Table of Content

10 October 1991, Volume 10 Issue 05

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Seasonal Pattern of Photosynthesis and Nutrient Content of Korean Pine Seedlings Under Different Light Conditions

Li Junqing, Chai Yixin, Zhu Chunquan, Wang Yeju

1991, (5):  1-5. 

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Comparative experiments have been carried out to determine the height growth, photosynthesis, nutrient content and their seasonal courses for Korean pine seedlings under different light conditions. Shadings during both growing and non-growing seasons can affect the growth of Korean pine seedlings. Insufficient light illumination reduces their photosynthetic rate, nutrient uptake and normal physiological-metabolism activities. The growth retardation of virgin Korean pine seedlings under birch forest are proven to be resulted from the double effects of growing and non-growing seasons shadings. They disturb the photosynthesis and metatolism of Korean pine seedlings and lead to their growth retardation and poor regeneration.

Spatial Pattern of Ladybird Beetle on Chinese Cabbage and Its Sampling Techniques

Cai Xiaoming, Shang Yuchang, Yah Guiyun, Chen Jiding, Yan Junjie

1991, (5):  6-11. 

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The spatial pattern of ladybird beetle Coccinella septempunctata on Chinese cabbage follows a Poisson distribution. In data processing, Iwao's m-m model and its improvements are used. The fitness of Pearson-Ⅲ curve equation to the distribution of ladybird beetle population is tested and optimum sampling size and area for different population densities and relative pracisions are determined. It is concluded that when the population density of ladybird beetle is around 2.044 individuals per m² or 0.344 individuals per plant, its distribution is random.

Ecophysiological Effects of Paddy Field Under Different Soil-Water Regimes

Wu Zhiqiang, Lin Wenxiong, Liang Yiyuan

1991, (5):  12-15,45. 

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The hybrid rice "Weiyou 64" is used for the trial experiment with four soil-water treatments: paddy ridge cuiture with infiltration(PI), horizontal culture with continuous flooding(CF), alternate flooding(AF)and no flooding(NF). The results indicate that the leaf area index, net photosynthetic rate, bleeding sap, percentage of stored material translocation in stem and sheath, dry weight of shoot and yield in PI are much higher than those in CF, AF and NF. The ecophysiological effects of heat balance and soil mineral nutrients in PI are also investigated and described in detail in comparison with other three treatments.

Relationship Between Environmental Factors and Vegetative Distribution in the Edge of Big Youerdosi Marsh Basin

Zhang Li

1991, (5):  16-19,30. 

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In the Big Youerdosi Basin, dominant environmental factors affecting vegetative distribution are soil moisture, saIt and SO₄^- contents. Carex. and Stipa purpurea + Festuca sulcata formations are affected mainly by soil moisture content. The former is distributed only in places where moisture content is larger than 30%, and the latter is only distributed in where moisture content is less than 30%.The distribution of Leymus secalinus formation is dominated by soil SO₄^- content.

Benefits of Man-Made Catfish-Waterhyacinth-Snail Ecological Community

Wang Liuquan, Zhou Wanhua, Hu Xianjiang, Ding Fengqin

1991, (5):  20-22. 

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The advantages of this community can be summarized as:(1)superior in ccological stability.(2)growing well of catfish, water hyacinth and snail and(3)higher economic benefit than that of traditional fish culture in pond. The proper stocking size and density of catfish and snail and the proper cultivation and utilization of water hyacinth in the integrated community are discussed in the paper.

Preliminary Study on Litterfalls of Evergreen Broadleaved Forest in Qiping Forest Farm of Guangxi

Liang Hongwen, Li Jiejuan

1991, (5):  23-26,49. 

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The evergrean breadleaved forest in Qiping forest farm is a secondary south subtropical forest dominated by Schima supcrba. This paper focuses on the quantitative dynamics, composition and main chemical components of litterfalls:(1)the annual total amount of litterfalls is 8.385t.ha^-1, and the percentages of leaves, twigs and fruits-flowers are 51.75%, 26.11% and 22.14% respectiveIy.(2)the annual quantitative variation of litterfall is unobvious compared with seasonal variations, which is highest in March.(3)the ratio of total ash amount(290.34kg.ha^-1)to nitrogen amount(98.98kg穐a^-1)is 2.93:1, indicating the litterfalls of this forest belong to N-rich type.(4)the total amount of nine mineral elements in litterfalls is 128.5Sky.ha^-1, from maximum to minimum, their sequence is K>Ca>Mg>S>Mn>P>Fe>Zn>Cu.

Quality Control in Analysis of Soil Organic Pollutants in West Shenyang

Yu Dianchen, Liu Hailing, Zhang Lishan, Yao Jiabiao, Ho Donghui, Zhu Yan

1991, (5):  27-30. 

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In the analysis of soil organic pollutants.in west Shenyang, an ordinary compound, α-chloronaphthalene, is used to control analyzing process.There is a close relativity between recoveries of α-chloronaphthalene and other standard compounds. The average recovery rate of α-chloronaphthalene(R)is 85.6%, standard deviation(S)is 9.2 and relative standard deviation is 10.8%. Priority organic pollutants in the soil are anaiysed and R±3S is determined as the high and low limits to control analyzing quality. The results are satisfactory for practical use.

Effect of Site Conditions on Growth of Oriental Arborvitae Stand in Mount Qianfo of Jinan

You Zuoliang

1991, (5):  31-34. 

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Oriental arborvitae stand is the major community type in Mount Qianfo of Jinan. From mathematical analysis, it is found that major factors influencing its growth are stand density, soil water and soil depth. Their significance for four growth indices, i.e., height, dbh, basal diameter and standing stock are sequenced according to their values of standard regression coefficients. Optimal regression models of the four growth indices are founded using multiple step regression analysis. It quantitatively reveals the relationship between stand growth and environmental factors and provides theoretical and tcchnological guidance for the maintenance and development of forests.

Avian Species Diversity in Secondary Mountain Forests in Northeast China

Gao Wei, Xiang Guiquan, Feng Helin

1991, (5):  35-39,57. 

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Avian species diversities during their breeding seasons are investigated in secon dary mountain forests in Zuojia natural reserve, Songhua lake natural reserve, Tiangang natural reserve of Jilin province and Xianfeng forest farm of Heilongjiang province. The species composition, density and consuming biomass in the deseribed sites are similar, the diversities of foraging, foraging deight, foliage height and physioghomic coverage are also similar. It indicated the homogeneity of forest phase, avian composition and its diversity in secondary mountain forests is Northeast China. Because of the seasonal and annual variations of resources, birds can coexist by sharing natural resources.

Evolution and Ecological Adaptation of Social Behaviours in Insects

Shang Yuchang

1991, (5):  40-45. 

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Eusocial insects are characterized by four attributes:(1)a great number of adults living together in a group;(2)generations overlapping;(3)cooperation among adults in nestbuilding and brood care;(4)existing reproductive dominance and castes. There is a continuous series from entirely solitary to highly eusocial. This sequence provides clues to the evolutionary steps, by which, eusociality has evolved. Cooperative behaviours could originate from mutualism, kin selection and reciprocation. But, for the reasons of genetics, conflicts always exist in a colony, which must be suppressed to make the eusociality maintained.

Articles

Weed Allelopathy ahd Its Utilization in Biological Control of Weeds

Ma Yongqing, Liu Deli, Lovett J.V.

1991, (5):  46-49. 

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A brief introduction of w(?)d allelopathic researches toth in China and abroad is given, and common fiold woods with allelopathic potentials in China are listed.The utilization strategies of allelochemicals for biological control of woods and improving crop production are presented, such as management of crop sequences, utilization of allelopathic crop residues, breeding crops for weed controI and development of allelochemicals such as herbicide etc.

Quantitative Declination of Chinese Bee Colonies and Its Causes

Li Weisan

1991, (5):  50-53,61. 

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Breeding Chinese Bee has a long history in China. Owing to the change of its natural habitats, a long and intensive interruption of human activities, and the introduction and competition of western bee species(Italian Bee as the main), the distribution, quantity and density of Chinese Bee are becoming narrower and lower at great significance. This paper reviews the histery and present of Chinese Bee breeding, the causes for its quantitative declination and discusses the strategies for its preservation and development.

Measurement of CO₂ Concentration Under Film Covers of Late Sowing Wheat

Sun Benpu, Ji Jiahua, Li Xiuyun, Xu Qingxin, Zhang Baomin

1991, (5):  54-57. 

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Under film covers of wheat, the variatioa treads of CO₂ concentration are similar despite of different sowing time, old or new plastic films, or sunny or cloudy days. The diurnal course of CO₂ concentration can be divided into 3 stages: gradual rise, straight line drop and cyramic equilibrium. There will be lack of CO₂ in varying degrees when it is below the(ynamic equilibrium. Increasing CO₂ concentration under plastic films will greaty promote the photosynthesis and yield of late owing wheat.

Calculation Methods of Intrinsic Growth Rate(r_m)of Mammal Populations

Tang Yezhong, Kuang Rongping

1991, (5):  58-61. 

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This paper summarizes seven methods for determining and calculating the intrinsic growth rate(r_m)of animal populations, among which, Cole equation is emphathetically introduced, and its solution approaches, applied ranges and disadvantages are also discussed. The r_m of 17 mammal species are caiculated by Cole equation. The intension and extension of r_m and actual growth ra(es(r)are analysed, and an index(r/r_m)is put forward for quantifying the concept of ecological strategy. The relationship between tody weight of animals and r_m are quantitatively analysed.

What is Ecology:A Preliminary Approach to the Essence and Expressing Form of Ecology

Zhou Xiaoping

1991, (5):  62-64. 

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The author considers that ecology is an objective reality. It is the structure formed by organism and its environment,as well as the function expressed by the structure. Three attributes of ecology, i.e., naturality, sociality and economy are preliminarily commented.