Table of Content

25 July 1996, Volume 7 Issue 3

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Articles

Regulating strategies to sustainable development of plantation ecosystems

Liao Liping, Chen Chuying, Zhang Jiawu, Deng Shijian

1996, 7(3):  225-229. 

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Based on field and laboratiory experiments,the effect of different management approaches on site fertility and sustainability of plantation ecosystems such as Cunninghamia lanceolata and Pinus massoniana is analysed.The results show that some biopathways such as intercropping with leguminous grass,silviculture of mixed plantations, introducing broadleaved tree species after thinning,and some engineering measures such as application of fertilizers and changing methods of site preparation can be helpful to the recovery of soil fertility and the increase of productivity of pure conifer forest.

Estimation of carbon sink function of forests in China

Kang Huming, Ma Qinyan, Yuan Jiazu

1996, 7(3):  230-234. 

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Estimation of the amount of carbon accumulated by forests in China shows that at present time,the accumulation is higher than the release,and the net absorption is about 86.27 million tons C per year,which will increase by 7.73 million tons per year in the future 20 years and reach to 146.97 million tons by the year 2000.

Physical properties of wood quality of farm shelterbelts

Fan Zhiping, Jiang Fengqi, Lin Heming, Zhu Jiaojun, Zeng Qiyun, Luan Shujie

1996, 7(3):  235-239. 

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Studies on the width and density of ring and the length, shrinkage rate and their radial variations of wood fiber of Salix matsudana and Populus pseudo-simonii show that the physical properties of wood are significantly affected by its ring age,and the fiber length of wood is not influenced by ring width.Through synthesizing the radial variation patterns of wood properties,it is suggested that the whole growth period of these two kinds of tree species can be divided into young growth, fast-growing,mature and regeneration stages.The age value of each stage is defined.

Clonal growth pattern of Pleioblastus maculata clone population

Liu Qing, Zhong Zhangcheng

1996, 7(3):  240-244. 

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By the method of reverse age-class addition(RAA),the dynamics of clonal growth pattern of Pleioblastus maculata clone population on Mt.Jinyun,Chong qing,Sichuan,China is studied. The results show that as a complex axis type,the degree of clump dispersion pattern of this population is gradully decreased with time.In natural habitat,the populaton is mainly reproduced in single axis way.The RAA technique is worthy and reliable for analysing the dynamics of clonal growth pattern of plant population,and bamboo population in particular.

Relationship between rosin output of Pinus densata and air temperature and humidity at Zhamu region of Tibet

Xu Asheng

1996, 7(3):  245-249. 

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The patterns of rosin secretion from Pinus densata at Zhamu region of Tibet are studied under different air temperature and humidity.Regression analysis shows that under appropriate air temperature,relative air humidity is the main factor affecting the daily output of rosin from P.densata.Water supply is of importance to the rosin output.

Variation of drought-enduring characteristics of Pinus sylvestris var.mongolica under different climatical moisture

Zhu Meiyun, Tian Youliang, Guo Liansheng

1996, 7(3):  250-254. 

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The drought-enduring physiological indexes(π_p,ε,etc.)of Pinus sylvestris var.mongolica are measured with 14～16 years old plantations on sandy lands in subhumid semiarid and transitional(from semiarid to arid)regions of inner Mongolia.The results show that thedrought-enduring indexes have a significant regional difference(P≤0.05),which is correlated with local climatic moisture index(I_m),and can be expressed as Y=A+BX (Y,drought-enduring index;X,I_m;and B,variation rate).When I_m is varied from-29.6(Hailar) to -70.2(Huoluo),the variation rate(B)of bulk osmotic potential at initial turgor loss point (π_p) is 0.0034 MPa at early stage of young branch growth and 0. 0061MPa at the last stage of yearly growth period.Similarly,the variation rate(B) of bulk elastic modulus (ε) with I_m is 0.017 and 0.031 MPa,respectively.It is concluded that the drought-enduring property of Pinus sylvestris var. mangolica can be varied and improved by drought trainning.

Parameters of metapopulation dynamics of wild soybean originated from different latitudes and their significance of ecological adaptation

Gao Xinhua, Li Hongyuan, Zheng Shizhang, Zhou Jilun

1996, 7(3):  255-261. 

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Wild,half-wild and cultivated soybeans originated from different latitudes are transplanted to same area and sowed at different time.The results show that the metapopulation dynamics of three kinds of structural units of Glycine soja can all be simulated with logistic model,where parameter r is positively correlated with latitude, and K is affected by environmental modification.The simulation parameter r of metapopulation dynamics is positively correlated with the reproductive capacity of the plant,which substantiates that metapopulation dynamics of plant has an important significance of ecological adaptation.

Effect of root iron plaque on zinc uptake by rice

Zhang Xike, Zhang Fusuo, Mao Daru

1996, 7(3):  262-266. 

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Solution culture is conducted to investigate the effect of root iron plaque on zinc uptake by rice plant. The results show that under anaerobic condition,oxygen release from root to rhizosphere causes the formation of precipitated iron oxides or hydroxides plaque on root surface,which influences the zinc uptake by plant.If less iron plaque is existed the zinc uptake can be enhanced. When the amount of iron plaque were 12100 mg·kg^-1 root DW,the zinc uptake by rice reaches to maximum.However,with increasing amount of iron plaque(more than 12100 mg· kg^-1 root DW),the zinc is inhibited, and the plaque becomes a barrier for zinc uptake. Under Fe deficiency,the exudates of rice root,especially phytosiderophore,play an important role in zinc uptake by rice root with plaque,and the significance of phytosiderophore in zinc uptake is correlated with the amount of iron plaque.If the plaque is less,phytosiderophore appeares to enhance the zinc uptake. With increasing amount of iron plaque, the role of phytosiderophore in mobilizing zinc absorped on plaque becomes less important.Therefore, iron plaque on rice root could be either a beneficial reservoir or a barrier for zinc uptake by rice plant, which depends on the amount of iron plaque.

Effeet of subsoiling on crop yield in semi-arid area of west Liaoning and its mechanism

Wang Shixin, Cui Jianbo, Zhuang Jiping

1996, 7(3):  267-272. 

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The study shows that subsoiling can break up tillage pan,decrease penetration resistance and soil bulk density,increase subsoil porosity,and results in a deeper water infiltration depth,which is up to 80 cm.After subsoiling,the root length of soybean is increased by 3.6～4.0 cm,its yield and water use efficiency are respectively increased by 27.7～34.5% and 16.1%,and in drought year,maize yield is increased by 7.9%.

Impact of soil humidity on N₂O production and emission from a rice-wheat rotation ecosystem

Zheng Xunhua, Wang Mingxing, Wang Yuesi

1996, 7(3):  273-279. 

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Based on the in-situ measurement of soil humidity and N₂O emission from a rice-wheat rotation ecosystem and on the simulated experiment in laboratory,the impact of precipitation and soil humidity on N₂O production and emission is studied.The results show that the N₂O emission from wheat field is positively correlated with precipitation in spring and autumn but not in winter,and that from rice field is not influenced by precipitation.Within a cycle of rice-wheat rotation, N₂O emission is intensively affected by soil humidity.97～100% of soil water holding capacity (i.e.,84～86% of WFPS) leads to a maximum N₂O emission.When the soil humidity is lower than this range,there is a positive correlation between N₂O emission flux and soil humidity, and on the contrary,there is a negative one.The variation pattern of N₂O emission with soil humidity is similar both under field and under simulated condition, although under the former one,the optimum humidity range for N₂O emission is lower.

Structural dynamics of aboveground biomass of communities on Songnen grassland after different burning time

Zhou Daowei, Zhu Ling, Zhang Baotian

1996, 7(3):  280-282. 

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The structure of aboveground biomass of communities on Songnen grassland is changed in yaring degrees after different burning time.On burned plot,the litter is removed;but on unburned one,it is gradually transfered to the lower layer of the community.The stem is dwarfed on burned plot and its leaf biomass is greater;but on unburned plot,the ratio of stem to leaf is higher.The penetration coefficient of light is higher on burned plot than on unburned one.

Structure of saline-alkali tolerant dicotyls on west grassland

Lu Jingmei, Li Jiandong, Zhang Hongqin, Zhou Daowei, Xiao Hongxing

1996, 7(3):  283-286. 

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Scanning electron microscopic studies on the structure of 7 saline-alkali tolerant dicotyls,Suaeda corniculata,Cynanchum chinense,Lappula intermedia, Potentilla supina and Artemisia anethifolia show that their roots have well-developed aerenchyma, and have the structural characters of saline-alkali and drought-tolerant.The subsidiaries on their leaf Surface such as epidermal hair,cuticle and waxy decorative patterns also show the stressreslstant structures.

Use of a xylE marker gene to monitor the survival of rhizobia populations in soil

Cui Mingxue, Zhang Chenggang, Jin Suying, Zhang Xiaodong, Li Mingqi, Li Ning, Lin Jishang

1996, 7(3):  287-292. 

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XylE gene containing plasmid pLV1016 is introduced into Rhizobium fredii QB1130 and Rhizobium leguminosarum bv.viciae B40 by bacterial conjugation,and the expression level of xylE gene in rhizobia is quite high.The use of xyLE gene carried by plasmid pLV1016 to monitor the survival of rhizobia in sterile and non-sterile soils shows that in sterile soil,there is no significant difference(P<0.05) between the survival of strains containing and free of plasmid. Large inoculum quantity is.advantage to the growth and reproduction of bacteria,and the loss rate of plasmid B40(pLV1016):very low.When the inoculation is made with a concentration lower than 10⁶ CFU·g^-1 dry soil,the loss rate of plasmid QB1130(pLV1016) is increased with decreasing inoculation concentration.In non-sterile soil,biotic factors can inhibit the growth of released strains,and large inoculum quantity is advantage to the survival of bacteria. When the inoculation is made with a concentration lower than 10⁶ CFU·g^-1 dry soil, the loss rate of plasmid QB1130(pLV1016)is higher than that of plasmid B40 (PLV1016).

Preliminary study on respiration rate of soil microorganism under different vegetations on Aneurolepidium chinense grassland of northeast China

Zhang Chongbang, Yang Jingchun

1996, 7(3):  293-298. 

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The respiration rate of soil microorganism under different vegetations and its correlation with ecological factors are studied. The results show that the respiration rate is the highest(17.2μlCO₂·g^-1dry soil·h^-1) in A.chinense soil,and lowest(8.7μlCO₂·g^-1dry soil·h^-1) in Cleistogenes squarrosa soil,being decreased with increasing soil depth.The peak is occured in August,being 28.39μlCO₂·g^-1 dry soil·h^-1.Correlation analysis shows that the respiration rate is positively related to plant biomass and soil conditions(e.g.,moisture-hear regime and nutrient status),and negatively related to soil PH.

Analysis on landscape fragment of Liaohe delta wetlands

Wang Xianli, Bu Rencang, Hu Yuanman, Xiao Duning

1996, 7(3):  299-304. 

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In this paper,the wetland landscape of Liaohe delta is studied with remote sensing and GIS and six approaches are used to analyze its fragmentation.The results show that this area is lightly fragmented,the patch density of landcapes is 0.286 individual·km^-2,the corridor density is 1.098 km·km^-2 and the aggregation index of various landscapes is 0.955.Landscape fragmentation is closely related to human activites,and the fragmentation level is increased with increasing human activities on the landscapes.The expansion of corridors is the premise and impetus of landscape fragmentation.

Community ecology of intertidal zone of Shengsi archipelagoⅠ.Species constitution and seasonal variation of benthic biocommunity in rocky intertidal zone

Yang Wanxi, Chen Yongshou

1996, 7(3):  305-309. 

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Studies on the benthic biocommunity in rocky intertidal zone of Shengsi archipelago show that under the influence of salt concentration and seashore spacious degree,there exist three kinds of biocommunities,i.e.,low,broad-and high-salt ones.The number of polychaetes shows an increasing trend from west to east.The density and biomass of molluscs are in the order of SS₄>HL₃ >SJ₂ >DY₁ and DY₁ >SJ₂> HL₃ >SS₄,and those of crustaceans are DY₁ >SJ₂> HL₃ >SS₄ and SS₄>HL₃ >SJ₂ >DY₁,respectively.The biomass of algae is all HL₃>SS₄>SJ₂>SY₁,and the number of polychaetes is in the order of midtide area >low-tide area>high-tide area at DY₁ and SJ₂, and of low-tide area>mid-tide area>high-tide area at HL₃ and SS₄.The biomass of molluscs,crustaceans and algae is all in the order of mid-tide area>low tide area >high-tide area.Algae biomass is the highest in spring and autumn, but lower in summer.The biomass of benthic invertebrates at sampling section DY₁ is higher in summer and autumn, but becomes lowest in winter.At SJ₂ and HL₃,it is maximum in spring and autumn,and at SJ₂ and HL₃,it is minimum in winter and spring.

PCA analysis on sulphur and heavy metals contents in different parts of woody species in Chengde of North China

Jiang Gaoming

1996, 7(3):  310-314. 

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Principal component analysis(PCA) and ordination analysis(OA)on sulphur and heavy metal contents of 10 woody species in Chengde show that components Z₁ and Z₂ can mainly represent most of information reflected by 7 elements analysed,with an accumulative rate of >98%.Sulphur has a largest contribution to Z₁,while Fe,Zn,Mn and Pb have a stronger influence to Z₂.It is indicated that in the urban area of Chengde,sulphur pollution is most remarkable.Among heavy metals,Zn,Fe,Mn and Ph are serious pollutants, while Cu and Ni are not.In different parts of woody species,bark is most seriously polluted,twig is the second,and leaf is the lowest.

Quantitative characteristics of translocation of petro-alkane in environment

Li Shuding, Zhang Shaolan, Ma Jichun

1996, 7(3):  315-320. 

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The translocation,accumulation and distribution of petro-alkane in soil-rice system are studied with ¹⁴C-hexadecane tracer technique.The results show that when the deposition amount of mineral oil in soil arrives at 180 mg·kg^-1,rice plant will be withered. But,it can grow normally if the soil is mixed with 300 mg·kg^-1 of mineral oil before its transplanting.In meadow brown soil planted with rice,the distribution coefficient(Kd)of hexadecane is 216, and its distribution in soil-rice system is rice>water>soil.The residual amount of hexadecane is decreased with the order of water> soil>rice.In rice growing period,the loss amount of mineral oil occupies 39% of the total.At oil-polluted area,the annual amount of mineral oil carried-out by runoff occupies 58% of its total loss.

Expert system design for agroecological patterns of multiple cropping in Lower Reaches of Liaohe PlainⅠ.Design thought of the system

Liang Wenju, Wen Dazhong, Shen Shanmin, D. D. Calvin, M. C. Saunders, E. G. Rajotte, J. E. McClure, Zheng Binglin, Liu Fuxiang

1996, 7(3):  321-325. 

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In this paper the practice of agroecological patterns of multiple cropping in the Lower Reaches of Liaohe Plain is described.The design thought of an expert system of agroecological patterns of multiple cropping is put forward by applying the principles of agroecology,and the design principles for overall structure of the system is described with the integrated approach of expert system(ES),geographic information system(GIS)and relational database management system(RDBMS).A new approach to the management of regional agroecosystems is theoretically explored by means of high and new technology of computer.

Incidental catch and its impact on marine mammal populations

Yang Guang, Zhou Kaiya

1996, 7(3):  326-331. 

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Incidental catch of marine mammals is almost occured all over the world.62 species belonging to 14 families of Cetacea,12 species belonging to 3 families of Pinnepedia,2 species belonging to 2 families of Serenia and I species belonging to 1 families of Carnivora are caught incidentally.The fishing gears involved in the incidental catch include gill net,trawl net, surrounding net,stow net and traps,etc.Incidental catch can cause the decline of population number and the change of its life history.A survey on the incidental catch and its impact on the mammal population in Chinese waters should be conducted.

Study on the structure and function of major ecosystems in China in relation to the approach of increasing productivity──A brief introduction to the research progress of the project KJ 85-06 in 1991～1995

Shen Shanmin

1996, 7(3):  332-336. 

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The KJ 85-06 was the largest ecology research project financed by the Chinese Academy of Sciences in the eighth five-year plan. Nineteen research institutions,twenty research stations and some five hundred researchers were involved in the project.The total budget of the project was ten million Chinese yuan in 1991～1995.Great progress was achieved,some four hundred and fifty papers and three monographs were published thus far,and more will be published in coming years. In this paper,some of the new findings are briefly discussed,and suggestions regarding to the research of optimum management of ecosystems and the network research of ecological process and the impact of human activities are made.