Loading...
Welcome to Chinese Journal of Applied Ecology! Today is Share:

Table of Content

    25 November 1999, Volume 10 Issue 6
    Articles
    Population structure of tropical montane rainforest on Wuzhi Mountain of Hainan
    Zhu Xuelei, An Shuqing, Zhang Lixin, Wang Zhengfeng
    1999, 10(6):  641-644. 
    Asbtract ( 1610 )   PDF (996KB) ( 537 )  
    The analysis on the age structure of six dominant populations Syzygium araiocladum, Nephelium topengii,Schefflera octophylla, Memecylon ligustrifolium, Mallotus oblongifolius and Diospyros hainanensis in the montane rainforest on Wuzhi Mountain of Hainan Province show that all the populations had an increasing structure and were in developmental stage. The development of these populations would determine the future formation type of the tropical montane rainforest. Static life table analysis and spectral analysis on Syzygium araiocladum show that an obvious periodic fluctuation existed in the population, and that its regeneration was strongly related to forest gaps.
    Species diversity and population dynamics of plants on deciduous broad leaved forest slash at Wuling Mountain
    Guo Quanshui, Wang Deyi, Feng Tianjie
    1999, 10(6):  645-649. 
    Asbtract ( 1447 )   PDF (884KB) ( 529 )  
    Based on five years consecutive located observations at permanent plots, the species diversity, community evenness and population dynamics of regenerated seedlings,herbs and shrubs before and after clearcutting of the deciduous broad leaved forest at Wuling Mountain were studied by using Shannon Wienner's species diversity index and the evenness index. The species diversity and evenness indexes of tree seedlings on the slash were higher in4 years after cutting than before cutting, Populus davidiana not existed in the uncut forest stands quickly propagated, while Pinus tabulaeformis existed in the uncut forest stands was absent on the slash. The species diversity and evenness indexes of shrubs increased on the slash. Weigela florida and Lespedeza bicolor were the dominant species. Rubus crataegifolius, which was not dominant at the beginning,increased rapidly in the later period, and became dominant on the slash. The species diversity and evenness indexes of herbs peaked in the third year, and began to decrease in the fourth year. The herbaceous plants were classified into 8 types, based on their population dynamics before and after forest cutting. The light demanding species developed well, and the shade enduring species gradually disappeared,which were the obvious characteristics for herbaceous populations.
    Ecological feature and floral analysis of Juglans mandshurica community in Huoshan Mountain of Shanxi Province
    Bi Runcheng
    1999, 10(6):  650-656. 
    Asbtract ( 1442 )   PDF (1017KB) ( 823 )  
    The community of Juglans mandshurica in the Huoshan Mountain of Shanxi Province was investigated by the methods of quatrat and plotless sampling. The importance values of 34 tree species were calculated, and the community ecological features of the community in species composition,appearance and vertical structure were analyzed.The composition of the families and genera of 187 vascular species,the lifeform composition and the types of distribution regions, as well as the species diversity and ecological dominance of 23 communities consisting of 26 tree species and 20 shrub species in23 plots were also analyzed. The interaction between the J.mandshurica community and its environment was expounded,which could provide a scientific basis for community management and resource evaluation and utilization.
    Research and development of planting trees and killing oncomelania expert system in Hubei Province
    Song Xiaochun, Lu Zaihan, Deng Hong, Liu Lide, Tang Wanpeng
    1999, 10(6):  657-660. 
    Asbtract ( 1431 )   PDF (407KB) ( 486 )  
    With the technique of pick up database management, the database of basic factors in the “planting trees and killing oncomelania” system is constructed, by which, all data can be searched, filtered and sorted conveniently. Based on the constructed mathematical models, the dynamic data linking is realized by some Visual Basic functions. Moreover, the connection of data, information and graphics is realized by dynamic data exchange. By the expression of object oriented knowledge, the systemic knowledge class hierarchy is set up, and the corresponding reasoning mechanism is improved. According to the result of mathematical processing of factors relative to intended beach development, site classification and site quality evaluation are completed, and the optimized ecological patterns and technological measures are recommended. The economic, ecological and social effects can be analyzed and evaluated. Some commutative user machine interfaces satisfied GUIstandards are also designed.
    Autointoxication of Chinese fir
    Lin Sizu, Huang Shiguo, Cao Guangqiu, Huang Zhiqun
    1999, 10(6):  661-664. 
    Asbtract ( 1592 )   PDF (488KB) ( 514 )  
    Studies on the autointoxication of Chinese fir show that the aqueous extracts of surface soil, leaf litter, half decaying leaf litter, fresh leaf, branch, bark and root in pure Chinese fir plantation and their polyvinyl pyrrolidone k30 (PVP) solutions affected the seed germination of Chinese fir, Raphanus sativous and water convolvulus. At high concentration of aqueous extracts, seed germination was significantly inhibited, while with decreasing concentration, the inhibitory effects got weaker, disappeared and even turned into stimulating effects. The aqueous extracts added PVPsignificantly weakened the inhibitory effect, and exhibited enhancement effect at low concentration.
    Biodiversity of shrub community in desert steppe and steppe desert on Erdos plateau
    Li Xinrong, Zhang Xinshi
    1999, 10(6):  665-669. 
    Asbtract ( 1733 )   PDF (863KB) ( 987 )  
    This paper studied the distribution characteristics of shrub community diversity with environmental gradients and the influence of environmental factors on community diversity. The results show that the shrub community diversity was decided by the spatial arrangement of community,especially,the composition of herb layer.From desert steppe to steppe desert,the shrub community diversity was gradually decreased. Among the ecological factors such as geological coordinates,annual average temperature,coldest and hottest monthly temperature,annual evaporation,sun radiate percentage,wind velocities and sand storm days,water gradient was the main factor affecting biodiversity.Nevertheless,the influence of water gradient was not at a significant level,because the effect of overgrazing and human's destroying on shrub community was far greater than that of water gradient change.
    Evaluation on sustainable and highly efficient utilization of agricultural resources in red and yellow soil region of China
    Hou Xiangyang
    1999, 10(6):  670-672. 
    Asbtract ( 1504 )   PDF (287KB) ( 413 )  
    Based on the analysis on the relationship between the sustainability and the high efficiency of regional agricultural resources utilization,this paper established an evaluation indicator system of sustainable and highly efficient utilization of agricultural resources in red and yellow soil region of China. Using this evaluation system, 22 typical counties with medium and low productivity in the region were evaluated.
    Main features of soils with different soilmass structural patterns in Leling jijithus producing area
    Sheng Xuebin, Sun Jianzhong, Liu Yunxia, Chen Qingmu, Tian Jingyi, Cai Huaqing
    1999, 10(6):  673-675. 
    Asbtract ( 1765 )   PDF (168KB) ( 450 )  
    The study indicated that three soilmass structural patterns found in Leling jijithus producing area were in the following sequence in accordance with their quality:clayey>muddy-loam>sandy-loam.This sequence was just positively correlated with soil nutrient contents and consistent to the quality sequence of jijithus:high,moderate,and low-quality.
    Mechanism of nutrient preservation and supply by soil and its regulation Ⅲ N preservation and supply by brown earth type vegetable garden soil
    Chen Lijun, Zhou Likai, Zhang Xiulan
    1999, 10(6):  676-678. 
    Asbtract ( 1348 )   PDF (737KB) ( 436 )  
    Determination of N preservation and supply performances of 15 pairs of fertile and infertile brown earth type vegetable garden soils sampled from northern, central and southern Liaoning province show that in most soil samples tested, fertile soils and their various particle sizes of microaggregates had a larger amount of total N and adsorbed and desorbed NH4+, but a smaller desorption rate than infertile soils and their corresponding particle sizes of microaggregates. There are significant different between total N, adsorbed and desorbed NH4+ of fertile and infertile soils and their microaggragate of <10μm. The amount of adsorbed and desorbed N decreased with the increment of microaggregates particle sizes in both fertile and infertile soils, but the desorption rate was reversed. NH4+ adsorption had no significant linear relationship with soil nutrients and enzyme activities,but NH4+ desorption of fertile soils and their various particle sizes of microaggregates had significant linear positive relationships with soil organic matter and its binding status, total Ncontent, urease and phosphatase activities, NH4+ desorption of infertile soils and their corresponding particle sizes of microaggregates had no significant linear positive relationships with all nutrients contents and enzyme activities.
    Theory and practice of calibration and validation of crop simulation model
    Qiu Jianjun, Xiao Yingnan, Xin Dehui, Hu Xining
    1999, 10(6):  679-682. 
    Asbtract ( 1866 )   PDF (1486KB) ( 480 )  
    Taking GOSSYM model as an example,the theory and methodology for calibration andvalidation of crop growth simulation model were expounded in this paper.The variety and soil parameters of the model used in cotton planting area of Xinjiang were calibrated,some modules of the model were modified, and the result of calibration was also validated. The results show that at two experimental sites, the observational values of soil moisture in 20~40 and 60~80 cm layers in growing season were better identical to those simulated by the model with calibrated soil parameter. The coefficients of simulated and experimental values of six biological indexes of Xi-5 (an early maturity cotton variety) in its growth and development period were all above 0.9,and the relative errors of the simulating yields of three treatments under different cultivation conditions were averaged by 7.5%.
    Interactive effect of genotype and environment on heterosis of panicle traits of rice (Oryza sativa)
    Liang Kangjing
    1999, 10(6):  683-688. 
    Asbtract ( 1696 )   PDF (296KB) ( 389 )  
    Based on two years experiment data, and using the models of genetic effects and genotype×environment (GE) interaction for additive dominant additive×additive epistasis, this paper analysed the heterosis of panicle traits of rice (Oryza sativa). The results indicated that the heterosis of seven panicle traits was affected by both genetic and environmental factors. Asignificantly positive heterosis over mid parents based on population mean (HMP) was observed in spikelet number of main panicle (SMP), main panicle length (MPL), total length of primary branches (TLPB), total length of secondary branches (TLSB) and spikelet density (SD), while the reverse was true in the case of the numbers of primary branches (PB) and secondary branches (SB). The predicated results of GEinteraction showed that its positive effect was observed in SMP, MPLand TLPB, negative effect was found in PBand SB, while different directional effect was detected in SDand TLSB. Aheavy panicle type structure could be easily obtained from hybrid progenies by using IR66158-37(P1), IR65600-85(P2), Minhui 63(P4) and R669(P6) as crossing parents, which could be used for the breeding of super high yielding varieties of rice.
    Effect of topsoil drought and root signals on yield formation of spring wheat
    Guo Anhong, Li Fengmin, Li Zhaoxiang, Pang Binshuang, Shan Lun
    1999, 10(6):  689-695. 
    Asbtract ( 1405 )   PDF (354KB) ( 371 )  
    In this study,horizontally segmented soil columns were sampled to simulate field situation,and to investigate the behavior of non hydraulic root signals and its effect on spring wheat yield under definite water deficiency.Three spring wheat cultivars (A,B,C) were tested in the experiment with three watering treatments:well watered (CT),limited watered from upper soil layer (DIu) and limited watered from deeper soil layer (DId).During 17~28 days after emergence (DAE),the stomatal conductance and transpiration rate in treatments DIu and DId were reduced significantly without any apparent change in leaf water potential,indicating the typical non hydraulic root signals,and the leaf water potentials differed significantly with treatment CTover time. Among the three cultivars,the upper root system of cultivar Bhad a higher SRW (specific root weight) at 34 and 54 DAE and a higher biomass at 54 DAEthan cultivars Aand C,which is favorable to cultivar Bfor its high yield. Comparing with cultivars Aand B,cultivar Chad a higher proportion of total root biomass and total root length in upper root layer in treatment DIu at 34 and 54 DAE,and a relatively smaller proportion in middle root layer. In treatment DId,the allocation pattern of root systems of three cultivars was contrary to that in treatment DIu. It is suggested that cultivar Cwas more sensitive to topsoil moisture and more plastic on root allocation than cultivars Aand B, which also reflected its higher sensitivity to root signals. Cultivars A and B had a relatively poor plasticity of roots,but had a significantly higher grain yield than cultivar C.
    Structural comparison of Glycine soja in different ecological environments
    Wang Guiqin, Zhang Changzhong, Lu Jingmei, Li Jiandong
    1999, 10(6):  696-698. 
    Asbtract ( 1461 )   PDF (203KB) ( 382 )  
    Observations on two ecotypes of Glycine soja under scanning electronic microscope showed that the ecotype growing in saline ecological environment had salt glands on the surface of its stems and leaves, which distributed at intercellular layer,in the shape of ball and with a handle at the base. Younger salt glands secreted salt ions through their secretary pores, and mature ones did it by breaking themselves. The ecotype growing on black soil did not have any salt glands on the surface of its stems and leaves, and the surface was smooth. Therefore, the ecotypes of G.soja growing in different ecological environments displayed an obvious difference in their microstructure.
    Diffusion and migration dynamics of Aphis gossypii on Hibiscus syriacus plants
    Zou Yunding, Zhou Xiazhi, Li Guiting, Liu Tongwen
    1999, 10(6):  699-702. 
    Asbtract ( 1367 )   PDF (450KB) ( 428 )  
    The fluctuation dynamics, diffusion and migration of Aphis gossypii population on Hibiscus syriacus and cotton plants were studied. The distribution of Aphis gossypii on Hibiscus syriacus plants from April 20 to May 6 was aggregate with the bigger density in the eastward, and most in No. 4 and No. 10 plants. After May 6, the distribution changed due to diffusion. The number of Chrysopa septem punctata was related to that of Aphis gossypii, while the relationship between the total number of all the natural enemies and the number of Aphis gossypii was extremely significant. The influence order of natural enemies on Aphis gossypii was Propylaca japonica > Tromobididiidae > Chrysopa septem punctata. The growth model for Aphis gossypii population on Hibiscus syriacus from April 18 to May 16 was linear. The relative humidity of the day before was significantly related to the winged adult rate. The rate of winged adult aphids in cotton field was extremely significantly related to that on Hibiscus syriacus two days before.
    Ecological effects of six diseases and insects on larch crown
    Wang Zhiming, Liu Guorong, Wang Yongmin, Jing Tianzhong, Ren Wanjun, Wang Jianguo
    1999, 10(6):  703-706. 
    Asbtract ( 1452 )   PDF (508KB) ( 628 )  
    The fungi of Mycosphaerella larici-leptolepis,Botryosphaeria laricina,Triphragmiopses laricimum and insects of Coleophora dahurica,Adelges laricis,Cinara laricis are common pests on larch (Larix olgensis). Each species possesses different ecological niche on larch crown. The effects of different insects (or developmental phases) and diseases on larch crown showed the phenomena of alternate emergence over time,inter evasion and selecting different ecological environments.The life table of 6 pests showed that the insect pests were major pests of the larch crown from late May to early July.After late July when fungi diseases invaded the needles and shoots,the larch was injured seriously.When3 insect pests attached larch only,the Kx value in life table was 0.016~0.0197. While the diseases affected,Kx was up to 0.124,reaching0.26 on September 7. The fungal diseases seriously defoliated larch trees in August,which could affect continuously the growth of larch for 3 years,and most seriously in second year. C.dahurica defoliated trees in May.
    Relationships among spatial patterns of Chrysopa sinica,Propylaea japonica and Helicoverpa armigera
    Lu Yongyue, Yin Chudao
    1999, 10(6):  707-709. 
    Asbtract ( 1495 )   PDF (178KB) ( 450 )  
    Relationships among the spatial distribution patterms of Helicoverpa armigera, and its matural enemies Propylaea japonica and Chrysopa sinica were studied through field investigation. The result showed that the correlation coefficients of quantity in vertical distribution between H. armigera and P. japonica, and H. armigera and C. sinica were 0.5696 and 0.8620 in June,0.8300 and 0.9282 in July,and 0.9083 and 0.8201 in August,with all significant differences except for P. japonica in June. The correlation coefficients of spreading coefficient and Kuno index were 0.8211 and 0.7791 between H. armigera and P. japonica in vertical patterns,and 0.7925 and 0.5228 between H. armigera and C. sinica in horizontal patterns.
    Effect of temperature on development,survival and reproduction of Liriomyza sativae
    Chen Yan, Zhao Jingwei, Fan Qinghai
    1999, 10(6):  710-712. 
    Asbtract ( 1599 )   PDF (445KB) ( 465 )  
    This paper studied the development,survival and reproduction of vegetable leafminer (Liriomyza sativae) at eight constant temperatures (12,15,20,25,27.5,30,32.5 and 35℃) with 70%±5% R.H. and 14L◊10Dphotoperiod.The initiative development temperature and the available accumulation temperature were estimated to be 8.77℃ and 295.69 day degrees,respectively.The regression equations of development rate with temperature at various immature stages were given.The survival rates at various immature stages were higher at 20~27.5℃.Most of the death occurred at pupal stage,and no pupae could emerge at 35℃.The longevity of the adult decreased with increasing temperature,and the population growth index reached a peak at 27.5℃.
    A survey on the incidental catches of small cetaceans in coastal waters of China
    Yang Guang, Zhou Kaiya, Xu Xinrong, Stephen Leatherwood
    1999, 10(6):  713-716. 
    Asbtract ( 1705 )   PDF (415KB) ( 571 )  
    This paper provided the results of the survey on the incidental catches of small cetaceans in coastal waters of China, which was conducted in1994~1995. Finless porpoise (Neophocaena phocaenoides) was captured most frequently in the Chinese coastal fisheries, while other small cetaceans, including long beaked common dolphin (Delphinus capensis), bottlenose dolphin (Tursiops truncatus), pantropical spotted dolphin (Stenella attenuata), and false killer whale (Pseudorca crassidens), were caught incidentally. In1994, the annual incidental catches of small cetaceans in coastal waters of Zhejiang, Fujian, Guangdong, Hainan and Guangxi were about 3045±2120 individuals, whereas those of finless porpoise were about 2132±1484. The gears for incidental catches were predominantly trawl nets, gillnets, and stow nets. No direct catches of small cetaceans existed in China. The incidentally captured small cetaceans did not occupy an important place in the daily life of people in coastal China, and they were discarded in the sea or sold at a very low price in fish markets. The exact impact of incidental catches on small cetaceans in Chinese waters was not clear at present, but it has probably caused the decline of their populations.
    Effect of rodenticide (chlorophacinone) on structure and succession of small mammal community in agroecosystem
    Zong Hao, Jiang Guangzao
    1999, 10(6):  717-720. 
    Asbtract ( 1588 )   PDF (217KB) ( 317 )  
    The result shows that rodenticide significantly affected the structure of the mammal community, and the effect differed with rat killing time and frequency.When rat killing in autumn,the small mammal density declined year by year,and reached a low level after three years, with a decrease of community diversity and a weak recovery. When rat killing in spring,the density could be kept at a low level,however,the diversity was higher than other treatments,with a strongcapacity of restoring the biodiversity. Increasing the frequency of rodenticide application intensified the effect on decreasing the density of small mammals. Therefore, chemical rat controlling obviously decreased the density of small mammals and the diversity of the community, and promoted the community succession with more prominent dominant species, monotonous community composition and unstable structure direction.
    Ecological distribution of arbuscular mycorrhizal fungi in saline alkaline soils of China
    Liu Runjin, Liu Pengqi, Xu Kun, Lu Zhifan
    1999, 10(6):  721-724. 
    Asbtract ( 1941 )   PDF (562KB) ( 573 )  
    The compositions of species and genera of arbuscular mycorrhizal (AM) fungi in saline-alkaline soils of China and their ecological distributions were studied in this paper. They were correlated to soil type, alkalinity and organic matter content. The species number of Glomus genus was the highest in sandy, loam and clay soils, followed by Acaulospora genus. Glomus mosseae was the dominant species in these soils. The frequency of G. mosseae was increased with increasing alkalinity. In a certain extent, the higher the content of soil organic matter, the more the species were isolated. The components of the genus and species of AM fungi were also influenced by host plants, and the numbers of them in the rhizospheric soils of leguminous plants were greater than those in others.
    Fertility significance of microbial biomass in red soil ryegrass system
    Yao Huaiying, He Zhenli, Chen Guochao, Huang Changyong
    1999, 10(6):  725-728. 
    Asbtract ( 1585 )   PDF (555KB) ( 742 )  
    The study on the inherent relations of microbial biomass in red soil with soil nutrient cycling and ryegrass growth shows that the microbial biomass was not only significantly correlated with soil organic C, total N and available N, but also highly correlated with dry matter yield and Nuptake of plants,indicating that soil microbial biomass could be used as an important indicator for soil fertility and plant production. The turnover period of microbial biomass Nin red soil was relatively short, and the annual flux of Nthrough microbes was as 1.5 times or more as microbial biomass N.
    Effect of environmental temperature on formation of cellulase and xylanase in Thricholomataceae L1
    Cai Jingmin, Wu Ke, Zhang Jie, Liu Yunfeng, Pan Renrui, Ding Zuolong
    1999, 10(6):  729-731. 
    Asbtract ( 1422 )   PDF (170KB) ( 464 )  
    Higher environmental temperature is beneficial to the growth of Tricholomataceae L1 and its protein synthesis. When temperature is 38℃, the specific activity of cellulase is the highest, reaching 23.4Iu·mg-1 protein. After cultivated for 93 hours at this temperature, its cellulase activity is 33Iu·g-1 dry medium. The optimal temperature for the formation of xylanase is 32℃. Under this temperatrue, the specific activity of xylanase is 92Iu·mg-1 protein, and after cultivated for 67 hours, it is 126Iu·g-1 dry medium. It is suggested that environmental temperature has a regulation effect on the formation of intracellular enzyme of Tricholomataceae L1.
    Fermentation conditions of β-glucosidase production from Asp niger
    Li Ping, Wan Xiaochun, Tao Wenyi, Ding Xiaolin
    1999, 10(6):  732-734. 
    Asbtract ( 1695 )   PDF (518KB) ( 516 )  
    Through multinomial regression, the effects of different concentrations of carbon source, nitrogen source and inorganic salts on β glucosidase production were studied. The optimum components of mediums consisted of bran 4.9%, (NH4)2SO4 0.4%, KH2PO4 0.29%, CaCl2 0.05%, MgSO4·7H2O0.04%, FeSO4·7H2O 5mg·L-1, ZnCl 21.4mg·L-1, and sodium oleate 0.2%. The fermentation conditions (including temperature, time, pH, aeration, and inoculation rate and pattern) were also optimized. Under the optimized conditions, the activity of β-glucosidase produced from Asp. niger was increased from 17U·ml-1 to 21.3U·ml-1.
    Population dynamics of endophytic bacteria in symptom free rice plants
    Liu Yunxia, Zhang Qingwen, Zhuo Mingzang
    1999, 10(6):  735-738. 
    Asbtract ( 1618 )   PDF (174KB) ( 388 )  
    The population dynamics of endophytic bacteria in different tissues of rice plants (cultivars Shennong 319 and Zhongbai 4) was studied during their development stages. The results showed that the population of endophytic bacteria was the largest in roots, followed by in leaves and stems. And the population size was the largest at tillering stage, and gradually decreased with the senescence of tissues. Among the four isolated bacterial species, Bacillus megaterium was the dominant endophytic bacterium in the two rice cultivars. The studies on the species of endophytic bacteria and their population dynamics in tissues with the growth of rice plants could provide effective carrier bacteria to select the insect killing bacteria in genetic improvement engineering for biological control of rice insects.
    Effect of La on Ca content in tobacco callus and oilseed rape seedling root
    Zhang Jiarong, Gu Yuehua, Luo Jianping, Zhao Guiwen
    1999, 10(6):  739-742. 
    Asbtract ( 1565 )   PDF (993KB) ( 368 )  
    The Ca contents in tobacco callus and in its protoplasts were lower in La contained (0.01~0.10mmol·L-1) MSmedium than in the control (without La addition). As the culture time increased from 1 day to 30 days, the Ca contents declined rapidly. At low La concentration (0.01~0.05mmol·L-1), the Ca content in cell wall was higher than that of the control, and increased with increasing La concentration; while at high La concentration (0.10mmol·L-1), it decreased. Compared with Ce, La had a weaker effect on Ca exudation. After oilseed rape seeds were soaked with different concentrations of La(NO3)3 solution, the dynamics of Ca content in their seedling roots and protoplasts were the same as above mentioned. La made the tobacco callus quickly browned, and the increment of fresh weight was lower than that of the control.
    Ecological differentiation and variety degeneration of maize under heavy metal contamination
    Zhang Taiping, Duan Changqun, Hu Bin, Wang Huanxiao, Peng Shaolin
    1999, 10(6):  743-747. 
    Asbtract ( 1629 )   PDF (1266KB) ( 556 )  
    Different populations of maize (Zea mays L.) having been exposed to heavy metal contamination in different durations were replanted on unpolluted soil,and the difference of their quantitative characters such as average relative growth rate,flowering percentage at different time, plant weight, plant height,ears weight, 50 seeds weight and lengths of effective and noneffective ears was investigated.The results show that the populations exposed to heavy metal contamination in a longer duration had a lower relative growth rate,shorter lifecycle,shorter height and lower productivity,indicating that the adaptation of maize to heavy metal contamination led to its ecological differentiation and variety degeneration. The tolerance cost of maize in adapting heavy metal contamination was also discussed.
    Allelopathy of Ageratum conyzoides Ⅲ Allelopathic effects of volatile oil from Ageratum on plants under different nutrient levels
    Xu Tao, Kong Chuihua, Hu Fei
    1999, 10(6):  748-750. 
    Asbtract ( 2691 )   PDF (401KB) ( 612 )  
    Allelopathic effects of the volatile oils from Ageratum conyzoides on radish, mungbean and ryegrass under different nutrient levels of Hoagland solution were studied. The results showed that with the decrease of nutrient level, the allelopathic effects of the volatile oil increased significantly. Under the impact of the volatile oil, the contents of chlorophyll, soluble proteins and the activity of PODin three plant species were decreased, while the relative plasma membrane permeability and the content of MDA increased. The chemical components and relative contents of the volatile oil from Ageratum conyzoides were analyzed by GC/MS. Sixteen compounds were identified, and precoceneⅡ, precoceneⅠand caryophyllene are the main components, with relative amount of 36.85%, 26.41% and 19.84%, respectively.
    Ecosystem health and sustainable development for human
    Zeng Dehui, Jiang Fengqi, Fan Zhiping, Du Xiaojun
    1999, 10(6):  751-756. 
    Asbtract ( 2475 )   PDF (651KB) ( 1354 )  
    Ecosystem health is a new integrative science, which deals with implementing strategies in natural resources and environmental management. Authors introduce the origination and connotation of the concept of ecosystem health and main research contents in ecosystem health; expound the relationships between ecosystem health and sustainable development for human. The authors also introduce some famous practices on ecosystem health around world, and provide suggestions that it should be urgent to address the research in the field of ecosystem health in China. The emerging discipline of ecosystem health could provide new hopes for the healthy and sustainable development of human society.
    Net primary productivity of terrestrial vegetation—a review on relatedrsearches
    Sun Rui, Zhu Qijiang
    1999, 10(6):  757-760. 
    Asbtract ( 2124 )   PDF (468KB) ( 725 )  
    Net primary production (NPP) of terrestrial wegetation is significant in global change study.Different NPP models were developed to simulate the distribution of global and regional NPPin the last two decades, of wbich, climate relative models,process models and energy use efficiency models were the main ones. Each kind of these NPPmodels had its advantages and disadvantages.Climate relative models were attractive for their applicability to climate change problems, but little insight into nonequlibrium phenomena was provided. Process models emphasized on the physiological and ecological processes of plant growth, but they were too complicated to get some parameters.Energy use efficiency models were attractive because the vegetation index data from satellite remotely sensed observations could be directly used to estimate the fraction of absorbed photosynthetically active radiation.The NPPresearch status and the application of remote sensing in NPPresearch in China were also reviewed in this paper.
    Flood damage and controlling strategies at Hun Tai basin
    Pei Tiefan, Fan Shixiang, Li Xiaoyan, Wu Jiabing, Xu Yi
    1999, 10(6):  761-765. 
    Asbtract ( 1529 )   PDF (258KB) ( 418 )  
    Hunhe, Taizihe rivers originating from the east mountain areas of Liaoning Province are the biggest tributaries of the left bank of Liaohe River. From the initial stage of New China to the early 1990s, the frequency of flood damage had decreased, but recently the disasters have upgraded and changed from trunk stream to tributary basins. In July 1995, Dongzhouhe, a tributary of Hunhe River, suffered from a heaviest flood since establishing the document of floods in Hunhe basin. Meanwhile, a peak discharge, almost beyond double defending ability, occurred at Dadongshanpu Station of Beishahe River, a tributary of Taizihe River. Besides the continued heavy rainstorm, no controllable water conservancy projects and ecological damages caused by quickly decreasing forest cover and water and soil loss are the two main causes of flood damage. In addition, the low flood protection standard is also one of causes. According to the above analyses, some strategies of synthetic controlling for flood damages were put forward: 1) Establishing the system of ecological engineering to defend floods and reduce disasters; 2)Setting up storage and detention areas; 3) Establishing flood controlling information system; 4) Improving the accuracy of media short period and short period rainstorm forecast and flood forecast; 5) Insurance of flood protection.
    Existing forms of heavy metals and their toxicity in foods
    Yang Jurong, Zha Yan
    1999, 10(6):  766-770. 
    Asbtract ( 2265 )   PDF (872KB) ( 1001 )  
    This paper briefly introduced the research advance about the forms of heavy metals and their relationships with toxicity in some foods. The characteristics of chemical forms of heavy metals in foods, the existing forms of heavy metals in different types of foods, and the relationships between the forms of heavy metals in foods and their bioavailability and toxicity were summarized. Some problems urgent to be resolved in this field were put forward.