Table of Content

25 April 1996, Volume 7 Issue 2

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Articles

Spatial distribution pattern of natural Pinus sylvestriformis population with same age

Hu Yuanman, Xu Wenduo, Zheng Yuanrun

1996, 7(2):  113-116. 

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Studies on the history and size structure of Pinus sylvestriformis population show that the DBH of the population is submitted to normal distribution (N 16.87, 6.08²), being natural population with same age. Its spatial pattern has a higher evenness, and tends to a random or even distribution. The dynamics of distribution pattern shows a transformation from random to even distribution.

Dynamics of cycling regeneration of Gordonia acuminata population

Li Xuguang, Chen Aixia, He Weiming

1996, 7(2):  117-121. 

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Studies on seed rain, seed pool, seed germinating process and seedling growth of Gordonia acuminata population show that its regeneration process can be divided into gap, transition, optimal and terminal phases. The population is characterized by a larger temporalspatial scale cycling regeneration during its regeneration process. Competition for light resource is one of the main forces of cycling regeneration, which is closely related with the ecological adaptive strategy of the population.

Ecological engineering of shelter forest construction on mud seashore of north China

Li Shaozhong

1996, 7(2):  122-128. 

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The study of tree species selection, soil amelioration and afforestation in ecological engineering of shelter forest construcation on mud seashore of north China shows that Fraxinus velutina, Populus 'popularis', Robinia pseudoacacia and Salix 109 can be planted on light saline-alkali soil, Elaeagnus angustifolia, P.'popularis', R. pseudoacacia,F. velulina and salt-enduring strain of P.'Liaohe' on medium saline-alkali soil after burying sand,E. angustifolia and salt-enduring strain of P. 'Liaohe' on soda-salinized soil after burying fragments of rice stalk, and Tamarix chinensis and E. angustifolia on heavy saline soil after soil amelioration and soil engineering.

Theoretical and experimental studies on drag distribution in multi-row windbreak

Guan Dexin, Wang Shun, Zhu Tingyao

1996, 7(2):  129-133. 

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The drag distribution model in multi-row windbreak is presented in this paper. Wind tunnel experiment results on three types of windbreaks with different section forms are used to test the model, and its application in windbreak plantation is concisely analysed.

Simulation of canopy interception by Mongolian pine

Zeng Dehui, Pei Tiefan, Fan Zhiping, Jiang Fengqi, Zhu Jiaojun

1996, 7(2):  134-138. 

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Canopy interception is one of major components of water balance in forest stand. Each of four major factors affecting canopy interception(I) of Mongolian pine,i. e., rainfall intensity(R_i) and quantity(R_q), leaf area index(LAI) and dry degree of twigs and leaves before raining(Dd), is divided into five levels. Twenty-five experiments are carried out in laboratory on the basis of orthogonal design, and the effects of all factors on interception are analyzed. Among the factors, LAI has the most remarkable effect. Equations are established between I and LAI, R_i and R_q. There is no distinct difference between modeling value and experimental data, and hence, the equations can be used to calculate the interception rates of different Mongolian pine stands.

Accumulation and distribution of Cr, Ni and Mn in Avicennia marina mangrove community at Futian of Shenzhen

Zheng Wenjiao, Lin Peng

1996, 7(2):  139-144. 

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The accumulation and distribution of Cr, Ni and Mn in Avicennia marina mangrove community at Futian Mangrove Nature Reserve of Shenzhen are studied. The results show that the Cr, Ni and Mn contents in forest soil are increased from bottom to surface layer,and in the surface layer (depth 0～30 cm), their contents are 7.79, 25.0 and 537μg·g^-1 and storages are 1099. 86, 3450. 00 and 74106. 00 mg. m^-2, respectively. Cr, Ni and Mn contents in different parts of the plant are 0.28～ 0.75,0.43～7.65 and 25～1552μg·g^-1, and their storages in the community are 6. 06, 20. 76 and 1631. 17 mg· m^-2, respectively. The accumulation index of plant to soil is in the order of Mn> Ni≈Cr. The annual net retention accumulation of Cr, Ni and Mn in the community is 0. 43, 1. 43 and 107. 98 mg· m^-2,respectively. The storage of the elements in residues is 78. 00 μg· m^-2 for Cr, 1536. 33μg·m^-2 for Ni and 405. 54 mg· m^-2 for Mn. The Cr, Ni and Mn storages in leaves of various types of communities are in the order of Avicennia marina>Aegiceras corniculatum>Kandelta candel for Cr and Ni, and K. candel>A. marina> A.corniculatum for Mn.

Isolation and identification of extract from Casuarnia equisetifolia branchlet and its allelopathy on seedling growth

Deng Langui, Kong Chuihua, Luo Shiming

1996, 7(2):  145-149. 

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Casuarnia equisetifolia is an important tree species for shelter belt at the seashores of South China, but it degenerates quickly. The potential cause of its degeneration is discussed from the viewpoint of allelopathly. The results show that allelochemicals produced by C. equisetifolia can inhibit the growth of its seedlings. Five allelochemicals from C. equisetifolia branchlet are isolated and identified by means of HPLC, IR and NMR. They are kaempferol-3-α-rhmanoside, quercetin-3-α-araboside, luteolin-3', 4'-dimethoxy-7-β-rhamnoside, kaempferol-3-β-dirhamnoside and quercetin-3-β-glucoside. The first three of them can inhibit the growth of seedling, and especially that of root.

Biomass of soil animals in larch plantation

Zhang Xueping, Cul Guofa, Chen Peng

1996, 7(2):  150-154. 

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The study on soil animal biomass in larch plantation with different ages shows that in different stands, soil macroanimals occupy 41.6～64.0% of the total, middle-small size animals 24.4 ～ 39.0%, and hygrocolous animals 8.9～25%. Among them, earthworm is the maximum, nematode is the medium, and enchytraeidae is the minimum. Soil animal biomass is positively related to the litter, plant coverage, soil pH, soil moisture content and soil organic matter.

Physiological response of Aneurolepidium chinense seedlings on NaCl stress and mitigation effect of external ABA on it

Wang Ping, Yin Lijuan, Li Ji,ong

1996, 7(2):  155-158. 

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Studies on the growth and metabolism of Aneurolepidium chinense seedlings show that under NaCl stress, their growth is inhibited, while the relative permeability of leaf cell membrane is increased, which induces the accumulation of inorganic Na⁺ in leaf. The leaf content of proline is increased, but that of chlorophyll is decreased. External ABA can promote the uptake of K⁺ by A.chinense,but inhibit the uptake of Na⁺, weaken the toxicity of Na⁺, enhance the stability of leaf cell membrane and the photosynthetic capacity and permeability regulation ability of leaf, and increase the activity of plant growth and metabolism and the content of chlorophyll.

Quantitative analysis of growth and regeneration of Dactylis glomerata tiller tuft on subtropical mid-mountain sites

Yang Yunfei, Fu Linqian, Zhu Lin

1996, 7(2):  159-163. 

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Quantitative analysis of growth and regeneration characters of Dactylis glomerata tiller tufts shows that during its blooming and vegetative growth periods, the number of tillers per tuft is linearly increased with increasing tuft size. The living and dead biomass of the tuft is positively correlated to its size and tiller number f respectively. The mean weight of each tiller is respectively decreased hyperbolically and power-functionally with increasing tuft size and tiller number,and the earing rate is linearly decreased with the increase of them. The strategy for the growth of tuft is to throw most part of energy into its reproductive growth at the earlier growing stages.

Lowland agroecosystem models in Dongguan suburbs

Chen Rongjun, Luo Shiming

1996, 7(2):  164-168. 

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The structure and economic effect of lowland agroecosystem models in Dongguan suburbs of Guangdong Province are studied. The major models there include integrated planting-raising model, animal rearing model, and high-bed and low-ditch vegetable growing model. The results show that integrated planting-raising model has a perfect function and a high work day value. It is suggested that according to eco-engineering principles, such essential components as fish culture and pig farming should be added to the continuous vegetable growing model to improve the holistic function of the ecosystem and obtain a sustainble effect.

Effect of post-flowering daylength on agronomic characters of soybean

Han Tianfu, Wang Jiming, Fan Binbin, Yao Wenqiu, Yang Qingkai

1996, 7(2):  169-173. 

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The effects of post-flowering daylength on the agronomic character, and the relationship between length of developmental stages and agronomic characters are studied under photoperiod-controlled conditions. The results show that long day can increase the dry matter accumulation and increase the seed yield provided the maturation is normal. The filling duration is positively related to the seed size and yield, and the durations of flowering and podding are important for the yield as well. It is proposed that in northeast China, the long day before and during flowering and podding of soybean is favoring of the dry matter accumulation and the production of more flowers and pods, while the quickly shortened daylength after early filling can enhance the translocation of photosynthates to seeds and hasten seed maturation.

Transformation mechanism and availability of nutrients in albic soil-plant system———Ⅰ.Phosphorus utilization rate in albic soil: a tracing study

Li Fayun, Gao Ziqin

1996, 7(2):  174-178. 

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The tracing study with ³²P isotope shows that the supply of phosphorus in topsoil is insufficient and the amount of available phosphorus in Aw soil is fairly lack. The utilization rate of phosphorus fertilizer in topsoil ranges from 6. 09 to 12. 35% and that in Aw soil is 13% or so. Application of organic fertilizer can increase the content of Olsen P in albic soil and mobilize potential phosphorus. Fertilizing feces is the best way to mobilize the potential phosphorus in soil. Olsen P is the reliable index to evaluate the phosphorus fertility of albic soil.

Rice field ecosystems in northern China Ⅰ. Structural study of rice-Azolla combination systems

Sa Fengyan, Wen Dazhong, Xu Qingde, Li Weiguang, Yang Yulan

1996, 7(2):  179-184. 

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The effects of different structures of rice-Azolla combination system on rice and Azolla productions are studied within a 5-years experimental period. The results show that Azolla production on rice fields is significantly increased with increasing Azolla inoculation.Though the Azolla production is increased on the fields with alternating wide and narrow row rice plantings, the rice yield is decreased by 3～7%. The structure with an equal row rice planting of 30cm and an Azolla inoculation rate of 325kg·hm^-2 (wet weight) is recommended for developing rice- Azolla combination system in northern China.

Energy dynamics of Heliocoparva armigeria population and its damage characteristics

Ge Feng, Ding Yanqin

1996, 7(2):  185-190. 

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Based on the population density, age structure, mortality and energy dynamics of Heliocoparva armigeria, its population production, ingestion and damage characteristics in eight different cotton field ecosystems are analysed. The results show that the energy production of H. armigeria population comes mainly from 3rd generation. The damaged amount of reproductive organs of cotton by the bollworm of 2nd, 3rd and 4th generations is respectively 11.83, 16.65 and 9.52 boils. m^-2. Along with the delay of cotton planting, the population production and ingestion of 2nd generation H. armigeria are decreased, and those of 3rd and 4th generation are increased. When the cotton intercropping is implemented, those are decreased for 2nd and 4th generations, and are increased for 3rd one.The ingestion-utilization efficiency of bollworm is increased with its increasing generation and its net ecological efficiency is maximum in 3rd generation, medium in 4th one, and minimum in 2nd one. The management strategies for bollworm is discussed in this paper.

Binomial sampling models for aphids on Brassica campestris ssp. chinensis and thir sampling precision analysis

Zhang Guangmei, Liu Shusheng, Feng Mingguang, Wu Xiaojing, Shi Zuhua

1996, 7(2):  191-196. 

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Field sampling of aphids on Brassica campestris ssp. chinensis was conducted in the suburbs of Hangzhou from 1990 to 1992. The mean aphid density (m, number of aphids per plant), variance (s²) and the proportion of plants with no more than T defined as tally threshold (=0, 1, 5, 10, 20, 30 and 40 per plant) aphids(P_T), are calculated. There are 57 estimates for Myzus persicae, 66 estimates for Lipaphis erysimi, and 38 estimates for their mixed populations. For each of two aphids and mixed population, the empirical relationship between m and P_T is developed using the parameters estimated from linear regression of ln (m) on In[-ln(P_T)]. The determination coefficients r², prediction variance of m from P_T, Var(m), and sample precision denoted as d obtained from different T values are compared. The results indicate that the optimal T for M. persicae should be 30 when its m≥ 10. and that for L. erysimi should be 10 when its m≥5. However,at low population densities. no adequate T values are found for either of the two aphids. Moreover, no acceptable T is found for the mixed population. It is suggested that the tally thresholds of 30 and 10 respectively for M. persicae and L. erysimi can be used for establishing binomial sampling models under relatively high population densities. The results also show that conventional binomial sampling (0～1) method produces unacceptable low levels of sampling precision, and could not be used in sampling of the two aphids.

Predation of Harmonia axyridis nymph on Schizaphis graminum

Zou Yunding, Geng Jiguang, Chen Gaochao, Meng Qinglei, Wang Gongming

1996, 7(2):  197-200. 

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The functional reaction of old Harmonia axyridis nymphs preying on wheat aphides shows the Holling Ⅱ type, i. e., preferring to feed on young aphid nymphs. The predation ratio is the lowest at 40C and the second at 10℃, being the highest at 25℃. At the range of 10～ 25℃, the relationship between predation ratio (y) and temperature (x) is y= 28.1303+ 2.6665x, and at 25～40℃,y=199. 9275 - 3. 642x. Under intraspecific interference, the relationship between predation ratio (E) and natural enemies density (P) is E=0.6897P^-0.7930, searching constant Q is 0.6897, disturbing coefficient M is 0.7930.The relationship between intensity of scrambling competition (I) and density of H.axyridis(P) is I= 0.0400+1.0383 logp.

Transferring and cycling of heavy metals in and out of poplar tree before and after its leaf fallen

Yu Guoying, Wu Yanyu, Wang Xin

1996, 7(2):  201-206. 

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The transferring of heavy metals in poplar tree during its leaf fallen mainly occurs in the parts of leaf-branch, root and trunk. 8～48% of As and Zn in leaf is transferred to bark and timber, and the storage of Cu, Ph and Cd is increased. The internal cycling rate of As and Zn occupies 40%, and the external one of Cd, Ph and Cu occupies 17～27% of their storage. The purification efficiency of soil heavy metals by plants is also discussed in this paper.

Chemotaxis of amino acids in root exudates from Eichhornia crassipes to its rhizospheric Enterobacter sp. F₂

Zhao Dajun, Zheng Shizhang

1996, 7(2):  207-212. 

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Many kinds of amino acids are found in root exudates from Eichhornia crassipes. F₂ can be strongly attracted to amino acids methionine, gamma amino butyric acid, glycine, alanine, aspartate, serine, valine, and leucine under concentrations from 10^-7 to 10^-2 mol·L^-1, some degrees to glutamate, threonine and histidine, but not to lysine, cysteine,arginine, tyrosine, proline, asparagine, glutamine, isoleucine, phenylalanine or tryptophan. There exists an optimium chemotaxic concentration range of each positive attractant. The fact that some amino acids caf f attract the bacteria,but others can not is one of the reasons why Eichhornia crassipes and F₂, can form a microecosystem.

Gene system ecology and its application

Lin Wenxiong, Lin Qunhui, Wu Zhiqiang

1996, 7(2):  213-217. 

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In this paper, the viewpoint of gene ecosystem is applicated to probe the behaviour ecology of gene and its general properties. It is proposed that gene is characterized by integration, connection, order and equilibrium. The perspective of gene ecology is also discussed.

Effect of seed treatment with extract B from Cyperus rotundus

Zhang Jianxin, Zhao Boshan

1996, 7(2):  218-220. 

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The study shows that soaking maize seeds with 100 and 1000 mg· L^-1 of extract B from Cyperus rotundus ca promote their seedling growth and uptake of N, P and K, but 10000 mg· L^-1 of the extract will inhibit P absorption. Soaking rice seeds with 1000 mg·L^-1 of it can inCrease the vitality of the root system of their seedlings, the uptake of P and K,the number of productive tiller and the yield of grain. At ear forming stage of rice, the activities of nitrate reductase and peroxidase in terminal leaves are increased, but that of fumaric reductase in root system is decreased.

Nutritional condition of Rushan Bay in spring tidal phase of August

Ma Shaosai, Zhou Shilai, Zhao Jun, Yu Huiting

1996, 7(2):  221-223. 

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The COD, IN and IP of Rushan Bay in spring tidal phase of August, 1994 are used as single and multiple indexes to evaluate its nutritional condition. The results show that the nutritional conditions at the mouth of Bay and the inlets of east and west valleys are better, but are eutrophic at the rest of the Bay. In east and west valleys, COD is 0.61 and 0.93 mg· L^-1, IP is 0.017 and 0.015 mg· L^-1, and iN is 0.212 and 0.369mg· L^-1,respectively.