Table of Content

25 July 1994, Volume 5 Issue 3

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Articles

Death causes from withering of Larix olgensis in Changbai Mountain area

Zhong Zhaokang, Yuan Zhiwen, Yang Jinkuan, Dai Hongcai, Zhao Min

1994, 5(3):  226-231. 

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In this paper, the death causes from withering of Larix olgensis in Changbai Mountain area are investigated interdisciplinarily. The results show that the death of L. olgensis is not directly related to forest disease and insect pests, and the formation of high moor on forestland can lead to the lack of oxygen in root zone and the hindering of root respiration, which is a direct cause of L. olgensis death.

Application of Markov process in structural dynamic forecasting of forest resources with tree species structure in Nanping region of Fujian Province as an example

Chen Jianzhong, Zhou Shiyong, Xu Fuyu

1994, 5(3):  232-236. 

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Based on the theory of Markov process,and the data obtained from fixed plots for continuously surveying forest resources, the tree species structure in Nanping region is forecasted and adjusted. The results show that the ratio of conifers to broad-leaved trees will be seriously imbalance and the occupied ratios of Phyllostachys pubescens and economic trees will be decreased gradually. The tree species structure will be lied in a stable state, e. g., Cunninghamia lanceolata occupies by 28.05%, Pinus massoniana by 16.63%, broad-leaved trees by 19.01%, Phyllostachys pubescens by 5.43%, economic trees by 2.26%, and others by 28.71%. After adjustment, they occuy by 18.72, 13.24, 26.98, 10.84, 5.45 and 24.77% respectively.

Population ecology or Acanthopqnax senticosus Ⅱ. Population statistics

Zhu Ning, Zang Runguo

1994, 5(3):  237-240. 

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The life tables of Acan thopanax senticosus population under three natural secondary forests are compiled with its ramet as statistic unit,and the population dynamics are analysed. The results show that the population has two peaks of mortality, and its death intensity has signifcant difference in different forest communities. The total killing power is different, too. All these are related to the habitats of communities. The survival curves of the population approximate to the Deevey Ⅲ.

Influence of repeatedly planting soil on Cunninghamia lonceolata sapling growth

Zhang Jiawu, Deng Shijian, Liao Liping, Gao Hong

1994, 5(3):  241-244. 

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Pot experiment results of Cunninghamia lanceolata saplings on three types of repeatedly planting soils of Huitong forest area show that repeatedly planting soil is not suitable for sapling growth, the height growth is decreased by 37-40%, base diameter by 19-28 %, canopy size by 21-29, and total biomass by 45-50%. Repeatedly planting of Cunninghamia lanceolata also induces the decrease of soil fertility: humus content by 17-28%, available nutrients by 23-28%, and the number of soil microbes and their activity are declined significantly. It is suggested that the management system of repeatedly planting pure Cunninghamia lanceolata stand should be abandoned.

Fuzzy cluster analysis on climatic conditions of world's major peach-growing areas and their relations to the ecotypes of peach genetic resources

Li Zailong, Luo Weihong, Pang Zhenchao

1994, 5(3):  245-250. 

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Key climatic factors affecting peach-growth and its distribution, i. e., overwintering temperature, percentage of sunshine hour and rainfall during growing seasons, are selected to make fuzzy cluster analysis and to classify the regions of world's peach-growing areas. The results show that based on the average air temperature from December to February, world's major peach -growing areas can be classified into three types of regions characterized with cold(<3.0℃), temperate(3.0-10℃) and mild(>10℃) winter. And, based on the percentage of sunshine hour and rainfall from April to October, they are classified into three regions characterized with sufficient sunshine and dry (63-92%,<400mm), more sufficient sunshine and semi-humid (55-71%, 432-1001mm) and insufficient sunshine and humid(<55 %,717-1727mm). Most of world's peach yields are concentrated in the regions with sufficient sunshine and less rainfall during growing season and with not very cold winter. Within a range of suitable temperature, peach cultivars can be introduced from one region to another.

Shelterbelt porosity model and its application

Jiang Fengqi, Zhou Xinhua, Fu Menghua, Zhu Jiaojun, Lin Heming

1994, 5(3):  251-255. 

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Based on the measurement of porosity of typical poplar shelterbelts in the west part of Northeast China with digitized photographic silhouettes. dominant. factor model(DFM) and mechanism model(MM) of shelterbelt porosity are established. The DFMis made by dominant factors relating to shelterbelt structure with successive regression analysis, and the MM is constricted by tree species and their depositions with model theory. Mean-while. the application of DFM and MM in regulating shelterbelt structure are also given in this paper.

Residual effect of phosphorus fertilizer and phosphorus recycling in a farming system Ⅳ.A simple phosphorus recycling model in a farming system and its test

Chen Shi, Yin Xiuyan, Zhang Lu, Shen Shanmin

1994, 5(3):  256-262. 

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Asimple phosphorus recycling model is established and validated based on a six years field experiment conducted on a calsic cinnamon soil in West Liaoning. The long-term simulated prediction of four ways of applying phosphorus fertilizer shows that the applying P every six years with high rate and with pig manure recycled each year is better than other ways of P fertilization from the view of higher crop yield and soil available Plevel and greater recovery rate of applied P.

Behavioural ecology of Azure-winged magpie(Cpanopica cyana) during its breeding period

Shang Yuchang, Li Liubin, Wang Fei, Wang Hao

1994, 5(3):  263-268. 

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The breeding period of Azure-winged magpie has a delay with increasing latitude from south to north, and the position of its nests are higher from the ground and more cryptic with increasing population density. This kind of strong adaptive ability to environment make them survival and reproduction well in city and its suburbs. Azure-winged magpie in Beijing district begins to nest in the middle or late April, and reaches the top of laying-eggs period in the late May. Azure-winged magpie always turns over its eggs during incubation. When exchanging its eggs with quail's ones, it's found that Azure-winged magpie is much sensitive to egg's number than its size and color. The incubation period is 15-17 days, and the fledgelings leave their nest in 18-20 days after hatching. The successful rate of breeding in the campus of Peking University is about 69.05%. Adevelopmental ethogram of Azure-winged magpie is set up there. Their nests are dense and form a collective breeding territory. They are cooperative efforts in defence of a breeding territory.

Changes of natural habitats on Zhouskan Island and their effects on species extinction of mammals

Li Yiming, Li Dianmo

1994, 5(3):  269-275. 

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Owing to the anthropogenic disturbance, the natural habitats on Zhoushan Island, whose area occupies 56.3% of the total, are disappeared. They are fragmented into many fragments and their quality is greatly changed. Just for these, and over-hunting, 5 species of mammals are extincted and 3 species of them are going to extinction, the extinction rate being higher than that on the continent closed by. Population growth is the main cause of the disappearance. fragmentation and quality descending of natural habitats and the extinction of mammal species. Some countermeasures and their principles for conserving natural habitats and species diversity are discussed in this paper.

Relationship between chemical compositions of "8455" wheat plant and population dynamics of Schizaphis graminum and Macrosiphum avenae

Zou Yunding, Meng Qinglei, Ma Fei, Huang Shixiang, Hu Lijuan

1994, 5(3):  276-280. 

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The influence of chemical compositions of "8455" wheat plant under two fertilization levels on population dynamics of Schizaphis graminum and Macrosiphum avenae is studied. The results show that soluble carbohydrates, potassium and water contents of wheat plant significantly affect the population dynamics of Schizaphis gramninum and cystine content is the main factor affecting the population dynamics of Maocrosiphum avenae.

Life table of Tryporyza incertulas population

Zhang Xuanda, Gu Dexiang, Zhou Hanhui

1994, 5(3):  281-286. 

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From 1984 to 1988, nine generations of paddy borer, Tryporyza incertulas, were observed at Sihui county, Guangdong Province and the survival curves of each generations were plotted based on the life table data. The hashest mortality occured at the boring stage of young instar larvae (65.77-80.26%), and the type of survival curves appeared to be Slobodking IV. The k-values in all life tables show that k₉ is highest and k₅ is the next. Key factor analysis were conducted with Varley's diagram and Podoler's regression methods respectively. The first key factor was the mortality for transmigration in old instar larvae stage and the second was the invasion mortality in young instar larvae stage.

Predicting models of population dynamics or cotton aphid

Wu Kongming, Zhao Bingyi

1994, 5(3):  287-291. 

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Population dynamics of cotton aphid in cotton fields of Henan Province in 1980-1989 are analyzed in this paper. The results show that the damage period of cotton aphid is at the seedling and flowering-bolting stages of cotton. With consideration of environmental factors (temperature, relative humidity and rainfall) and different damage stages, two fuzzy predicting models are established and good predicting result are obtained.

Transposon Tn5 used as an identifiable ecological marker of R. fredii stains: Horizontal transfer frequency of transponson Tn5 and its influence on the movement of R. fredii Tn5 mutant

Lin Jishang, Cui Mingxue, Jin Shuying, Li Mingqi, Li Ning, Zhao Wei

1994, 5(3):  292-298. 

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Atransposon Tn5 insertion mutant ON-2 of Rhizobium, fredii wild strain QB1130 was used in ecological study to evaluate the probability of horrizontal transfer of transposon Tn5 in natural environments and its influence on the movement of mutants. The results show that the horrizontal transfer frenquency of Tn5 is very low in natural moist soil. The Km^tphenotype of the mutant associated with Tn5 insertion is shown to be stable after growth for over 40 generations on nonselective media. No significant difference(P=0.01) between the movements of the mutant and its corresponding wild type was found, which implies that transponson Tn5 does not influence the movement of Tn5 mutant. The study suggests that Tn5 can be selected as a stable ecological marker in monitoring R. fredii genetic engineering strains used in the field.

Infectiveness of Frankia strains from Hippophae rhamnoides

Zhang Chenggang, Zhang Zhongze, Li Weiguang, Wang Yuying, Su Fengyan

1994, 5(3):  299-302. 

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Three Frankia strains (Hr8,Hr16 and Hr32) from Hippophae rhamnoides are tested for inoculation in soils with native Frankia species. Hr16 has a compensational effect with native species. The inoculation efficiency of Frankia is influenced by various factors. Higher efficiency is obtained while Frankia is inoculated in soils within5cm in depth. The strains are cultured for 8 weeks, seedlings for 4 weeks and inoculation amount is 0.05 ml PCV.

Vicia faba used as a bioindicator for monitoring atmospheric SO₂ pollution

Chen Xiaoyong, Song Yongchang

1994, 5(3):  303-308. 

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Fumigation and exposure experiments show that for monitoring atmospheric SO₂, pollution. visible injured symptoms of Viola faba leaf is not a profitable indicator, but its superoxide dismutase(SOD) activity, ascorbic acid(ASA) content, amino acid(AA) content, peroxidase(POD) activity and chlorophyll content are good indicators, among which, SOD activity is the best one. Using these five indicators to make an integral assessment will be better than using each of them.

Interaction between Eichhornia crassipes and its rhizospheric bacteria

Wang Min, Zheng Shizhang

1994, 5(3):  309-313. 

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The relationship between Eichhornia crassipes and its rhizospheric bacteria is markedly influenced by nutritional condition. The root exudates of the plant growing on sucrose containing medium have little effect on the dynamics of bacteria growth, but on phenol containing and inorganic media, the root exudates can respectively promote two- and three- fold growth of bacteria. Under phenolic condition, there exists a stronger rhizospheric effect: the metabolites of rhizospheric bacteria can promote the polyphenoloxidase activity of Eichhornia crassipes, but inhibit its peroxidase activity and decrease its phenol content. Eichhornia crassipes inoculated with bacteria has a higher activity of polyphenoloxidase and peroxidase and a higher content of phenol.

A preliminary analysis on the euclosed experimental results of red tide formation Ⅱ.Phytoplanktou succession and dinoflagellate red tide

Lin Yu, Zhuang Dongfa, Chen Xiaolin, Tang Senming

1994, 5(3):  314-318. 

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The relationship between phytoplankton succession and dinoflagellate red tide is discussed in this paper. Aseries of marine enclosed experiments in different seasons and years show that in an ecosystem of relatively stable water body enriched with nutrients, a dinoflagellate red tide always appeares following the diatom bloom or its red tide in phytoplankton succession. The abnormal increase of vitamin B₁₂ may promote the succession processes. The succession in stable water column could be interfered by stirring. Under this condition, the diatom bloom would develop continuously. block the formation of dinoflagellate dominance and prevent its red tide formation. The experimental results have practical meaning as they may be used to predict possible dinoflagellate red tide occurrence in enclosed or semi-enclosed waters.

Structure of zooplankton community in Donghu Lake of Wuhan

Yang Yufeng, Huang Xiangfei

1994, 5(3):  319-324. 

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The structure of zooplankton community in Donghu Lake of Wuhan was studied in 1991. The number of zooplankton at stations Ⅰ. Ⅱ and Ⅲ is respectively 122782, 70415 and 18184 individuals. L^-1, being increased with increasing eutrophication of water body, and the biomass is 8.639, 5.872 and 2.082 mg·L^-1 respectively. The frequency of large-sized crustacean (>1mm) is respectively 0.15, 0.30 and 0.41, and its body length is shortened with the increase of fish yield. Ecological factors affecting the structure of zooplankton community are discussed.

Ecology of genetically engineered microorganisms and risk assessment for their planned release

Zhang Shangtong, Xu Chongren

1994, 5(3):  325-330. 

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The environmental applications of genetically engineered microorganisms(GEMs) may cause many safety problems, It's necessary to assess the possible impacts of their planned release on ecosystems, with emphasis on the potential of horizontal transfer of artificially introduced genes between GEMs and indigenous microflora. and other ecologically important parameters like survival, dissemination and competition. It's also important to search for more valid methods of detection and to improve the strategy of risk assessment. The study is helpful for development of molecular ecology and application of biotechnology.

Mathematical methods in niche theory study

Huang Yingzi

1994, 5(3):  331-337. 

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Structural relationships among species and their individuals can be revealed from all aspects by measuring different niche parameters. Multivariate statistical method can provide appropriate models for analysing H-niche, and set-theoretic method will give more informations on the mechanisms of competition, coexistence and interaction among species in a community.