ofDalian urban ecosystem under three different strategies are studied by the methods of system dynamics and grey system,which provides a scientific basis and strategies on the planning and development of Dalian city.

Dynamic models of suburban landscape:a case study on Donling District of Shenyang

Xie Zhixiao, Xiao Duning

1996, 7(1):  77-82. 

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Based on the percolation theory and Markov process theory,and by the means of neutral model method,three suburban landscape dynamic models are established,which involve different physical and decision factors in Donling District of Shenyang.The simulated landscapes are compared with the practical ones,and the indices for evaluation include 1)multiple resolution goodness of fit method:2)number and mean size of patches,and 3)nearest neighbor probability.As the result of evaluation,the model integrating bothphysical and decision factors has the best effect.

Effect of intensive pen fish farming on aquatic vegetation and its ecological strategy

Yang Qingxin, Li Wenchao

1996, 7(1):  83-88. 

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The effect of intensive pen fish farming on surrounding aquatic vegetation is studied in East Taihu Lake.The affected area is larger than 1200 m in diameter.In the central area, Potamogelon maackianus is replaced by Hydrilla verticillata,Ceratophyllum demersum and Myriophyllum slicatum.spirogyra sp.becomes the dominant species. and its plants lost their value as fish food.Pollutant from the pens is the main cause of vegetation degeneration because the load of nitrogen and phosphorus is as high as 242 and 27.4 g·m^-2·yr^-1respectively in the pens (14.3 hm²). The obstacle-effect of the pens on windwave,water current and plant removal is another important cause of the degeneration of aquatic vegetation in the surrounding area. The total area of pen fish farming should be limited in the lake,and the pen should be small,well-distributed and moved its position every two or three years to prevent regional or whole lake eutrophication and vegetation degeneration.

Two-dimensional nonequilibrium sorption numerical model of radionuclide migration

Wang Jinsheng, Li Shushen, Wang Zhiming, Guo Zede, Chen Jiajun

1996, 7(1):  89-93. 

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With the view of further studying the migration pattern of radionuclide in porous media,a nonequilibrium sorption-desorption relation is coupled with hydrodynamic dispersion equation, and a nonequilibrium sorption numerical model is establishing.The method for the accluisition of sorption-desorption parameters used in the model is also given.In order to test the correctiveness of the established model and its computer code,the calculation concerned is made using the experimental data of⁸⁵Sr obtained in the field test site, and then compared with the calculated results of nuclide migration equilibrium sorption numerical model.The comparison shows that the established model can describe the actual situation of nuclide migration in a better way.

Translocation characteristics of trichloroethylene in saturated clays

Tang Changyuan, Shizuo Shindo, Hiroko Ohashi

1996, 7(1):  94-98. 

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The translocation characteristics of trichloroethylene(TCE)in saturated montmorillonoid and kaolin at different concentrations of NaCl are studied with column and batch experiments.The sorption isotherm shows that the partition coefficients(Kd)of TCE in montmorillonoid-rich clays are approximately 3～8 times larger than those in kaolin-rich clays.It is considered that montmorillonoid is an effective natural material available for environmental management.

Effect of low level SO₂ on carbohydrate metabolism of Picea asperata seedlings

KongFanxiang

1996, 7(1):  99-102. 

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Determinations of CO₂ uptake rate,sucrose content,activities of sucrose phosphate synthase (SPS),sucrose synthase(SS)and invertase and ATP/ADP value show that low level SO₂(200μg·m^-3)can instantaneously stimulate the uptake of CO₂ by Picea asperata seedlings.Compared with control,seedlings exposed to low level SO₂ show an obvious decline in SPS and SS activities and sucrose content and have a low value of ATP/ADP,which means that the physiological and biochemical processes of seedlings have been disturbed by SO₂ before the appearance of visible injuries.

Effect of chemical fertilizer sources on uptake and accumulation of Cd by Brassica chinensis cultivars

Wu Qiting, Chen Lu, Wang Guangshou, Tan Xiufang

1996, 7(1):  103-106. 

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The effect of defferent forms of N,P and K fertilizers on Cd uptake by Brassica chinensis and the defference betweenthe uptake and accumulation of Cd by the cultivars are studied with pot experiment.The results show that soil pH and conternts of soluble and exchangeable Cd are affected by different forms of chemical fertilizers.Cd content in shoots of five cultivars is in order of Chi-2≥Shijiu-19>Chi-29≥Teqing-80>Teping-60.Hydroponic culture experiment indicates that the uptake rate of Cd by unit root surface and its translocation rate to aboveground parts of Teping-60 are lower thant that of Chi-2.

Biological response of crops on enhanced solar ultraviolet radiation and its estimation

Zheng Youfei, Yang Zhimin, Yan Jingyi, Wan Changjian

1996, 7(1):  107-109. 

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Studies on the effects of enhanced solar UV radiation on the growth and physiology of soybean and wheat show that under natural conditions,the increase of UV radiation can inhibit the net photosyntetic rate and the growth of leaves,stems and roots of both tested crops.The decrease of biomass and yield is caused by the decline of transpiration and stomatal conductance of leaves.Estination of the crop response on the enhanced UV radiation shows that the mean error between fitting value and observed one is 0.30～8.56%.

Total oxygen consumption of sediment in shrimp ponds and its seasonal variation

SunYao

1996, 7(1):  110-112. 

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The total oxygen consumption of sediment in shrimp ponds and its variation with culturalareas and seasons are determined by on-the-spot determining method which is devised by ourselves.The results show that the determined values are varied with cultural areas and seasons.In areas polluted by bait remains,the values are obviously higher than those in unpolluted areas,which are increased with the increase of temperature and the lapse of cultural period,but there is no significant change in unpolluted area.The total oxygen consumption is ranged from 1.06 to 3.96g·m^-2·d^-1.