Table of Content

25 March 1997, Volume 8 Issue 2

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Articles

Niche dynamics of Castanopsis fargesii population

Du Daolin, Su Jie, Liu Yucheng

1997, 8(2):  113-118. 

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The successive series of forest communities at Mt.Jinyun of Shichuan province are sampled and the niche's characters and dynamics of Castanopsis fargesii population are studied by the methods of Levins' niche breadth(B), Feinsing and Spears' niche breadth(PS), and Levins' and Petraitis' niche overlapping. The results show that Castanopsis fargesii population is a dominant one in the evergreen broad leaved forest, which is at the climax stage in the succession of forest communities at Mt. Jinyun. Its niche breadth is increased with the successive process of the forest community, and the utilization degree of its resource shows the shape"∧".As for the niche overlapping between Castanopsis fargesii and other 14 dominant populations of five forest communities at Mt. Jinyun, only Castanopsis fargesii population specializedly and fully overlaps with populations Castanopsis carlesii var. spinulosa, Symplocos lancifolia, Symplocos setchunensis,Elaeocarpus japonicus,Neolitsea aurata var. glauca,Lindera kwangtungensis,Gordonia acuminata, Daphniphyllum glaucescens,Cunninghamia lanceolata and Pinus massoniana in typical mixed coniferous and evergreen broad leaved forest, and with populations Castanopsis carlesii var. spinulosa, Symplocos lamcifolia and Cunninghamia lanceolata in coniferous forest.

Distribution patterns of main tree species in Tilia broadleaf Korean pine forest on northern slope of Changbai Mountains

Sun Weizhong, Zhao Shidong

1997, 8(2):  119-122. 

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In this paper,variance/mean test,χ² test of Poisson distribution and χ² test of negative binomial distribution are used simultaneously to detect the distribution patterns of main tree species in Tilia broadleaf Korean pine forest sampled by two methods, and the results are tested by location drawing with sample size of 1 hm². The results show that sampling with a size of 5 m×5 m is fit for arboreous trees. Pinus koraiensis,Tilia amurensis,Fraxinus mandshurica,Maackia amurensis and Acer mandshurica belong to an aggregate distribution,and Quercus mongolica and Ulmus propinqua to a stochastic one.

Light-ecological field of Larix leoptolois canopy

Li Shuren, Zao Yong, Yan Zhiping

1997, 8(2):  123-126. 

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The light ecological field of Larix leoptolois canopy is studied by means of neighboring disturbed models and shading effect method. Based on shading effect among various growth classes of Larix leoptolois, the shading coefficient table is drawn up,and the shading models of different growth classes are put forward.The results show that the projection of single Larix leoptolo is canopy is an ellipse with east west as its long axis, and south north as its short axis between₇ am to 5 pm. The individual plant shading intensity is the sum of the shading effects of other trees within the ellipse in the forest. The higher the shading field intensity, the stronger the light ecological effect, and the worse the tree growth.

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

Zhang Jilin, Kang Lixin, Ji Yonghua

1997, 8(2):  127-133. 

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The studies show that within the scope of 27 H from sheltered side of farmland windbreak, forest net has the functions of reducing cotton lodging and its yield loss to a certain extent.The effective protection zone ranges from 0.42 to 23 H, and the maximum effective zone for unginned cotton yield and gin turnout percentage is from 10 H to 13 H. Compared with damaged zone, protection zone has an increase of 45.01% for unginned cotton yield and 52.69% for ginned one. Within the whole forest net, the unginned cotton yield is increased by 29.9%, and the gined one by 35.06%.

Relationship between root system characteristics and drought resistance of wheat populations in semiarid region

Duan Shunshan, Gu Wenxiang, Zhang Dayong, Li Fengmin

1997, 8(2):  134-138. 

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Afield experiment with five spring wheat (Triticum aestivum) varieties 8275(A),79157(B),8832(C),8624(D) and DX24(E) which have different drought resistance shows that the average root density in 0～120 cm soil layer is 66 μg·cm^-3 for A,104 μg·cm^-3 for B,137 μg·cm^-3 for C,102 μg·cm^-3 for Dand 99 μg·cm^-3 E, and their total root weight is 78.7,124.3,164.3,121.8 and 118.7 g·m^-2 ,respectively.The grain yield of these five varieties are respectively 201,207,141,218 and 190 g·m^-2 .When water is a primary limiting factor, the drought resistance of wheat is worse for those with large root systems,and an intense competition for water is existed among individuals;but is better for those with small ones, and no competition for water is existed.

Potential productivity of dryland spring corn on Loess tableland

Liu Wenzhao, Wei Xiang, Li Yushan

1997, 8(2):  139-142. 

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According to the field experiments on Changwu tableland of southern Loess Plateau,the function of corn yield response to water could be described as: Pw=1.00-5.293(1-k)² ,where Pw is the potential productivity index of dryland corn, and k is the water stress index, a ratio of water consumption to water requirement during the entire growth period of dryland corn under high soil fertility conditions.The k value varies from 0.78 to 1.10,and its theoretical upper limit is related to the local potential evapotranspiration.The average Pw was 0.87 from 1985 to 1988.Its long term value has a similar fluctuating trend with the short term one over the four years.The former was 11247 kg·hm^-2,and the latter was 7696 kg·hm^-2.The actual yields in the field experimental region during recent years approach to the short term value,due to the high input of fertilizers and the improvement of crop varieties.

Effect of intercropping on soil erosion in young citrus plantation —— a simulation study

Wu Jianjun, Li Quansheng, Yan Lijiao

1997, 8(2):  143-146. 

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With non intercropping as a control,milkvetch, mixture of ryegrass and milkvetch and ryegrass were respectively intercropped with young citrus trees and the relationships of underlying soil surface with rainfall and soil erosion were analyzed and simulated. The amount of eroded soil from intercropped plots was greatly reduced,being only 14.7% as compared with control on the average.The amount of eroded soil is decreased exponentially with increasing order of rain course and increasing coverage of soil surface.

Energy and nutrient analysis of upland phytofuel species

Chen Rongjun, Ronald D. Hill, Richard T. Corlett

1997, 8(2):  147-150. 

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In this paper, the calorific value and nutrient concentration of most phytofuel species in Hong Kong and Guangdong Province are determined and their quality as fuel is assessed.The calorific value of woody species ranges from 17.13 to 23.51 kJ·g^-1 , while that of herbaceous species ranges from 15.13 to 21.47 kJ·g^-1 . The species commonly used for domestic fuel in Guangdong and Hong Kong have a calorific value of over 20 kJ·g^-1 . Species with lower Nconcentration are more suitable for fuel, because less Nis removed from upland ecosystems and less NO_x is emitted to the atmosphere. Woody species have a Nconcentration of 4.67～10.90 mg·g^-1 , whereas herbaceous species, 3.55～14.59 mg·g^-1 . Pand Kricher species are less desirable fuels, since more nutrients are removed from hillsides. The Pconcentration varies from 0.17 to 1.05 mg·g^-1 , and K, from 3.98 to 23.00 mg·g^-1 . Woody species are not significantly different from herbaceous ones in calorific value and nutrient concentration.

Species diversity during desertification on Kerqin Sandy Land

Chang Xueli, Wu Jianguo

1997, 8(2):  151-156. 

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This paper analyes the changing characteristics of species diversity during the process of desertification in Kerqin,Inner Mongolia.Based on the frequency of species occurrence and the life form composition of species at different stages of desertification,the characteristics of species colonization and extinction are discussed. The species diversity indices show that desertification is a process of biodiversity loss.In particular, specialized species are wipped out first, rare species vanish second, and common species begin to disappear.Change in life form composition indicates that perennial herbaceous and scrubby plants are severely affected by desertification,whereas annuals and semi shrub species occur at all stages of desertification.The extinction rate of plants in this area is higher than their colonization rate.

Comparison of characteristics of different provenance Leymus chinensis grown under different water-stress conditions

Ren Wenwei, Qian Ji, Zheng Shizhang

1997, 8(2):  157-160. 

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Seeds of Leymus chinensis collected from different areas of Inner Mongolian are cultivated under different water stress conditions, and characteristics of their one year old plants are compared. The results show that the characteristics of Leymus chinensis have different stability. Through analyses of qualitative cross over interaction, it is suggested that L.chinensis is a kind of drought enduring plant, but its growing is far better under full water condition than under lack water condition. Of all kinds of L.chinensis, A Qi has the most stable characteristics, and of all characteristics, the asexual reproduction (such as tillers, buds of root stock) is more stable than the nutrition (such as plant height, leaf length).

Development of Kira's indices and its application to vegetation climate interaction study of China

Ni Jian

1997, 8(2):  161-170. 

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Based on the concept of Kira's thermal indices and aridity/humidity index by the limit of monthly average temperature 5℃, the biological thermal indexes by the limit of monthly average temperature 10℃, including biological warmth index (BWI) and coldness index (BCI),are put forward,and Kira's aridity/humidity index is modified to biological aridity/humidity index (BK) . According to the records of 689 meterological stations,relationships between the distribution of main vegetation types of China and the thermal and aridity/humidity factors are analyzed. There exists a definite interactions between vegetation and climate. The scatter graphs of biological warmth index, coldness index and aridity/humidity index kindly show the relationship and pattern between vegetation types and climate. The biological warmth index (>10℃) not only indicates to the geographical distribution of forestry vegetation and classification of thermal climatic belts in eastern China, but also indicates the relations between vegetation and climate in alpine and subalpine regions of southwest China. Biological coldness index is a good index to distinguish the southern subtropical and tropical belts. Biological aridity/humidity index synthetically got from biological warmth index and precipitation has a kind value to analyse the relations between vegetation and water thermal factors in arid and semiarid areas of northwest China and also in the whole country.

Field measurement of N₂O flux from soybean plant and effect of light on it

Yu Kewei, Huang Bin, Chen Guanxiong, Wu Jie

1997, 8(2):  171-176. 

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The N₂O flux from soybean plant measured by closed chamber method under field condition shows that there exist two peaks of N₂O emission at soybean's seedling and flowering stages,respectively. The general pattern of diurnal variation in N₂O flux from soybean plant is an emission peak in the morning and a valley in the afternoon,which is not altered by fertilization.The average N₂O emission rates are 2.27 and 1.28 μgN₂Om^-2 ·h^-1 for fertilized and control plots,respectively. Soybean plant has a lower N₂O flux under strong light condition (in the level of 10⁴lx), even absorbing the atmospheric N₂O.But under weak light condition (in the level of 10³～10²lx),N₂O flux from soybean plant is higher.

Effect of nutritional condition on N₂O emission by crop seedlings——a sand liguid cross culture study

Chen Xin, Shen Shanmin, Zhang Lu, Wu Jie

1997, 8(2):  177-180. 

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With separated compartment culture technique, the study confirmed that N₂O in soils has a great interference on the measurement of N₂O emitted directly by some plants such as maize and sorghum. The interference can be effectively eliminated by means of sand liquid cross culture technique. With this technique, the intensity of N₂O emitted directly by seedlings of both soybean and maize is accurately determined, and the correlations between Nand Pnutritions on the one hand and N₂O emission and NO₃^--N concentration of crop seedlings on the another hand are obtained.

Effect of temperature on the growth and development of Agasicles hgrophila

Wu Zhenquan

1997, 8(2):  181-184. 

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Results from experiments under controlled temperature showed that there exists a functional relationship between the development durations of egg, larvae and pupae of Agasicles hgrophila and the temperature.From 22 to 32℃,the development durations are obviously shortened with increasing temperature.The larval period has three instats and endures 8.8 days.The life span of adult is related to temperature and sex,and the females live longer than the males.The period of pre oviposition varies from 1.5 to 5.0 days, and that of oviposition from 11.5 to 116.0 days.The initial temperature of egg,larvae and pupae development is 12.4 and 12℃, and the effective accumulative temperature of them is 69.192 and 125℃,respectively.

Prediction on occurrence of Pandermis heparana

Yang Chuncai, Zhao Yiqin, Wang Chengyang

1997, 8(2):  185-188. 

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Pandermis heparana is an insect seriously harmful to the flowers, shrubs and trees in garden. Its larvae feed on their tender buds and leaves, resulting in the decrease of the ornamental value of these plants. In order to control the pest,it is very important to predict accurately on the occurrence of its various growing phases.After raising this insect at varying temperature indoor for more than one generation,the necessary initial development temperature(C) and effective accumulated temperature (K) were found for each phase of its development:egg stage C= 14.83 ±1.38(℃),K=64.11±6.68(DD);larval stage C=15.24±1.41(℃), K=252.58± 21.40 (DD);pupal stage C=15.06±1.01(℃),K=68.94±5.48(DD);a generation C=15.28±3.31(℃), K=382.47±26.92(DD).Based on these parameters,the prediction is quite successful.

Factoral analysis on alate rate of Macrosiphum granarium and Schizaphis graminum adults

Zou Yunding, Huang Shixiang, Geng Jiguang, Chen Gaochao, Meng Qinglei, Ma Fei, Wang Gongming, Hu Lijuan, Ji Jin

1997, 8(2):  189-193. 

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The factoral analysis shows that among three wheat varieties fested,the difference of the alate rate of M.granarium adults is not significant,and under two N application levels,the alate rate of M.granarium and S.graminum adults also hasn't any significant difference.JHanalogs with a concentration of 0.5% or 0.25% can produce a remarkable effect on the alate rate of M.granarium adults.The alate rate of M.granarium adults is closely related to the contents of leucine,tyrosine,phenylpropionic acid,lysine,proline,γ aminobutyric acid,amide nitrogen and water soluble proteins in wheat plant,while that of S.graminum adults is closely correlated to the content of crystine.

Affecting factors on hydrogen production by photosynthetic bacteria Rhodopseudomonas

Zhu Heguang, Zhao Yilin, Shi Jialiang

1997, 8(2):  194-198. 

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8 strains of photosynthetic bacteria Rhodopseudomonas were used to study the effect of bacterial initial activity, illumination intensity, carbon sources, strain differences on their hydrogen production. The results show that different strains are differed significantly in carbon source utilization,but they can utilize sodium lactate very well. Bacteria initial activity affects hydrogen production to a certain extent,and the hydrogen production activity of the bacteria is slightly higher in its stable growth phase than that in exponential growth phase.Illumination intensity has a significant influence on hydrogen production. Higher illumination intensity leads to higher hydrogen production rate.Strain B₂₁ of Rhodopseudomonas isolated from organically polluted areas of Shanghai has a very high hydrogen production rate, being 14.7ml·h^-1 ·g^-1 (dry cell) with the carbon source of sodium lactate (50 mmol·L^-1), nitrogen source of sodium glutamate (10 mmol·L^-1), illumination intensity of 6000 lux, and the temperature of 30℃.

Predator species of fishery resources enhancement and their predation on enhancement species in Laizhou Bay of Bohai Sea

Tang Qisheng, Wei Sheng, Jiang Weimin

1997, 8(2):  199-206. 

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Based on the analysis of stomach contents of nearshore predator species and on the trawl survey of marine resources covering large area in the Bohai Sea,the composition and distribution of the predator species, and their harm to the enhancement species of fishery resources in the Laizhou Bay of Bohai Sea are studied. The results indicate that the juveniles of perch(Lateolabrax japonicus),Nibea albiflora, Enchelyopus elongatus and Chaeturichys spp.are the main predators of the juveniles of penaeid shrimp and Liza haematochelia, etc.,which are the species of enhancement in Bohai Sea. Predation occurs mainly in nearshore waters. Among the predators, perch is the most important one whose predation takes place mostly in July,and the length of juvenile penaeid shrimp consumed ranges from 3 to 7 cm.Due to the fact that predation on the enhancement species takes place mainly in nearshore and waters where both predator and enhancement species are densely distributed and overlapped, the strategy of avoidance to the predators will be a feasible approach of protecting released juveniles of enhancement species in the selection of enhancement release regions.

Ecological effect of compound pollution of heavy metals in soil-plant system Ⅰ.Effect on crop, soil microorganism, alfalfa and tree

Wu Yanyu, Wang Xin, Liang Renlu

1997, 8(2):  207-212. 

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The ecological effect of Cd,Pb,Cu,Zn and As compound pollution in soil plant system was studied in field plots. The designed concentration of pollutants was based on soil environmental standards or guidelines. The results show that there are interactions among these five elements, which cause a toxic effect on the ecosystem. The activity of soil microorganism is inhibited at low dose. At high dose, the crop yield is decreased by 10%, and on acid soil,by 50%. Alfalfa and tree are also yield decreased.

An indicating framework for ecosystem sustainability

Hu Dan

1997, 8(2):  213-217. 

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Ecosystem sustainability is defined as the capacity of ecosystem in sustaining or maintaining the health and evolution of its components, structures and functions which consists of the capacities of ecological integrity, self maintenance, self regulating and self organization. As ecosystem sustainability is emerged by its components, structures and functions, a methodological basis of measurement should be established by their identification and assessment. In this paper, an indicator based framework of measurement with 12 items and more than 30 variables is presented to indicate the essential dynamic attributes of sustainable ecosystem. Although such an indicator based approach is very necessary for the measurement of ecosystem sustainability, it needs to be combined with integrated methods of measurement to establish a complete system for measuring ecosystems of sustainability.

Ecolgical effect of heavy metals on soil microbes

Gong Ping, Sun Tieheng, Li Peijun

1997, 8(2):  218-224. 

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In this paper,the ecological effect of HMs on soil microbes is reviewed,based on the analyses of the influence of HMs on soil microbial activities, populations and communities; the factors affecting HM toxicity on soil microorganisms; the criteria for evaluating HM toxicity on soil microorganisms;the resistance and adaptation of soil microorganisms to HMs; and the variety of HM toxicity.