Table of Content

25 July 1990, Volume 1 Issue 3

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Articles

Quantitative evaluation on the influence of environmental factors on timber production of Pinus tabulaeformis

Xiao Yu

1990, 1(3):  193-200. 

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Using the method of multivariate statistical analysis, this paper quantitatively evaluates the influence of environmental factors on the timber production of artificial Pinus tabu laeformis forests in Shanxi province. In the group of geographic-topographic-edaphic fac tors, soil type is the prime important factors in affecting the growth of Pinus tabulaefor mis, its contribution amounts to 38.75%. In the group of climatic factors, mean tem perature in July is most important in South Shanxi and Qinling Mountains, it contributes 34.46%; and in North Shanxi, the prime important factor is annual precipitation, whose contribution amounts to 27.80%. Based on the effect of environmental factors and the performance of stands, three growing zones of Pinus tabulaeformis in Shanxi province are devided, and each zone is characterized by environmental factors and growing performan ces.

Modelling on the relationship between rainfall and interception of forest canopy

Kong Fanzhi, Song Bo, Pei Tiefan

1990, 1(3):  201-208. 

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According to the observed data and relevant references, an in-depth analysis on the pro cess of canopy interception is given, and analogized with the curve of up-saturation function which based on the theory of solution adsorption in physicochemistry, a set of new models on the relationship between the rate of rain falling to the forestland, the rate of interception, the intercepted quantity and the rainfall outside the forest is presented. Three parameters μ_m、 P₀ and k in the models have definite hydrological significance. As we compare the results from the model with observed data, the consistency is quite sati sfactory. And all of these would have some significance for further canopy interception researches.The formula of the rate of rain falling to forestland.

Accumulation and biological cycle of elements Ca and Mg in Bruguiera sexangula community of Hainan Island in China

Lin Peng, Lin Mingxiang

1990, 1(3):  209-213. 

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This paper is a part of studies of mangrove forest in Dongzhai harbour of Hainan Island in China. It deals mainly with the accumulation and biological cycle of elements Ca and Mg of 55-year-old Bruguiera sexangula community. The main results of the study are as fallows: 1) The total amounts of Ca and Mg in standing crop of this community were 3258.1kg·ha^-1 and 597.9kg·ha^-1 respectively among which, 1891.9kg·ha^-1 of Ca and 247.1kg·ha^-1 of Mg contained in the aerial part, and 1366.2kg·ha^-1 of Ca and 350.8kg·ha^-1 of Mg contained in the ground part. 2) In the biological cycles of Ca and Mg of this stand, 382.0kg·ha^-1 of Ca and 100.4kg·ha^-1 of Mg were annually uptook by the community, among which 250.7kg·ha^-1 of Ca and 80.4kg·ha^-1 of Mg were returned and 131.3kg·ha^-1 of Ca and 20.0kg·ha^-1 of Mg were retained. 3) The turnover period of Mg (8 yrs.) was faster than that of Ca (13 yrs.).

Flight ability of wintering generation lady birds Coccinella septempunctata L. and Harmonia axyridis Pall

Zhai Baoping

1990, 1(3):  214-220. 

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Studies on flight ability of seven-spotted lady beetle (SLB), Coccinella septempunctata L. and Asiatic lady bird (ALB), Harmonia axyridis Pall. are presented. Field-captured wintering generation beetles were flown on flight mills linked to a microcomputer data processing system.Variability of the flight performance among specimens was great. Al though 36.5% of SLBand 23.7% of ALBnever made a flight more than30 min., there were some individuals flying over 20 hr. in both species. The percentage of tested beet les made a sigle flight in excess of 6 hr. and 12 hr. was 9.4% and 1.2% in SLB, as opposed to 21.1% and 13.2% in ALBrespectively. With respect to the total amount of flight duration accumulated from the flights lasting longer than 30 min., there were 20.0% of SLB and 47.4% of ALB exceeded 6 hr.; and the proportion of individuals ex ceeding12hr. was 7.1% in SLBand 28.9% in ALB. The females of ALBperformed the greatest flight ability during the vitellogenesis stage. The maxmum sustained flights and distances of 22.45 hr. and 94.464 km for SLBand 24hr. and 92.550km for ALBwere recorded. The maxmum speed of flight was 2m/s for both species.

Biological effect of pH values on 5 species of common leeches

Yang Tong, Li Jianqiu

1990, 1(3):  221-224. 

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Biological effect of pHvalues were tested for 24-96 hours to five species of leeches (Hirudinea)Glossiphonia lata, Erpobdella octoculata, Whitmania laevis, Whitmania acra nulata and Hirudo nipponia in Wuchang using bioassay method. The results indicate:3 species(Whitmania laevis, Whitmania acranulata and Hirudo nipponia)in rice fields are more sensitive to the variation pHvalues thanspecies (Erpobdella octoculata and Glossiphonia lata)in the water near lakeside, among them, Whitmania acranulata has the highest sen sitivity(pH6.0-7.2), Erpobdella octoculata has the widest enduring limit(pH 4.0-10.5); as pHvalue raised to 9.5, the percentage of mortality of 3 species in rice fields reached 40% or more, among them, Hirudo nipponia was 70%; as pHvalue dropped to 3.0, 2 species in the water near lakeside all died in24 hours, but Hirudo nipponia only had the mortality of 10%.

A research method of using 'insect (or mite) days' for establishing time dynamic EIL

Qin Yuchuan, Cai Ninghua

1990, 1(3):  225-230. 

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With european red mite (Panonychus ulmi) as an example, the author inquired into the method of using 'insect (or mite) days' for establishing time dynamic EIL. It is consi dered that firstly, the EILfrom 'insect (or mite) days' contained the fundamental information of insect or mite injury; Secondly, 'insect (or mite) days' EILis a time dynamic one, not belonging to an one-time EIL; Thirdly, the modelling needs rot consider the survival rate of injurious insect or mite.

Transferring model of Se in soil-wheat food chain and its application

Li Shuding, Zhang Shaolan

1990, 1(3):  231-236. 

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Transferring and distribution patterns of Se in soil-wheat system were studied using Setracer. Available coefficient of soil Se by wheat (SA) is 0.3—1.9, it varied with soil types. Distribution coefficient of soil Se in solid and liquid phases (Kd) is 141—395. it is shown that Se is adsorbed strongly by soil. The order of Kd is Dark brown forest soil>Black soil>Meadow burozem. Concentration coefficient of soil Se for wheat is 0.09—0.14. It is demonstrated that wheat does not belong to the crops which can concentrated Selenium. Selenium is easily transferred in various organs of wheat , its CF value is more than1. Transferring model of Se in soil-wheat food chain was put forward by au thors, and level of soil available Se was avaluated . The results show that available Se is sufficient in brown burozem, but insufficient in black soil and dark brown forest soil. The amount of Se absorbed by per capita per day is 26.6 g in the disease area , which is far less than the recommended value of 40—240 g in China.

A preliminary study on C₃ and C₄ plants in the Northeast stepps and their ecological distribution

Yin Lijuan, Zhu Ling

1990, 1(3):  237-242. 

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C₃ and C₄ forage plants in the Northeast stepps were identified by using the ratio of RuBPCase activity/PEPCase activity. 35 species among the total 45 tested species were first identified. The Kranz structure was observed only for Gramineae plants. On the basis of C₃ or C₄ plants identified, 11 dominant species were selected to study their geographical distribution, phenological spectrum and relationship between their relative dominance and soil pHvalue or salt content. The results showed that there were 30 species of C₃ plants from 24 genera in10 families and 15 species of C₄ plants from 9 genera in5 families. In comparison with C₃ plants, C₄ forage showed a higher relative growth dominance in the season with high temperature, strong radiation and high precipitation and a higher relative distribution dominance at lower latitudes and salt alkalized region. The correlation coefficient between relative dominance of C₄ forage and soil pHvalue, or salt content was 0.826 or 0.760 respectively, but that for C₃ plants was negative.

Relationship between photosynthesis and nitrogen metabolism in the nodules of Alnus tinctoria Sarg

Zou Hua, Ding Jian, Su Fengyan

1990, 1(3):  243-247. 

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In the symbiotic system of actinorhizal plants and Frankia, nitrogenase activity is closely relied on the photosynthetic products of plants. To approach this physiological relativity, we have synchronously examined the photosynthetic rate, N₂ase activity, NH₄⁺, reducing sugar and total nitrogen contents in the nodules of the same plant of Alnus tinctoria Sarg at different time during the day. The results indicated that the maximum of N₂ase activity appeared behind the maximum of photosynthetic rate. This suggested that it was photosynthetic products that influenced the N₂ase activity, and the transport of the products from leaves to nodules took a certain time. In the nodules, when NH₄⁺ and redu cing sugar contents decreased, the N₂ase activity increased and at the meanwhile, the total nitrogen content increased too. These phenomena had been discussed. It can be con cluded that reducing sugar as the derivatives of photosynthetic products influences immediately on nitrogen fixation and can provides not only the energy for nitrogen fixation, but also the carriers for NH₄⁺ which was the first product of nitrogen fixation.

A study on sulfate reduction in salt marsh near the estuary of obsolete Huanghe Rivel

Sun Bingyin, Jing Meide

1990, 1(3):  248-253. 

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In this paper, sulfate reduction rate in salt marshes near the estuary of obsolete Huanghe River was reported. The rates were measured for 2 years (1980—1988) in salt marsh ve getated with two species of Spartina by isotopic label technique. Results indicated that the integrated annual rate is about 77.75mol SO₄^2-·m^-2·yr^-1 in Spartina anglica peat and about 110.3mol SO₄^2-·m^-2·yr^-1 in S. alterniflora peat. Sulfate reduction rates in these experimental fields are probaly higher for three reasons: 1) underground production of Spartina spp. provides a large annual amount of organic substrates over a depth of 20 cm; 2) sulfate is rapidly resuplied to the peat by infiltrating tidal water, so that sulfa te depletion never limits the rate of reduction; 3) sulfate concentration remains below to xic levels. FeS₂ is a main end product of sulfur reduction, while FeSis not. FeS₂ acts as a temporary store of reduced sulfur, changing with seasons in its cocentration. The important role of sulfate reduction in mineralizing organic carbon and the significance of energy flow in salt marsh ecosystem were discussed.

Numerical classification and ordination of plant communities in the alpine tundra of Mt. Changbai

Qian Hong

1990, 1(3):  254-263. 

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In this paper, the plant communities in aJpine tundra of Mt. Changbai were studied using the methods of DCAordination (DECORANA program)and TWINSPANpolythetic hierarchical divisive classification (TWINSPAN program).The results show that 59 types of plant communities in the alpine tundra of Mt. Changbai were basically arranged along a soil-water gradient of the second axis in DCAordination and could be classified into 12 groups by TWINSPAN. In addition, a comparison of the results by DCA and TWINSPAN and by traditional classification was made in this paper.

Landscape ecology——the developement of a holistic concept

He Hongshi, Xiao Duning

1990, 1(3):  264-269. 

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Landscape ecology was a holistic concept when it was firstly advanced by C. Troll in1938 and it had been neglected for about 30 years. Three factors promoted its revive in early 70s: 1) techniques of remote sensing, 2) the deepen and popularize of ecology, 3) the tendency of multi-dimesional study. With the characteristics of two research direc tions, horizonal and vertical direction, it obsseses the advantages to carry out study of integration, and is being payed more attentions by many ecologists and geologists. They found it a useful way to resolve reginal problems. Landscape ecology is considered as a new branch of ecology by more and more scientists, some even think it as a new science to face the future. In our opinion, landscape ecology is at its very beginning, and will have a long way to be a new science. Its research scope should cover from basic ecolo gical system to a region.

Simulation and modelling of crop production

Shen Siyuan

1990, 1(3):  270-276. 

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According to the ecological factors which limit the productivity of agroecosystem, crop production system and productivity model can be distinguished and established. This paper paid more attention to compartment mechanistic mode), spatial variabic model and statistic model. Each of these models is useful to predict crop production, in agroecosy stem at a certain level.

Studies on the ecology of virus in environmental media

Wang Deming

1990, 1(3):  277-286. 

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Viruses are responsible for a variety of diseases in human bodies as well as animals and plants of economic importance. Depending on environmental conditions, many of these viruses can survive in environmental media for several hours to several months.This can result in water, soil and aerial dissemination of such infectious agents over distances of several kilometers. Studies show that sd:\PDF\.pdfuch viruses, at least of enteric nature which are shed in feces, can easily survive under present methods of sewage treatment.Raw sludge land disposal can present a risk of human illness through enteric virus contamination of market fruits and vegetables harvested from sewage-irrigated fields. Because as little as one tissue-culture infectious dose of virus may cause an infection in humans, it is im portant to eliminate even minute numbers of these microorganisms from environmental me dia, especially drinking water and food. Current indicators are not accurate monitors of fecal pollution and do not adequately reflect the presence of human enteric viruses. Coliphages are readily recovered from stwage from all parts of the world. In most cases, the persistence of coliphages in surface water, groundwater and sewage is greater than that of human enteric viruses and enteric bacteria. Coliphages have a number of unique characteristics which permit selective analytical techniques. In some ways, coliphages may serve as indicators when assessing the likely fate of human enteric viruses. Further research needs concerning the ecology of virus in China has been suggested by the author.

Space distribution type of Trifolium pratense on the Hongchiba grassland

Hu Minqiang

1990, 1(3):  287-288. 

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Using five distribution type indexes, this paper analyses the space distribution of Trifo lium pratense on the grassland of the Hongchiba district and gets the conclusion that its distribution type is the aggregation one and this type is related to the diffusion form of Trifolium pratense seed and the environmental condition.