Table of Content

15 January 2002, Volume 13 Issue 1

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Natural regeneration of Pinus sylvestris var mongolica plantation on sandy land

ZENG Dehui, YOU Wenzhong, FAN Zhiping, LIU Mingguo

2002, (1):  1-5. 

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By employing comparison analysis and field survey, the natural regeneration of Mongolian pine plantations on sandy soil was investigated. In plantation areas where regeneration can take place naturally, natural regeneration of Mongolian pine varied temporally and spatially. Natural regeneration wasn't temporally continuous; it had a close relationship with autumn precipitation in particular years. In spatial aspect, there were three regeneration types: regeneration in forest gaps, regeneration on edges of a forest, regeneration under young broadleaf forest. There was no significant difference between the growth of regeneration saplings and plantation trees.

Skewness and inequality of height distribution of young Pinus sylvestris varmongolica stands introduced on sandy soil with lower limited precipitation for tree survival and normal growth

ZHAO Wenzhi, LIU Zhimin, CHANG Xueli

2002, (1):  6-10. 

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Based on the investigation of a transect (20m wide and 80 m long) along a gradient (bottom,middle,and top) of a dune,whose height was about 5～10m,the population dynamics in young Pinus sylvestis var.mongolica stands was studied.The results showed that both skewness and height inequality declined before the self-thinning process occurred.Age,initial growth status,density of the population,and neighborhood competition were the main factors affected height inequality.The location at sand dune was also an important factor,and its effect was more obvious than that of density.

Study on thinning to Robinia pseudoacacia forest on the Loess Plateau

WANG Keqin, WANG Binrui

2002, (1):  11-15. 

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Radiation, temperature and soil moisture in the forests, the biodiversity and productivity of understory plants, and the growth of trees among3 thinned 9-year-old Robinia pseudoacacia forests (735 individuals穐m^-2 ,1110 individuals穐m^-2 , and 1480 individuals穐m^-2 ) and non-thinning forest (2220 individuals穐m^-2 ) were analyzed comparatively. The results showed that thinning could improve growing condition of trees and understory plants, so that the biodiversity and biomass of understory plants and producing ability of trees were increased. When the remaining density was 1110 individuals穐m^-2 , the soil moisture was increased by 40% comparing with the non-thinning forest in whole growing seasons. The biodiversity and biomass of understory plants and productivity of trees were increased significantly. If the thinning intensity were increased continuously, the growth of understory plants and trees would reach the maximum and not increase any longer. Therefore, the thinning intensity with remaining density of 1110 individuals穐m^-2 was optimum for black locust forest in this region.

Change of component structure of shrubland in Tiantong region,Zhejiang Province under different treatments

ZHANG Guangfu, SONG Yongchang

2002, (1):  16-20. 

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The community diversity of shrubland in Tiantong region,Zhejiang Province was measured by using the methods of species of abundance,Simpson index,Shannon-Wiener index and community evenness index.The beta diversity between before treatments and after treatments was also measured by applying β diversity index and similarity index.In addition,the changes of species composition and their importance values in the shrubland were analyzed.The results showed that whether in the first or second group of plots,the species composition and their importance values changed in varying degree.Compared with plots before treatments,the species diversity of shrub layer of experimented plots decreased while ecological dominance and community evenness were improved.By means of comparing beta diversity and similarity index,the results also showed that the species composition of experimented plots have changed to various extent.

Age structure and dynamics of Keteleeria davidiana varchien-peii population in Guizhou Province

LIANG Shich, LI Jiulin, CHENG Shize

2002, (1):  21-26. 

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Type and dynamics of age structure of Keteleeria davidiana var.chien-peii population and its relationship to community succession and environment were analyzed.The results showed that the age structures were classified into four types:growing,stable,inital and middle sensecent types.The survival curves had concave,convex,disconnected and dotted shapes.Along with development and succession of community,the age structure changes from growing,stabilized,senescent to residual type.The important factors causing change to the age structure were biological features of Keteleeria davidiana var.chien-peii,development of broad-leaved tree species,geographic isolation,and human disturbance.

Comparison of leaf decomposing rate in a headwater stream in Xiangxi River catchment

JIANG Mingxi, DENG Hongbing, TANG Tao, CAI Qinghua

2002, (1):  27-30. 

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With the litterbag method,the decomposition of leaf of 4 tree species growing in riparian forest in a headwater stream was inestigated in90 d consecutively in Xangxi River catchment.The results showed that the loss rate of dry weight of leaf differed among4 species.The loss rate of dry weight of Pterocarya insignis and Cercidiphyllum japonicum was 77% and 71%,and shat of Fagus engleriana and Cyclobalanopsis multinervis was 43% and 42%.Using exponential equation,the loss process of dry weight of leaf was modeled.According to the value of constant k,4 species could be divide into to fast group and medium group.The invertebrate was also collected,and there were 22 species,belong to 3 classes,6 orders,and 21 families.The quantity of invertebrate differed in each tree species litterbag and different periods.The invertebrate was rich in number and small in body during early time of leaf decomposing,and it was less in number and big in body during middle and late time of decomposing.

Assistant assessment of landscape indices for general planning program of Wusuli River National Forest Park

ZHONG Linsheng, XIAO Duning, CHEN Wenbo

2002, (1):  31-34. 

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Landscape indices provide quantitative information about landscape pattern and predict some ecological processes.Rationality of Wusuli River National Forest Park' general planning program was evaluated by comparatively analyzing the landscape indices change.The results indicated that the number of patch decreased from 413 to 401,Shannon's evenness index increased from 0.755 to 0.787,and predominant index decreased from 25.547 to 24.500.In addition,the network connectivity index,the network circuitry index,and landscape attractive power between scenic spot were increased,and the extent of landscape fragmentation was decreased.So,the planning would improve the landscape pattern,enhance ecosystem stability and landscape quality,and be useful for ecological protection and ecotourism development.

Analysis on forest plant diversity in the Three Gorges Reservoir Area

CHENG Ruimei, XIAO Wenfa, LI Jianwen, MA Juan, HAN Jingjun

2002, (1):  35-40. 

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The forest resource is rich in the Three Gorges Reservoir Area, according to the investigation data in the area, there are 41 kinds of forest communities, and the trend of the richness index, species diversity index and evenness index is not regular. In the coniferous forest, the trend of the richness index in different layer along the community is shrub >herb>tree. In the evergreen broadleaf forest, the trend is shrub > tree > herb. In the deciduous broadleaf forest, especially the typical Quercus forest, the trend is shrub >herb and tree, but in the herb layer and the tree layer, the trend fluctuates. The trend of the species diversity index is tree < herb and shrub, but in the herb layer and the shrub layer, the trend fluctuates. In other communities, the trend of all indices along the community fluctuates too. One reason may be the different natural environment and different growth condition of the community, and the long time strong disturbance of the human population is another important factor that couldn't be ignored.

Photosynthetic characteristics of three tree species seedlings in Changbai Mountain under different CO₂ concentrations

ZHOU Yumei, HAN Shijie, ZHANG Junhui, ZOU Chunjing, WANG Chenrui, CHEN Yongliang

2002, (1):  41-44. 

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The photosynthetic characteristics of three-year-old seedlings of coniferous Pinus koraiensis and Pinus sylvestriformis and broadleaf Fraxinus mandshurica in open-top chambers in Changbai Mountain were studied.Seedlings were planted at four different conditions respectively:elevated CO₂ concentration(700 and 500 μmol·mol^-1)and ambient CO₂ concentration (control chamber and in open field).After treating of two growing seasons in the first two years,seedlings were continuously grown under different CO₂ concentration for another eight weeks.The results indicated that the photosynthetic capacity of three species was enhanced under high CO₂ concentration in the first two growing seasons.The maximum net photosynthetic rates and light response parameters of different tree species were different at the same CO₂ concentration.No photosynthetic acclimation was observed in the third growing season except Pinus sylvestriformis seedlings grown under 500 μmol·mol^-1 CO₂.The increase or decrease of net photosynthetic rates and light response parameters were related to the time of CO₂ treatment.Elevated CO₂ concentration could alter the ability of utilizing strong light and low light of seedlings.

Ecological adaptability of Pennisetum centrasiaticum clones on farmland-sand dune ecotone of Keerqin sandy land

CHEN Shiping, GAO Yubao, REN Anzhi, LIANG Yu, LIU Shuang, LIU Ning

2002, (1):  45-49. 

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The individual growth,morphology and population biomass of Pennisetum centrasiaticum clones at two different habitats of farmland-sand dune ecotone on Keerqin sandy land of Inner Mongolia were compared in this study.P. centrasiaticum clones had significant morphological plasticity and different biomass distribution pattern at different habitats.Compared with P. centrasiaticum clones on semi-fixed sand dunes,those on farmland-sand dune transitive zone had a greater leaf elongation,longer rhizomes and internodes,more adventitious buds,larger amount of biomass,and deeper distribution of underground biomass,which were closely associated with the losse texture of the upper soil and the rather favorable water condition of the lower soil.It is believed that the population can well adapt itself to the farmland-sand dune ecotone habitats,and thus,play an important role in fixing mobile sand in succession of arenaceous vegetation.

Analysis on competition and coexistence patterns of Aneurolepidium chinense and its main companion species

BA Lei, WANG Deli, LIU Ying, WANG Xu, SUN Wei

2002, (1):  50-54. 

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In this study,transects were set in areas where Aneurolepidium chinense and its companion species grew together.Competition and coexistence patterns of these species in the ecotone were analyzed using the following measures:frequency distribution,spatial pattern,and pattern intensity.Patterns of A. chinense and its main companion species were diverse.Aggregation was the tactics for A. chinense to defend the foreign species' invading or disperse itself.There existed competition and coexistence between A. chinense and its main companion species.A. chinense and Phragmite communis competed and coexisted through suppression.A. chinense and Kalimeris interifolia coexisted through competition.Hierochloe glabra and Puccinellia tenuiflora competed with A. chinense through clonal growth.Calamagrostis epigeios was suppressed by A. chinense.

Population physiological indices on density-tolerance of maize in different plant type

XUE Jiquan, LIANG Zongsou, MA Guosheng, LU Haidong, REN Jianhong

2002, (1):  55-59. 

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Taken maize in two plant types of compact-type and flat-type as research object,the relationships between density-tolerance and light distribution in population,indices of productivity(LAI,NAR,and CGR),and population sink-source were studied synthetically by means of crop growth analysis method.The results showed that light distribution in population was the chief index to measure density-tolerance of different maize varieties.The kinetic rules of LAI,NAR,and CGRwere the basic feature reflecting density-tolerance.The correspondent relationship in population sink-source was a comprehensive index to appraise density-tolerance of different maize varieties.

Root growth in rice and its response to soil density

ZHU Defeng, LIN Xianqing, CAO Weixing

2002, (1):  60-62. 

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Studies on root growth and vertical distribution at tillering(TL),panicle initiation(PI),flowering(FL) and mature(MT) stages and effects of soil compaction on root growth were carried out with hybrid rice of Shanyou 63 and 65002 in root box.The results indicated that root weight reached maximum at flowering stage and then decreased.With the advance of growth stage,percentage of deep roots(20～45cm in soil) increased.Root weight increased at highest rate and deep roots formed during the period of TLto PI.With increased soil weight density below 20 cm,root weight and percentage of deep roots markedly decreased.

Effect of fertilization on the qualities of sweet pepper in greenhouse culture

SUI Fanggong, WANG Yunhua, Makoto Nagatomo, Naoya Chishaki, Wunimuren, Shunji Inanagea

2002, (1):  63-66. 

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In order to study the effect of fertilization on the qualities of sweet pepper(Capsicum annul L)cultured in greenhouse,the experiment was carried out by drop irrigation.The results showed that the most sensitive organ of sweet pepper for nitrate was lateral branch,in which the nitrate content was highest.The nitrate content in leaf was lower than that in lateral branch,and in fruit,the nirtate content was the lowest.High fertilization of N,Pand Khad no negative influence on content of nitrate and total soluble sugars in fruit.The content of soluble sugars in fruit were about 50%～55% under all treatment and higher than that in leaf and lateral branch.Decreasing fertilization would cause increasing of the inosital and sucrose contents.Glucose and fructose were the main soluble sugars in fruit.The metabolism of carbohydrates was weakened by high fertilization,and it experessed as restraining the accumulation of starch content in leaf.The content of starch was the highest in fruit.The lipid content were exceed 3～4 times in the leaf than in the lateral branch and fruit,and perhaps,it was due to the hiher content of chlorophyll in the leaf.

Effects of precipitation and soil moisture on N₂O emissions from upland soils in Guizhou

XU Wenbin, LIU Guangshen, LIU Weibing

2002, (1):  67-70. 

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Soils of corn-rape seed rotation,soybean-winter wheat rotation and fallow land in Guizhou were representatively selected to study effects of precipitation and soil moisture on N₂O emissions.Furthermore,DNDC model was used to assess the potential effects of variations in precipitation in future on N₂O emissions from above lands.The results indicated that N₂O emission pulses were obviously driven by rainfall and N₂O fluxes were correlated positively with precipitation and soil moisture.The results from DNDCmodeling showed that N₂O fluxes from soils in summer and autumn would be correlated positively with precipitation,but N₂O fluxes in winter and spring would slightly decrease with great change of precipitation.

Study on the ecological regions of soybean in China Ⅱ Ecological environment and representative varieties

WANG Yusheng, GAI Junyi

2002, (1):  71-75. 

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Based on the climatic and geographical condition,cropping system and season sowing types and maturity group (MG) types of 256 varieties in test from total cultivating regions of soybean in China,six ecological regions of soybean were suggested.Those are:Northern single coropping,spring planting eco-region(Ⅰ),Huanghuaihai double cropping,spring and summer planting eco-region(Ⅱ),Middle and lower Changjiang valley double corpping,spring and summer planting eco-region(Ⅲ),Central south multiple cropping,spring,summer and autumn planting eco-region(Ⅳ),Southwest plateau double cropping,spring and summer planting eco-region(Ⅴ),and South China tropical multiple cropping,all season planting eco-region(Ⅵ).The cultivating environmental condition and representative varieties were shown,and the characteristics of all ecological regions of soybean in China were also discussed in this paper.

Allelopathy of Ageratum conyzoides ⅥEffects of meteorological conditions on allelopathy of Ageratum conyzoides

HU Fei, KONG Chuihua

2002, (1):  76-80. 

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In the field,allelopathic potential of A.conyzoides correlated significantly with sunshine time,temperature and rainfall.Allelopathic potential of A.conyzoides grew in favorable combinate condition of temperature,rainfall and sunshine time,allelopathic potential of A.conyzoides reduced,and vice versa.Allelopathic potential of A.conyzoides decreased because of favorable growing seasons in spring and summer.On the contrary,autumn and winter were unfavorable growing seasons,and the allelopathic potential of A. conyzoides increased.Under laboratory experiments,the volatile oil of A.conyzoides made the tested plants not survive at high concentrations of 300 μg·ml^-1 ,but volatile oil of A.conyzoides inhibited the tested plants slightly at low concentrations of 60 μg·ml^-1.However,under high or low temperatures and shading conditions,inhibitory effects of allelochemicals of A.conyzoides on tested plants intensified significantly at low concentration.It revealed that under unfavorable growing conditions,tested plants resistant ability to the allelochemicals of A.conyzoides decreased.When A.conyzoides and tested plants both grew under unfavorable meteorological conditions,allelopathic potential of A.conyzoides increased,and the tested plants resistant ability to allelochemical decreased.Thus,other plants growing among A.conyzoides in natural community were difficult to grow,and it was relatively improved competitive ability of A.conyzoides in natural communities.Joint effect of allelopathic potential and some meteorological factors such as sunshine time,temperatures,and rainfall was one of the important factors that A.conyzoides was dominated in natural communities.

Landscape pattern analysis based on boundary characteristics

ZENG Hui, KONG Ningning

2002, (1):  81-86. 

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Through boundary number to the length distribution spectrum analysis,the relationships between boundary number-length and fragmentation of landscape and element were discussed.Landscape pattern indices such as diversity,evenness,heterogeneity,and spatial complicity were calculated based on boundary number and cumulative length,and these indices were compared with those based on element area proportion.The results indicated that the fast urbanization process caused complication of boundary element distribution pattern and simplification of layer structure.The distribution function parameter α could reflect landscape fragmentation properly,and the landscape pattern indices based on boundary characteristics was an useful supplement for traditional pattern analysis.

Effects of different mycorrhizal fungi on physiological metabolism of tobacco seedlings

WANG Yuanzhen, KE Yuqin, PAN Tingguo

2002, (1):  87-90. 

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Tobacco seedlings were inoculated with VAmycorrhizal fungi in natural soil.The results showed that compared with the control,the contents of nitrogen,phosphorus,potassium and chlorophyll,nitrate reductase activity,and protein in leaves were higher,malondialdehyde(MDA) and hydrogen peroxide(H₂O₂) decreased,while the activities of superoxide dismutase(SOD),catalase(CAT),and peroxidase(POD) increased.Meanwhile,seedlings were inoculated with two strains of ectomycorrhizal fungi respectively,and the above physiological indices trended the same changes.Moreover,the effect of strain Calvatia lilacina was higher than that of VAmycorrhizal fungi.

CCA of water beetles' distribution and environmental factors in lentic samples of North Changbai Mountain

WE Yulian, JI Lanzhu, WANG Miao, ZHAO Min

2002, (1):  91-94. 

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The relationship between 28 species water beetles in 12 lentic samples and environmental factors of North Changbai Mountain was studied by Cononical Correspondence Analysis (CCA).The results showed that degree of underwater humus and altitude are the major factors correlated with beetles distribution,and the correlation coefficients of envirommental factors and axes of CCAwere 0.8371 and 0.7206 respectively,while water temperature and plant density also had certain effects.Under the influence of environmental factors,the water beetles' populations were different in different habitat.Coelambus impressopunctatus,Colymbetes magnus,Helophorus browni,Haliplus spp.distributed in deep water pool.Water temperature was not important for those beetles.Ilybius sp.and Limnebius glabriventris correlated with altitude and humus.

Main factors influencing the growth of planktonic bacteria in fish pond ecosystem

TAN Hongxin, HU Yuang, MEI Zhiping

2002, (1):  95-100. 

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Focused on the main factors influencing the growth of bacteria in fish pond ecosystem, the variation of abundance in bacterial culture, the effects of substrate on bacterial growth, nutrient uptake and mineralization, the effects of bacterivorous predator and water temperature on bacterial growth were investigated in this paper. The results showed that the growth of bacteria and its uptake of Cand Nwere enhanced by application of inorganic phosphorus into the water, but not by application of organic carbon and nitrogen, and that the Nmineralization was increased by adding organic nitrogen, indicating that the bacterial growth was limited by inorganic Pin the substrate, not by organic Cand N. Among the five test groups,predator bacteria had the slowest growth rate,being lower than the control by 626～154%. The abundance of bacteria,its number increment and growth rate in the fish pond were found to be positively correlated with water temperature in different seasons.In addition,at higher temperature,the positive effects of nutrient application on bacterial growth were enhanced,while the negative effects of predator bacteria on bacterial growth were weakened.

Insecticide resistance of different populations of white-backed planthopper,Sogatella furcifera(Horv醫h)(Homoptera:Delphacidae)

YAO Hongwei, JIANG Caiying, YE Gongyin, CHENG Jiaan

2002, (1):  101-105. 

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Resistance to some insecticides used commonly in different populations of the white-backed planthopper,Sogatella furcifera collected from Zhejiang,Guangxi,Yunnan and Hainan Province in China was measured.The specific activities of some resistance-associated enzymes,i.e.esterase,carboxylesterase,glutathione S-transferase and acetylcholinesterase from these populations were also measured.The resistant levels to malathion,methamidophos,isoprocarb and buprofezin were markedly higher in Yunnan and Hainan populations than in other populations,but considerably more heterogeneity in response to insecticides was found in Zhejiang and Guangxi populations.The specific activities of the enzymes were obviously higher in Zhejiang and Guangxi populations than in Yunnan and Hainan populations,and the distribution range of the enzyme activity was the widest in Zhejiang population,and the narrowest in Guangxi population.Finally,The relationship between the long-distance migration and the territorial difference in insecticide resistant level and activityes of the enzymes in the populations of this planthopper was discussed.

Fluoride accumulation and distribution in mulberry insects near fluoride pollution sources

CHEN Yuyin, LU Shenggao

2002, (1):  106-108. 

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Fluoride accumulation and the relative fluoride loading of different body parts in wild mulberry silkworm (Bombyx mandarina M.), mulberry geometrid (Pathonandria atrineata B.), and mulberry silkworm (Bombyx mori L.) near fluoride pollution sources were studied. Comparison of the fluoride content of insect bodies and mulberry leaves showed that insects collected from polluted sites had increased fluoride accumulation. The digestive tract of the insect had much higher fluoride content than the other parts of the body and was considered to be the important organ of fluoride accumulation. There were also wide differences in fluoride accumulation between different insect species within the same polluted site. The highly significantly correlation between fluoride contents of wild mulberry silkworm, mulberry geometrid, and mulberry silkworm with that of the mulberry leaves on which they were collected was found.

Effects of organic acids on the toxicity of cadmium during ryegrass growth

LIAO Min, HUANG Changyong

2002, (1):  109-112. 

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Effects of low molecular weight organic acids(oxalic acid,citric acid,and acetic acid) and higher molecular weight organic acid(humic acid) on the toxicity of Cd during ryegrass growth were studied.The results showed that Cd toxicity enhanced gradually with increasing the concentration of low molecular weight organic acids,and led to the decreasing of chlorophyll concentration in ryegrass plant and the biomass of ryegrass.The sequence of this influence was:oxalic acid<acetic acid<citric acid.On the contrary,Cd toxicity was reduced as a result of addition of humic acid,and the concentration of chlorophyll in ryegrass shoots and the biomass of ryegrass increased consequently.The concentration of Cd in roots and shoots of the ryegrass increased with increasing the concentration of low molecular weight organic acids,and the sequence of this influence was:citric acid>acetic acid>oxalic acids.The concentration of Cd decreased gradually as a result of increasing the concentration of humic acid,which means humic acid could reduce the toxicity of Cd on ryegrass.Furthermore,the concentration of Cd was higher in roots than in shoots,which indicated that the roots of ryegrass could prevent transport of Cd from roots to shoots and reduce Cd accumulation in the shoots.

Treatment effect of constructed wetlands on organic matter in wastewater from pig farm

LIAO Xindi, LUO Shiming

2002, (1):  113-117. 

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Using plant species Vetiveria zizanioides and Cyperus alternifolius respectively,two constructed wetlands (CWS) with size of 1.0m×0.5m×0.8m were established.The purifying function and its change pattern with season,influent concentration and hydraulic retention time (HRT) of the constructed wetlands on the organic matters in wastewater from a pig farm were studied throughout four seasons in the year.The results showed that the two CWShad very stable effects on the removal of CODand BOD,while the organic matters in wastewater changed.The removal rate of CODand BODwas 70% and 80% respectively by HRT 1～2 d in spring.The removal rate of CODreached 90% with the influent of COD 1000～1400mg·L^-1 in summer.The removal rate of CODand BODwas 50～60% and 50% respectively by HRT 1～2 d in autumn.The removal rate of CODreached 70% with the influent of COD 1003mg·L^-1 in winter.There was no significant difference between two CWSin the removal of COD,BODand SS.The rule of contaminants decreased with the HRTin CWSfollowed exponential function:Y_t=Y₀exp(-kt).The relation between the concentration of contaminants in influent (x) and outflow (y) at the same HRTfollowed linear relation:y=a+bx.

pH of the gill micro-environment of Cyprinus carpio and its effect on the desorption of adsorbed Cu

LONG Aimin, TAO Shu, LIU Changfa

2002, (1):  118-120. 

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pHand CO₂ content differences between fish(Cyprinus carpio) gills micro-environment and the ambient environment were investigated using the technique developed by Playle.The effect of the pHchange on elutriation of copper sorbed on gibbsite was also studied in view of possible desorption of the metal within the gill micro-environment.It was found that there was no pHdifference around pH8.0 and 0.2～0.4 unit difference was observed between the gills' inspired and the expired water when the ambient pHvaried from 8 up to 9.5 or from 8 down to 7.0.Similar trend was detected for CO₂.More Cu adsorbed on the gibbsite can be removed by the acidified expired water from the fish gill micro-environment,comparing to the inspired water.

Classification,application,and creation of landscape indices

CHEN Wenbo, XIAO Duning, LI Xuzhen

2002, (1):  121-125. 

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In landscape ecology,it is very important to understand and grasp the ecological principles of landscape transformation.One of the research methods in common use is to describe landscape pattern and its transformation,and then connect landscape pattern with process by means of landscape indices.Based on the previous studies on landscape indices,some researches on the landscape indices' classification,descriptive ability,relationship among indices and indices' creation were conducted in this paper.Moreover,the general principles of applying landscape indices from two different levels,namely,from single index level and from index system level,were put forward.

Effects of nitrogen and calcium on polyphenol oxidase, peroxidase and leaf spot in carnation

WEI Shenglin, LIU Yehao, QU Haiyong, CAO Jun, YE Hui

2002, (1):  126-127. 

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Carnation inoculated with leaf spot was cultivated under different concentration of nitrogen and calcium in this experiment. The result showed that the nutrition state [NO^-3(0.024%～0.025%),Ca²⁺ (0.022%～0.0342%)] was helpful to keep higher activity of POD and PPOand enhance the carnation's resistance to the germs.

Natural regeneration of Pinus sylvestris var mongolica plantation on sandy land

ZENG Dehui, YOU Wenzhong, FAN Zhiping, LIU Mingguo

2002, (1):  1-5. 

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By employing comparison analysis and field survey, the natural regeneration of Mongolian pine plantations on sandy soil was investigated. In plantation areas where regeneration can take place naturally, natural regeneration of Mongolian pine varied temporally and spatially. Natural regeneration wasn't temporally continuous; it had a close relationship with autumn precipitation in particular years. In spatial aspect, there were three regeneration types: regeneration in forest gaps, regeneration on edges of a forest, regeneration under young broadleaf forest. There was no significant difference between the growth of regeneration saplings and plantation trees.

Skewness and inequality of height distribution of young Pinus sylvestris varmongolica stands introduced on sandy soil with lower limited precipitation for tree survival and normal growth

ZHAO Wenzhi, LIU Zhimin, CHANG Xueli

2002, (1):  6-10. 

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Based on the investigation of a transect (20m wide and 80 m long) along a gradient (bottom,middle,and top) of a dune,whose height was about 5～10m,the population dynamics in young Pinus sylvestis var.mongolica stands was studied.The results showed that both skewness and height inequality declined before the self-thinning process occurred.Age,initial growth status,density of the population,and neighborhood competition were the main factors affected height inequality.The location at sand dune was also an important factor,and its effect was more obvious than that of density.

Study on thinning to Robinia pseudoacacia forest on the Loess Plateau

WANG Keqin, WANG Binrui

2002, (1):  11-15. 

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Radiation, temperature and soil moisture in the forests, the biodiversity and productivity of understory plants, and the growth of trees among3 thinned 9-year-old Robinia pseudoacacia forests (735 individuals穐m^-2 ,1110 individuals穐m^-2 , and 1480 individuals穐m^-2 ) and non-thinning forest (2220 individuals穐m^-2 ) were analyzed comparatively. The results showed that thinning could improve growing condition of trees and understory plants, so that the biodiversity and biomass of understory plants and producing ability of trees were increased. When the remaining density was 1110 individuals穐m^-2 , the soil moisture was increased by 40% comparing with the non-thinning forest in whole growing seasons. The biodiversity and biomass of understory plants and productivity of trees were increased significantly. If the thinning intensity were increased continuously, the growth of understory plants and trees would reach the maximum and not increase any longer. Therefore, the thinning intensity with remaining density of 1110 individuals穐m^-2 was optimum for black locust forest in this region.

Change of component structure of shrubland in Tiantong region,Zhejiang Province under different treatments

ZHANG Guangfu, SONG Yongchang

2002, (1):  16-20. 

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The community diversity of shrubland in Tiantong region,Zhejiang Province was measured by using the methods of species of abundance,Simpson index,Shannon-Wiener index and community evenness index.The beta diversity between before treatments and after treatments was also measured by applying β diversity index and similarity index.In addition,the changes of species composition and their importance values in the shrubland were analyzed.The results showed that whether in the first or second group of plots,the species composition and their importance values changed in varying degree.Compared with plots before treatments,the species diversity of shrub layer of experimented plots decreased while ecological dominance and community evenness were improved.By means of comparing beta diversity and similarity index,the results also showed that the species composition of experimented plots have changed to various extent.

Age structure and dynamics of Keteleeria davidiana varchien-peii population in Guizhou Province

LIANG Shich, LI Jiulin, CHENG Shize

2002, (1):  21-26. 

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Type and dynamics of age structure of Keteleeria davidiana var.chien-peii population and its relationship to community succession and environment were analyzed.The results showed that the age structures were classified into four types:growing,stable,inital and middle sensecent types.The survival curves had concave,convex,disconnected and dotted shapes.Along with development and succession of community,the age structure changes from growing,stabilized,senescent to residual type.The important factors causing change to the age structure were biological features of Keteleeria davidiana var.chien-peii,development of broad-leaved tree species,geographic isolation,and human disturbance.

Comparison of leaf decomposing rate in a headwater stream in Xiangxi River catchment

JIANG Mingxi, DENG Hongbing, TANG Tao, CAI Qinghua

2002, (1):  27-30. 

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With the litterbag method,the decomposition of leaf of 4 tree species growing in riparian forest in a headwater stream was inestigated in90 d consecutively in Xangxi River catchment.The results showed that the loss rate of dry weight of leaf differed among4 species.The loss rate of dry weight of Pterocarya insignis and Cercidiphyllum japonicum was 77% and 71%,and shat of Fagus engleriana and Cyclobalanopsis multinervis was 43% and 42%.Using exponential equation,the loss process of dry weight of leaf was modeled.According to the value of constant k,4 species could be divide into to fast group and medium group.The invertebrate was also collected,and there were 22 species,belong to 3 classes,6 orders,and 21 families.The quantity of invertebrate differed in each tree species litterbag and different periods.The invertebrate was rich in number and small in body during early time of leaf decomposing,and it was less in number and big in body during middle and late time of decomposing.

Assistant assessment of landscape indices for general planning program of Wusuli River National Forest Park

ZHONG Linsheng, XIAO Duning, CHEN Wenbo

2002, (1):  31-34. 

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Landscape indices provide quantitative information about landscape pattern and predict some ecological processes.Rationality of Wusuli River National Forest Park' general planning program was evaluated by comparatively analyzing the landscape indices change.The results indicated that the number of patch decreased from 413 to 401,Shannon's evenness index increased from 0.755 to 0.787,and predominant index decreased from 25.547 to 24.500.In addition,the network connectivity index,the network circuitry index,and landscape attractive power between scenic spot were increased,and the extent of landscape fragmentation was decreased.So,the planning would improve the landscape pattern,enhance ecosystem stability and landscape quality,and be useful for ecological protection and ecotourism development.

Analysis on forest plant diversity in the Three Gorges Reservoir Area

CHENG Ruimei, XIAO Wenfa, LI Jianwen, MA Juan, HAN Jingjun

2002, (1):  35-40. 

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The forest resource is rich in the Three Gorges Reservoir Area, according to the investigation data in the area, there are 41 kinds of forest communities, and the trend of the richness index, species diversity index and evenness index is not regular. In the coniferous forest, the trend of the richness index in different layer along the community is shrub >herb>tree. In the evergreen broadleaf forest, the trend is shrub > tree > herb. In the deciduous broadleaf forest, especially the typical Quercus forest, the trend is shrub >herb and tree, but in the herb layer and the tree layer, the trend fluctuates. The trend of the species diversity index is tree < herb and shrub, but in the herb layer and the shrub layer, the trend fluctuates. In other communities, the trend of all indices along the community fluctuates too. One reason may be the different natural environment and different growth condition of the community, and the long time strong disturbance of the human population is another important factor that couldn't be ignored.

Photosynthetic characteristics of three tree species seedlings in Changbai Mountain under different CO₂ concentrations

ZHOU Yumei, HAN Shijie, ZHANG Junhui, ZOU Chunjing, WANG Chenrui, CHEN Yongliang

2002, (1):  41-44. 

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The photosynthetic characteristics of three-year-old seedlings of coniferous Pinus koraiensis and Pinus sylvestriformis and broadleaf Fraxinus mandshurica in open-top chambers in Changbai Mountain were studied.Seedlings were planted at four different conditions respectively:elevated CO₂ concentration(700 and 500 μmol·mol^-1)and ambient CO₂ concentration (control chamber and in open field).After treating of two growing seasons in the first two years,seedlings were continuously grown under different CO₂ concentration for another eight weeks.The results indicated that the photosynthetic capacity of three species was enhanced under high CO₂ concentration in the first two growing seasons.The maximum net photosynthetic rates and light response parameters of different tree species were different at the same CO₂ concentration.No photosynthetic acclimation was observed in the third growing season except Pinus sylvestriformis seedlings grown under 500 μmol·mol^-1 CO₂.The increase or decrease of net photosynthetic rates and light response parameters were related to the time of CO₂ treatment.Elevated CO₂ concentration could alter the ability of utilizing strong light and low light of seedlings.

Ecological adaptability of Pennisetum centrasiaticum clones on farmland-sand dune ecotone of Keerqin sandy land

CHEN Shiping, GAO Yubao, REN Anzhi, LIANG Yu, LIU Shuang, LIU Ning

2002, (1):  45-49. 

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The individual growth,morphology and population biomass of Pennisetum centrasiaticum clones at two different habitats of farmland-sand dune ecotone on Keerqin sandy land of Inner Mongolia were compared in this study.P. centrasiaticum clones had significant morphological plasticity and different biomass distribution pattern at different habitats.Compared with P. centrasiaticum clones on semi-fixed sand dunes,those on farmland-sand dune transitive zone had a greater leaf elongation,longer rhizomes and internodes,more adventitious buds,larger amount of biomass,and deeper distribution of underground biomass,which were closely associated with the losse texture of the upper soil and the rather favorable water condition of the lower soil.It is believed that the population can well adapt itself to the farmland-sand dune ecotone habitats,and thus,play an important role in fixing mobile sand in succession of arenaceous vegetation.

Analysis on competition and coexistence patterns of Aneurolepidium chinense and its main companion species

BA Lei, WANG Deli, LIU Ying, WANG Xu, SUN Wei

2002, (1):  50-54. 

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In this study,transects were set in areas where Aneurolepidium chinense and its companion species grew together.Competition and coexistence patterns of these species in the ecotone were analyzed using the following measures:frequency distribution,spatial pattern,and pattern intensity.Patterns of A. chinense and its main companion species were diverse.Aggregation was the tactics for A. chinense to defend the foreign species' invading or disperse itself.There existed competition and coexistence between A. chinense and its main companion species.A. chinense and Phragmite communis competed and coexisted through suppression.A. chinense and Kalimeris interifolia coexisted through competition.Hierochloe glabra and Puccinellia tenuiflora competed with A. chinense through clonal growth.Calamagrostis epigeios was suppressed by A. chinense.

Population physiological indices on density-tolerance of maize in different plant type

XUE Jiquan, LIANG Zongsou, MA Guosheng, LU Haidong, REN Jianhong

2002, (1):  55-59. 

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Taken maize in two plant types of compact-type and flat-type as research object,the relationships between density-tolerance and light distribution in population,indices of productivity(LAI,NAR,and CGR),and population sink-source were studied synthetically by means of crop growth analysis method.The results showed that light distribution in population was the chief index to measure density-tolerance of different maize varieties.The kinetic rules of LAI,NAR,and CGRwere the basic feature reflecting density-tolerance.The correspondent relationship in population sink-source was a comprehensive index to appraise density-tolerance of different maize varieties.

Root growth in rice and its response to soil density

ZHU Defeng, LIN Xianqing, CAO Weixing

2002, (1):  60-62. 

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Studies on root growth and vertical distribution at tillering(TL),panicle initiation(PI),flowering(FL) and mature(MT) stages and effects of soil compaction on root growth were carried out with hybrid rice of Shanyou 63 and 65002 in root box.The results indicated that root weight reached maximum at flowering stage and then decreased.With the advance of growth stage,percentage of deep roots(20～45cm in soil) increased.Root weight increased at highest rate and deep roots formed during the period of TLto PI.With increased soil weight density below 20 cm,root weight and percentage of deep roots markedly decreased.

Effect of fertilization on the qualities of sweet pepper in greenhouse culture

SUI Fanggong, WANG Yunhua, Makoto Nagatomo, Naoya Chishaki, Wunimuren, Shunji Inanagea

2002, (1):  63-66. 

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In order to study the effect of fertilization on the qualities of sweet pepper(Capsicum annul L)cultured in greenhouse,the experiment was carried out by drop irrigation.The results showed that the most sensitive organ of sweet pepper for nitrate was lateral branch,in which the nitrate content was highest.The nitrate content in leaf was lower than that in lateral branch,and in fruit,the nirtate content was the lowest.High fertilization of N,Pand Khad no negative influence on content of nitrate and total soluble sugars in fruit.The content of soluble sugars in fruit were about 50%～55% under all treatment and higher than that in leaf and lateral branch.Decreasing fertilization would cause increasing of the inosital and sucrose contents.Glucose and fructose were the main soluble sugars in fruit.The metabolism of carbohydrates was weakened by high fertilization,and it experessed as restraining the accumulation of starch content in leaf.The content of starch was the highest in fruit.The lipid content were exceed 3～4 times in the leaf than in the lateral branch and fruit,and perhaps,it was due to the hiher content of chlorophyll in the leaf.

Effects of precipitation and soil moisture on N₂O emissions from upland soils in Guizhou

XU Wenbin, LIU Guangshen, LIU Weibing

2002, (1):  67-70. 

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Soils of corn-rape seed rotation,soybean-winter wheat rotation and fallow land in Guizhou were representatively selected to study effects of precipitation and soil moisture on N₂O emissions.Furthermore,DNDC model was used to assess the potential effects of variations in precipitation in future on N₂O emissions from above lands.The results indicated that N₂O emission pulses were obviously driven by rainfall and N₂O fluxes were correlated positively with precipitation and soil moisture.The results from DNDCmodeling showed that N₂O fluxes from soils in summer and autumn would be correlated positively with precipitation,but N₂O fluxes in winter and spring would slightly decrease with great change of precipitation.

Study on the ecological regions of soybean in China Ⅱ Ecological environment and representative varieties

WANG Yusheng, GAI Junyi

2002, (1):  71-75. 

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Based on the climatic and geographical condition,cropping system and season sowing types and maturity group (MG) types of 256 varieties in test from total cultivating regions of soybean in China,six ecological regions of soybean were suggested.Those are:Northern single coropping,spring planting eco-region(Ⅰ),Huanghuaihai double cropping,spring and summer planting eco-region(Ⅱ),Middle and lower Changjiang valley double corpping,spring and summer planting eco-region(Ⅲ),Central south multiple cropping,spring,summer and autumn planting eco-region(Ⅳ),Southwest plateau double cropping,spring and summer planting eco-region(Ⅴ),and South China tropical multiple cropping,all season planting eco-region(Ⅵ).The cultivating environmental condition and representative varieties were shown,and the characteristics of all ecological regions of soybean in China were also discussed in this paper.

Allelopathy of Ageratum conyzoides ⅥEffects of meteorological conditions on allelopathy of Ageratum conyzoides

HU Fei, KONG Chuihua

2002, (1):  76-80. 

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In the field,allelopathic potential of A.conyzoides correlated significantly with sunshine time,temperature and rainfall.Allelopathic potential of A.conyzoides grew in favorable combinate condition of temperature,rainfall and sunshine time,allelopathic potential of A.conyzoides reduced,and vice versa.Allelopathic potential of A.conyzoides decreased because of favorable growing seasons in spring and summer.On the contrary,autumn and winter were unfavorable growing seasons,and the allelopathic potential of A. conyzoides increased.Under laboratory experiments,the volatile oil of A.conyzoides made the tested plants not survive at high concentrations of 300 μg·ml^-1 ,but volatile oil of A.conyzoides inhibited the tested plants slightly at low concentrations of 60 μg·ml^-1.However,under high or low temperatures and shading conditions,inhibitory effects of allelochemicals of A.conyzoides on tested plants intensified significantly at low concentration.It revealed that under unfavorable growing conditions,tested plants resistant ability to the allelochemicals of A.conyzoides decreased.When A.conyzoides and tested plants both grew under unfavorable meteorological conditions,allelopathic potential of A.conyzoides increased,and the tested plants resistant ability to allelochemical decreased.Thus,other plants growing among A.conyzoides in natural community were difficult to grow,and it was relatively improved competitive ability of A.conyzoides in natural communities.Joint effect of allelopathic potential and some meteorological factors such as sunshine time,temperatures,and rainfall was one of the important factors that A.conyzoides was dominated in natural communities.

Landscape pattern analysis based on boundary characteristics

ZENG Hui, KONG Ningning

2002, (1):  81-86. 

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Through boundary number to the length distribution spectrum analysis,the relationships between boundary number-length and fragmentation of landscape and element were discussed.Landscape pattern indices such as diversity,evenness,heterogeneity,and spatial complicity were calculated based on boundary number and cumulative length,and these indices were compared with those based on element area proportion.The results indicated that the fast urbanization process caused complication of boundary element distribution pattern and simplification of layer structure.The distribution function parameter α could reflect landscape fragmentation properly,and the landscape pattern indices based on boundary characteristics was an useful supplement for traditional pattern analysis.

Effects of different mycorrhizal fungi on physiological metabolism of tobacco seedlings

WANG Yuanzhen, KE Yuqin, PAN Tingguo

2002, (1):  87-90. 

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Tobacco seedlings were inoculated with VAmycorrhizal fungi in natural soil.The results showed that compared with the control,the contents of nitrogen,phosphorus,potassium and chlorophyll,nitrate reductase activity,and protein in leaves were higher,malondialdehyde(MDA) and hydrogen peroxide(H₂O₂) decreased,while the activities of superoxide dismutase(SOD),catalase(CAT),and peroxidase(POD) increased.Meanwhile,seedlings were inoculated with two strains of ectomycorrhizal fungi respectively,and the above physiological indices trended the same changes.Moreover,the effect of strain Calvatia lilacina was higher than that of VAmycorrhizal fungi.

CCA of water beetles' distribution and environmental factors in lentic samples of North Changbai Mountain

WE Yulian, JI Lanzhu, WANG Miao, ZHAO Min

2002, (1):  91-94. 

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The relationship between 28 species water beetles in 12 lentic samples and environmental factors of North Changbai Mountain was studied by Cononical Correspondence Analysis (CCA).The results showed that degree of underwater humus and altitude are the major factors correlated with beetles distribution,and the correlation coefficients of envirommental factors and axes of CCAwere 0.8371 and 0.7206 respectively,while water temperature and plant density also had certain effects.Under the influence of environmental factors,the water beetles' populations were different in different habitat.Coelambus impressopunctatus,Colymbetes magnus,Helophorus browni,Haliplus spp.distributed in deep water pool.Water temperature was not important for those beetles.Ilybius sp.and Limnebius glabriventris correlated with altitude and humus.

Main factors influencing the growth of planktonic bacteria in fish pond ecosystem

TAN Hongxin, HU Yuang, MEI Zhiping

2002, (1):  95-100. 

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Focused on the main factors influencing the growth of bacteria in fish pond ecosystem, the variation of abundance in bacterial culture, the effects of substrate on bacterial growth, nutrient uptake and mineralization, the effects of bacterivorous predator and water temperature on bacterial growth were investigated in this paper. The results showed that the growth of bacteria and its uptake of Cand Nwere enhanced by application of inorganic phosphorus into the water, but not by application of organic carbon and nitrogen, and that the Nmineralization was increased by adding organic nitrogen, indicating that the bacterial growth was limited by inorganic Pin the substrate, not by organic Cand N. Among the five test groups,predator bacteria had the slowest growth rate,being lower than the control by 626～154%. The abundance of bacteria,its number increment and growth rate in the fish pond were found to be positively correlated with water temperature in different seasons.In addition,at higher temperature,the positive effects of nutrient application on bacterial growth were enhanced,while the negative effects of predator bacteria on bacterial growth were weakened.

Insecticide resistance of different populations of white-backed planthopper,Sogatella furcifera(Horv醫h)(Homoptera:Delphacidae)

YAO Hongwei, JIANG Caiying, YE Gongyin, CHENG Jiaan

2002, (1):  101-105. 

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Resistance to some insecticides used commonly in different populations of the white-backed planthopper,Sogatella furcifera collected from Zhejiang,Guangxi,Yunnan and Hainan Province in China was measured.The specific activities of some resistance-associated enzymes,i.e.esterase,carboxylesterase,glutathione S-transferase and acetylcholinesterase from these populations were also measured.The resistant levels to malathion,methamidophos,isoprocarb and buprofezin were markedly higher in Yunnan and Hainan populations than in other populations,but considerably more heterogeneity in response to insecticides was found in Zhejiang and Guangxi populations.The specific activities of the enzymes were obviously higher in Zhejiang and Guangxi populations than in Yunnan and Hainan populations,and the distribution range of the enzyme activity was the widest in Zhejiang population,and the narrowest in Guangxi population.Finally,The relationship between the long-distance migration and the territorial difference in insecticide resistant level and activityes of the enzymes in the populations of this planthopper was discussed.

Fluoride accumulation and distribution in mulberry insects near fluoride pollution sources

CHEN Yuyin, LU Shenggao

2002, (1):  106-108. 

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Fluoride accumulation and the relative fluoride loading of different body parts in wild mulberry silkworm (Bombyx mandarina M.), mulberry geometrid (Pathonandria atrineata B.), and mulberry silkworm (Bombyx mori L.) near fluoride pollution sources were studied. Comparison of the fluoride content of insect bodies and mulberry leaves showed that insects collected from polluted sites had increased fluoride accumulation. The digestive tract of the insect had much higher fluoride content than the other parts of the body and was considered to be the important organ of fluoride accumulation. There were also wide differences in fluoride accumulation between different insect species within the same polluted site. The highly significantly correlation between fluoride contents of wild mulberry silkworm, mulberry geometrid, and mulberry silkworm with that of the mulberry leaves on which they were collected was found.

Effects of organic acids on the toxicity of cadmium during ryegrass growth

LIAO Min, HUANG Changyong

2002, (1):  109-112. 

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Effects of low molecular weight organic acids(oxalic acid,citric acid,and acetic acid) and higher molecular weight organic acid(humic acid) on the toxicity of Cd during ryegrass growth were studied.The results showed that Cd toxicity enhanced gradually with increasing the concentration of low molecular weight organic acids,and led to the decreasing of chlorophyll concentration in ryegrass plant and the biomass of ryegrass.The sequence of this influence was:oxalic acid<acetic acid<citric acid.On the contrary,Cd toxicity was reduced as a result of addition of humic acid,and the concentration of chlorophyll in ryegrass shoots and the biomass of ryegrass increased consequently.The concentration of Cd in roots and shoots of the ryegrass increased with increasing the concentration of low molecular weight organic acids,and the sequence of this influence was:citric acid>acetic acid>oxalic acids.The concentration of Cd decreased gradually as a result of increasing the concentration of humic acid,which means humic acid could reduce the toxicity of Cd on ryegrass.Furthermore,the concentration of Cd was higher in roots than in shoots,which indicated that the roots of ryegrass could prevent transport of Cd from roots to shoots and reduce Cd accumulation in the shoots.

Treatment effect of constructed wetlands on organic matter in wastewater from pig farm

LIAO Xindi, LUO Shiming

2002, (1):  113-117. 

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Using plant species Vetiveria zizanioides and Cyperus alternifolius respectively,two constructed wetlands (CWS) with size of 1.0m×0.5m×0.8m were established.The purifying function and its change pattern with season,influent concentration and hydraulic retention time (HRT) of the constructed wetlands on the organic matters in wastewater from a pig farm were studied throughout four seasons in the year.The results showed that the two CWShad very stable effects on the removal of CODand BOD,while the organic matters in wastewater changed.The removal rate of CODand BODwas 70% and 80% respectively by HRT 1～2 d in spring.The removal rate of CODreached 90% with the influent of COD 1000～1400mg·L^-1 in summer.The removal rate of CODand BODwas 50～60% and 50% respectively by HRT 1～2 d in autumn.The removal rate of CODreached 70% with the influent of COD 1003mg·L^-1 in winter.There was no significant difference between two CWSin the removal of COD,BODand SS.The rule of contaminants decreased with the HRTin CWSfollowed exponential function:Y_t=Y₀exp(-kt).The relation between the concentration of contaminants in influent (x) and outflow (y) at the same HRTfollowed linear relation:y=a+bx.

pH of the gill micro-environment of Cyprinus carpio and its effect on the desorption of adsorbed Cu

LONG Aimin, TAO Shu, LIU Changfa

2002, (1):  118-120. 

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pHand CO₂ content differences between fish(Cyprinus carpio) gills micro-environment and the ambient environment were investigated using the technique developed by Playle.The effect of the pHchange on elutriation of copper sorbed on gibbsite was also studied in view of possible desorption of the metal within the gill micro-environment.It was found that there was no pHdifference around pH8.0 and 0.2～0.4 unit difference was observed between the gills' inspired and the expired water when the ambient pHvaried from 8 up to 9.5 or from 8 down to 7.0.Similar trend was detected for CO₂.More Cu adsorbed on the gibbsite can be removed by the acidified expired water from the fish gill micro-environment,comparing to the inspired water.

Classification,application,and creation of landscape indices

CHEN Wenbo, XIAO Duning, LI Xuzhen

2002, (1):  121-125. 

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In landscape ecology,it is very important to understand and grasp the ecological principles of landscape transformation.One of the research methods in common use is to describe landscape pattern and its transformation,and then connect landscape pattern with process by means of landscape indices.Based on the previous studies on landscape indices,some researches on the landscape indices' classification,descriptive ability,relationship among indices and indices' creation were conducted in this paper.Moreover,the general principles of applying landscape indices from two different levels,namely,from single index level and from index system level,were put forward.

Effects of nitrogen and calcium on polyphenol oxidase, peroxidase and leaf spot in carnation

WEI Shenglin, LIU Yehao, QU Haiyong, CAO Jun, YE Hui

2002, (1):  126-127. 

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Carnation inoculated with leaf spot was cultivated under different concentration of nitrogen and calcium in this experiment. The result showed that the nutrition state [NO^-3(0.024%～0.025%),Ca²⁺ (0.022%～0.0342%)] was helpful to keep higher activity of POD and PPOand enhance the carnation's resistance to the germs.