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    15 April 2004, Volume 15 Issue 4
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    Biomass structure and quantitative relationship models of modules in clonal population of Puccinillia chinampoensis in Songnen plain
    LIU Peiyong, ZHANG Qingling, YANG Yunfei
    2004, (4):  543-548. 
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    In this paper,quantitative analysis was conducted at module level on the biomass structure of modules in clonal population of Puccinillia chinampoensis,the relationship between modules' biomass and turf sizes,and the relationship between one module' biomass and another one's.Based on these,the corresponding models of these relationships were established.The results showed that the regularities on the biomass of all functional modules and their ratio were the same at earing stage and at vegetative stage after fruiting.There existed linear correlation between functional modules and turf sizes at earing stage,and exponential correlation at vegetative stage after fruiting.Among all quantitative relationship models,only the one between photosynthesis modules and supporting modules was linear function at earing stage and exponential correlation at vegetative stage after fruiting.The relationship models between any other two functional models were all exponential correlation at two stages.
    Niche characteristics of plants on four environmental gradients in middle reaches of Tarim River
    LIU Jiazhen, CHEN Yaning, ZHANG Yuanming
    2004, (4):  549-555. 
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    Tarim River is the longest continental river in China.Along its either bank,the natural vegetation belts are composed of arbors,shrubs and grasses.In this paper,the niche breadths and overlaps of nineteen species on four environmental gradients in the middle reaches of Tarim River were calculated and analyzed.The results showed that the nineteen species could be divided into three groups,based on their average niche breadths.Group one included Populus euphratica,Tamarix ramosissima,T.hispida,Lycium ruthernicum,Alhagi sparsifolia and Phragmites australis,which were constructive species in Tarim River and their niche breadths were greater.Group two included T.leptostachys,Aeluropus pungens,Poacynum hendersonii,Cynanchum sibiricum,Karelinia caspica,Inula salsoloides,Taraxacum sp.,and Hexinia polydichotoma,and their niche breadths were smaller than that of group one.Group three included Halimodendron halodendron,Glycyrrhiza inflata,Calamagrostis pseudophragmites,Salsola sp.,and Sophora alapecuroides.Based on the niche overlaps matrix,the niche overlaps of the plant species pairs were generally smaller on all the four environmental gradients,because of their probable niche shift or the demand for different environmental resources.Soil moisture and soil salinity were the important environmental factors limiting the plant distribution in the middle reaches of Tarim River.
    Relationship between ephemeral plants distribution and soil moisture on longitudinal dune surface in Gurbantonggut desert
    WANG Xueqin, JIANG Jin, LEI Jiaqiang, ZHAO Congju
    2004, (4):  556-560. 
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    Ephemeral plant is a particular group of desert flora only distributed in northern Xinjiang,China.In this study,field surveys of vegetation and soil moisture were conducted in the southern area of the Gurbantonggut desert from March to August 2002. The species number,coverage and growth of ephemerals and soil moisture were measured in 7 quadrats at different geomorphic positions on the longitudinal dune surface.The results showed that soil moisture in a depth of 0～30 cm affected ephemeral plants distribution significantly.In early spring,the soil moisture was 4.62% on the intredune,3.98% on the plinth,and 2.01% on the crest.Consequently,the average coverage of ephemeral plants reached 51.8%,38.2% and 4.4%,respectively.The existence of ephemeral plants distribution influenced soil moisture as well.In later May,there was an increase of surface soil moisture from the interdune to the crest.The soil moisture was 1.00% on the intredune,1.90% on the plinth,and 2.45% on the crest.
    Analysis on age structure and dynamics of Kindonia uniflora populations
    ZHANG Wenhui, LI Jingxia, LI Hong, LIU Xiangjun
    2004, (4):  561-565. 
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    Kindonia uniflora is a perennial clone herbaceous plant,and also,a native endangered plant in China.This paper studied its age structure,life table and survivorship curve in different habitats in Taibai mountain area.The results indicated that the age structure and dynamics of K.uniflora populations in the Betula utilis forest at altitude 2500～2700m,in the Abies fargesii forest at altitude 2700～2900m,and in the Larix chinensis forest at altitude 2900～3100m had the similar pattern and developing tendency.The number of younger ramets at 1～2 years old or older than 5 years was less,and the number of ramets at 3～5 years old was the highest in the age structures.The negative values of dx (dead number),qx (mortality rate) and Kx (Killing rate) in the life table showed the increasing rate of the population sizes during the age stage.The survivorship curve of K.uniflora populations in different habitats belonged to Deevey C after 3～5 years old.The mortality rate of populations during 5～10 years stage was higher,and was stable after 10 years old.As for the characters of asexual propagation and clone growth,the rhizeomes of the populations were in humus of soil,and developed and expanded as guerilla line style.During growth season,only one leaf grew above ground at every inter-node,and the population growth and development were rarely influenced by external factors.The forest communities,such as Betula utilis,Abies fargesii and Larix chinensis forest,in which K.uniflora populations lived,were at middle or higher mountain,where there were rarely disturbance from human being.Therefore,the habitats for K.uniflora populations to live were relatively stable.As the altitude increased,the disturbances from human being became less,the density of K.uniflora populations increased,the life cycle expanded,the peak of population death delayed,and the population living strategy changed to adapt to the habitats.K.uniflora populations preferred to live in cool climate,thick humus of soil and under shaded forest,therefore,the habitat of communities of Abies fargesii,Larix chinensis forest at altitude 2700～3100m were better than that in Betula utilis forest.The growth and development of K.uniflora populations depended on the habitats;therefore,the communities in which K.uniflora population lived should be conserved firstly.The in-situ conservation of the populations should be encouraged.
    Molecular identification of Araceae-infecting viruses and their ecology
    LIU Wenhong, CHEN Jishuang, LI Yongwei
    2004, (4):  566-570. 
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    A filamentous virus and a spherical virus were detected from partial purification with natural-infected Araceae plants.The filamentous virus was confirmed as dasheen mosaic virus (DsMV) by RNA spot hybridization (RSH) and sequence determination,while the spherical virus was identified as a new strain of cucumber mosaic virus (CMV) by enzyme-linked immunosorbent assay and sequence determination of the 3' end genes of RNA3.CMV was firstly confirmed as one of the principal viruses infecting the Araceae plants under natural condition.According to the sequence similarity of coat protein,Araceae-infecting CMV was then decided belonging to CMV sub-group I,but independent from other isolates in this subgroup.By dot-RNA hybridization to DsMV and CMV probes with total RNA extracted from leaf tissue,field samples collected from some parts of southern China were detected for their natural infection.The infection ratio of field samples infected by DsMV and CMV were 73.3% and 46.7% for samples collected from Hainan Province,100% and 38.5% for those from Hunan Province,93.0% and 38.5% for that from Zhejiang Province,and 100% and no infection for samples from Shanghai,respectively.The infection of viruses on Araceae plants was obviously affected by such ecological factors as geological distribution,climate and host species.The occurrence of CMV was greatly influenced by the above factors,but DsMV always existed as the most commonly distributed virus.
    Diversity of butterflies in Lianhua Mountain Nature Reserve of Dongguan City,Guangdong Province
    LIU Guilin, PANG Hong, ZHOU Changqing, WEN Ruizhen, CHEN Haidong, JIA Fenglong, MO Zhenqiu
    2004, (4):  571-574. 
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    This paper dealt with the diversity of butterflies collected from Lianhua Mountain Nature Reserve of Dongguan in April,June,September and December 2001.In this area,there were 50 species butterflies belonging to 9 families,36 genera.Data analysis showed that the species richness and the highest diversity index were the highest in June,followed by in September,April and December,and the evenness index was the highest in April,then in September,June and December.The dominance index was the highest in December,then in September,June and April.At the level of families,Nymphalidae was the highest in richness,diversity [H'(GS)、H'(G)] and evenness,the second was Papilionidae,and then was Hesperiidae.As for individual quantity,Danaidae was the most abundant,and the following were Pieridae and Papilionidea.For diversity index[H'G(S)],Papiliondae was the highest,and the next was Nymphalidae.
    Pollen combination and paleo-environment of Momoge Lake since 1500 years before
    JIE Dongmei, WANG Shengzhong, GUO Jixun, LÜ Jinfu, LI Jin
    2004, (4):  575-578. 
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    Based on the pollen combination, 14C dating,and depositional facies analysis of Momoge profile in Zhenlai County,Jilin Province,three pollen belts were divided.The results showed that Momoge Lake was formed by blocked paleo-river course depression 1500 years ago,which included three development stages,i.e.,the period when river converted into lake,the early period of lake development,and the steady period.Its corresponding plant types were Artemisia-Chenopodium grassland,Artemisia-Chenopodium grassland accompanied by Betula,and meadow grassland,and its paleo-climate was dry-cold,warm-dry,and then cool-wet,and there was a warm-dry tendency in recent fifty years.
    Ecological management model of agriculture-pasture ecotone based on the theory of energy and material flow—a case study in Houshan dryland area of Inner Mongolia
    FAN Jinlong, PAN Zhihua, ZHAO Ju, ZHENG Dawei, TUO Debao, ZHAO Peiyi
    2004, (4):  579-583. 
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    The degradation of ecological environment in the agriculture-pasture ecotone in northern China has been paid more attentions.Based on our many years' research and under the guide of energy and material flow theory,this paper put forward an ecological management model,with a hill as the basic cell and according to the natural,social and economic characters of Houshan dryland farming area inside the north agriculture-pasture ecotone.The input and output of three models,i.e.,the traditional along-slope-tillage model,the artificial grassland model and the ecological management model,were observed and recorded in detail in 1999.Energy and material flow analysis based on field test showed that compared with traditional model,ecological management model could increase solar use efficiency by 8.3%,energy output by 8.7%,energy conversion efficiency by 19.4%,N output by 26.5%,N conversion efficiency by 57.1%,P output by 12.1%,P conversion efficiency by 45.0%,and water use efficiency by 17.7%.Among the models,artificial grassland model had the lowest solar use efficiency,energy output and energy conversion efficiency;while the ecological management model had the most outputs and benefits,was the best model with high economic effect,and increased economic benefits by 16.1%,compared with the traditional model.
    Evaluation of agricultural net primary productivity in Yijinhuoluo County,Inner Mongolia
    JIA Bingrui, ZHOU Guangsheng
    2004, (4):  584-588. 
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    An agricultural net primary productivity model considering both climatic and fertilizer factors was presented,with referencing over 40 years (1959～1998) climatic and agricultural data from Yijinhuoluo County.Based on the scenarios of climate,population and human activities (mainly fertilization) in the next 30 years as well as the demand of local people for food,the changes of the crop area were evaluated.As a result,622～5948 hm2 could be converted into grassland and forest land from now to the year of 2010,amounting to 3%～31% of the average area between 1990 and 1998; from 2010 to 2020,the converted area should be 3263～8164 hm2,amounting to 17%～42%.In the next 10 years,the area of cropland would rise slightly because of the limitation of increasing yield and population.
    Effect of land-use change on soil habitat in north Hebei plateau during last 50 years
    SHENG Xuebin, LIU Yunxia, SUN Jianzhong
    2004, (4):  589-592. 
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    The change of soil habitat in an area depends on the land-use and cover change in the area to a great extent.Analysis of soil data in north Hebei plateau during last 50 years confirmed that the land-use change,i.e.,the disorder reclamation of a large stretch of natural grassland into cultivated land and the extensive farming,had a series of negative effects on the soil habitat,and made the soil nutrients decreased.During last 50 years,the total and available amount of soil organic matter,N,P,and K decreased by 36.90%,67.77%,44.44%,34.15%,32.22%,58.90% and 35.29%,respectively,and the granulometric contents of sand,silt and clay also varied by 18.24%,19.55%,and 12.29%,respectively,which revealed that in order to ensure the land quality in the regionally important but vulnerable habitat area against the effect of land-use change and its possible degradation with time and to be in sustained dynamic equilibrium,it is necessary to take reasonable fertilization and reliable technical measures.
    Impact of land-use change on soil carbon storage
    WU Jianguo, ZHANG Xiaoquan, XU Deying
    2004, (4):  593-599. 
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    Through comparing the concentration and inventory of soil organic carbon (SOC) and its distribution in soil profiles under cropland,rangeland,natural secondary forest (brushwood,natural secondary forest dominated by Querces liaotungensis or Populus davidiana) and larch plantations (13,18 and 25 years old Larix principis-rupprechtil),this paper studied the effect of land use change from natural secondary forest to cropland or rangeland as well as from cropland or rangeland to plantation on SOC storage in the Liupan mountain forest zone.The results showed that the concentration of SOC in 0～110 cm soil layer under cropland and rangeland was 54% and 27% lower than that under natural secondary forest,respectively.The difference of SOC concentration between natural secondary forest and cropland or rangeland was greater in 0～50 cm than in 50～110 cm soil layer,while that between larch plantations and cropland or rangeland was greater in 0～40 cm than in 40～110 cm soil layer.The inventory of SOC in 0～110 cm soil layer under cropland and rangeland was respectively 35% and 14% lower than that under natural secondary forest,while 23% lower under cropland and 4% higher under rangeland than that under larch plantations.The difference of SOC inventory between natural secondary forest and cropland or rangeland was greater in 0～50 cm than in 50～110 cm soil layer,while that between plantations and cropland or rangeland was greater in 0～30 cm than in 30～110 cm soil layer.The decreasing magnitude of SOC storage with soil profile depth under natural secondary forest or larch plantations was greater than that under cropland or rangeland.The above-mentioned facts resulted from the changes of SOC input or output and the distribution of roots in soil.The results indicated that the SOC concentration and inventory would decline (mainly in 0～50 cm soil layer) after converting from natural secondary forest to cropland or rangeland,but increase (mainly in 0～30 cm soil layer) following afforestation on cropland.The SOC concentration would increase but its inventory would not change following afforestation on rangeland,and the distribution of the SOC concentration or inventory in soil profile would change with the change of land use in Liupan mountain forest zone.
    Community structure and seasonal change of soil micro-arthropodes in the Lower Reaches of Liaohe River Plain under different land utilization
    KE Xin, LIANG Wenju, YU Wantai, XIE Rongdong, WENG Chaolian, YANG Yiming, YIN Wenying
    2004, (4):  600-604. 
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    The data on the soil micro-arthropodes under four land utilization types (fallow,forest,upland field and paddy) in the Lower Reaches of Liaohe River Plain were collected in a period from October 2000 to October 2001.Using the community parameters of population density,group richness,diversity index and evenness,the community structure and its seasonal changes were described.There were 12 groups of soil micro-arthropodes in this region,and of the groups,Collembola and Acarina were dominant,and Diptera,Coleoptera and Hymenoptera were often seen in fallow,forest and upland field,while Collembola,Acarina and Diptera were dominant in paddy.Both land utilization and seasonal change influenced the population density,group richness and diversity index of soil micro-arthropodes.The vertical distribution in both density and group number of arthropods in soil was in the order of surface>middle>bottom.
    Effect of herbicide quinclorac on microbic populations in a paddy soil
    LÜ Zhenmei, MIN Hang, YE Yangfang
    2004, (4):  605-609. 
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    The potential effect of herbicide quinclorac on culturable microorganisms was investigated in a flooded paddy soil added with 0.33,0.67,1.00,1.33,and 2.00 μg quinclorac·g-1 dried soil,by a 10-fold serial dilution plate technique for total soil aerobic bacteria,actinomycetes and fungi,by three-tube anaerobic most-probable-number (MPN) method with anaerobic liquid enrichment media for anaerobic fermentative bacteria (AFB),denitrifying bacteria (DNB) and hydrogen-producing acetogenic bacteria (HPAB),and by the rolling tube method in triplicate for methanogenic bacteria (MB) and nitrogen-fixing bacteria (NFB).The results showed that there were some differences in the aerobic heterotrophic bacteria,AFB and DNB between soils supplemented with quinclorac and non-quinclorac at the early stage of incubation,but none of them was persistent.The numbers of fungi and DNB were increased in soil samples treated with lower than 1.33 μg quinclorac·g-1 dried soil,while the CFU of fungi and HPAB were decreased in soil samples treated by higher than 1.33 μg quinclorac·g-1 dried soil.The population of actinomycete declined in negative proportion to the concentrations of quinclorac applied after 4 days,and the application of quinclorac greatly stimulated the growth of AFB and NFB.MB was more sensitive to quinclorac than the others,but its number in the soil samples with lower concentrations of quinclorac was nearly equal to that in the control on the 33 rd d.It could be concluded that quinclorac was safe to the soil microorganisms when applied at normal concentrations (0.67 μg·g-1 dried soil).
    Spatial distribution pattern of Chilo suppressalis analyzed by classical method and geostatistics
    YUAN Zheming, FU Wei, LI Fangyi
    2004, (4):  610-614. 
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    Two original samples of Chilo suppressalis and their grid,random and sequence samples were analyzed by classical method and geostatistics to characterize the spatial distribution pattern of C.suppressalis.The limitations of spatial distribution analysis with classical method,especially influenced by the original position of grid,were summarized rather completely.On the contrary,geostatistics characterized well the spatial distribution pattern,congregation intensity and spatial heterogeneity of C.suppressalis.According to geostatistics,the population was up to Poisson distribution in low density.As for higher density population,its distribution was up to aggregative,and the aggregation intensity and dependence range were 0.1056 and 193 cm,respectively.Spatial heterogeneity was also found in the higher density population.Its spatial correlativity in line direction was more closely than that in row direction,and the dependence ranges in line and row direction were 115 and 264 cm,respectively.
    Time-concentration-mortality modeling for responses of Myzus persicae to low sublethal sprays of imidacloprid
    DUN Yuhui, FENG Mingguang
    2004, (4):  615-618. 
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    The response of the green peach aphid,Myzus persicae,to low sublethal concentrations of imidacloprid (0.01～1.0 μg·ml-1) sprayed by an electronic sprayer was assessed at the regime of 23℃ and 12:12(L:D) during a 7-day period.The resultant data were fitted to time-concentration-mortality model,generating estimates of lethal concentrations (LCs) and lethal times (LTs) that depended on each other at an expected efficacy level.On days 1 and 5 after spray,for instance,the LC50 with 95% confidential limits were estimated as 2.8(1.8～4.6) and 0.5(0.4～0.6)μg·ml-1,LC90 7.1(3.8～13.0) and 1.2(1.0～1.5),and LC99 11.9(6.0～23.9) and 2.0(1.5～2.8),respectively.At the concentrations of 1.0,2.0 and 3.0 μg·ml-1,the LT50 estimates were 2.9,1.4,and 1.0 days,respectively;and LT90 5.8,3.6,and 2.4 days.The results indicate that the fast knockdown concentration of imidacloprid commonly recommended for field spray in aphid control(～33 μg·ml-1) was even higher than the upper limit of its LC99 within 24 h.Based on the above response of M.persicae to the low sublethal concentrations sprayed,the application rate of imidacloprid for an expected efficacy level against aphids could be greatly decreased if a longer period of action time was allowed.A discussion was given on more rational application of imidacloprid in relation to relief of aphid resistance to the chemical insecticide and its potential to stimulate fertility of spider mites.
    Efficacy of emulsifiable formulations of two entomopathogenic fungi against small green leafhoppers on tea plant
    PU Xiaoying, FENG Mingguang
    2004, (4):  619-622. 
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    A field trial was conducted to test the efficacy of emulsifiable formulations of Beauveria bassiana (Bb) and Paecilomyces fumosoroseus (Pf) conidia in controlling small green leafhoppers (Empoasca spp.) on tea plant in a hillside tea garden located in Shuichang,Zhejiang during mid-summer 2002.Both Bb and Pf formulations contained 10 10 conidia穖l-1.Adding 3% of imidacloprid 10% WP to each fungal formulation (W/V) resulted in two other formulations,i.e.,Bb-imidacloprid mixture (BbIM) and Pf-imidacloprid mixture (PfIM).Besides the four formulations,a mineral oil-based liquid used to formulate the fungal conidia and containing 3% of imidacloprid 10% WP (OBLI) was also tested,and water spray was used as control (CK).Each of the treatments included three 60-m2 plots (replicates),which were sprayed twice with a 500-fold aqueous dilution of the corresponding formulation or preparation at a 12-d interval.Based on the leafhopper densities estimated by sampling in all plots at 3- or 4-d intervals after the first spray,the spray of BbIM or PfIM could better control the leafhoppers than the spray of Bb or Pf formulation.The maximal efficacy relative to CK reached 83.4% and 71.3% in the BbIM and PfIM treatments,respectively.Estimates of field efficacy obtained during the 25-d period after the first spray was 66.8% for BbIM,62.1% for PfIM,50.3% for OBLI,49.5% for Bb,and 19.0% for Pf,respectively.A discussion was also given on the effect of local weather pattern and leafhopper population age structure on the results of the field trial,and on the application techniques to enhance the efficacy of mycoinsecticides against Empoasca species on tea plant.
    Attraction effect of main volatile components from tea shoots and flowers on Sphaerophoria menthastri(Diptera:Syrphidae) and Chrysopa septempunctata(Neuroptera:Chrysopidae)
    HAN Baoyu, ZHOU Chengsong
    2004, (4):  623-626. 
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    The Y-olfactometer bioassays showed that the volatiles from tea aphids and tea aphid-damaged tea shoots(PHC) strongly attracted Sphaerophoria menthastri and Chrysopa septempunctata.At the dosage of 10-4g穖l-1,S.menthastri selected geraniol and methyl salicylate from PHC,n-octanol from intact tea shoots(ITS),nerol from tea flowers(P<0.01),and(E)-2-hexen-1-ol,E-2-hexenal,1,3,6-octatriene-3,7-dimethyl and linalool from PHC(P<0.05),while C.septempunctata selected n-octanol and hexanal from ITS(P<0.05).At the dosage of 10-2g穖l-1,S.menthastri selected hexanal,nerol and benzaldehyde from PHC(P<0.05),while C.septempunctata selected hexanal,benzaldehyde,geraniol and(E)-2-hexen-1-ol(P<0.05).The experimental results showed that besides aldehydes and methyl salicylate,geraniol,n-octanol and(E)-2-hexen-1-ol were significantly attractive to the natural enemies.The selective responses of natural enemies were restricted by thresholds.Both dosages of hexanal significantly attracted C.septempunctata.Nerol might be an infochemicals seducing S.menthastri to orient to tea flowers.
    Comparison of habitats and seasonally differentiated distribution patterns of fig wasp populations associated with Ficus racemosa in Xishuangbanna
    ZHANG Guangming, GU Haiyan, SONG Qishi, XU Lei, PENG Yanqiong, YANG Darong
    2004, (4):  627-633. 
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    The population distribution patterns of fig wasps associated with Ficus racemosa in Xishuangbanna were studied by using several indexes.The results indicated that the distribution patterns of 6 fig wasp species were all clump.The aggregative intensity of pollinating wasp (Ceratosolen fusciceps) population at primeval rain forest was nearly equal to that at seriously disturbed site,whereas they were both much higher than that at moderately disturbed site.In the meanwhile,the population aggregative intensity for the same wasp species was higher in rainy season than in dry-hot season,and the lowest was occurred in foggy-cool season.Non-pollinating wasp (Platyneura testacea,Platyneura mayri,Platyneura agraensis,Apocrypta westwoodi,Apocrypta sp.) population and each of their sex group were varied significantly in aggregative intensity,responding to the habitat change and seasonal alteration.The protection of original habitat should be focused on the protection of the mutualism of Ficus racemosa and fig wasps.
    A dynamic knowledge model for designing suitable sowing date of rice
    YAN Dingchun, ZHU Yan, CAO Weixing
    2004, (4):  634-638. 
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    Based on the summarization,induction and extraction of dynamic relationships between growth characteristics,variety type,farming system and ecological conditions via reading literature and consulting experts,a knowledge model for designing the suitable sowing date of rice under varied environments was developed through knowledge engineering and system analysis methods.The model could precisely quantify the suitable sowing date under different environments and production systems.Case studies for the model with the data sets of daily weather conditions,typical varieties,seedling nursery methods and farming systems at 7 different eco-sites indicated a good performance of the model system in decision-making and its wide applicability,and the model could help farmers to use the resources such as sunshine and water effectively.
    Effect of rice-duck mutualism on nutrition ecology of paddy field and rice quality
    WANG Qiangsheng, HUANG Pisheng, ZHEN Ruohong, JING Liuming, TANG Hebao, ZHANG Chunyang
    2004, (4):  639-645. 
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    The production of nuisanceless rice was conducted by the technique of rice-duck mutualism without applying any pesticide and chemical fertilizer.The results showed that compared to the control,the effect of eliminating weeds was over 99.4%,and the cardinal numbers of plant diseases and insect pests reduced obviously.Nutrients and dissolved oxygen in paddy water and rapidly available nutrients in soil increased,but after maturing stage,compared to basal fertility,rapidly available P and K decreased.The N,P,and K absorption amounts of rice plant,rice yield,setting panicles rate,filled grains and ripened rate increased.The milling,appearance,nutritional,cooking and eating quality of rice improved,especially in reducing chalkiness.The comprehensive benefits of paddy field enhanced obviously.
    Effects of nutrient and water regimes on lodging resistance of rice
    YANG Changming, YANG Linzhang, YAN Tingmei, OUYANG Zhu
    2004, (4):  646-650. 
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    A field experiment was conducted to study the effects of nutrient and water regimes on lodging resistance of rice plant by measuring and comparing the morphological and physical traits and the K2O and SiO2 contents of rice basal stems.The results indicated that a combined application of chemical fertilizers and organic materials,especially and rice straw (CS),could markedly increase the diameter,wall thickness and weight of basal stems,but reduce plant height,which resulted in the effective increase of snapping resistance (RS) and marked decrease of lodging index (LI).The effectiveness of the combined application of chemical fertilizers and rice straw (CS) on the increase of lodging resistance of rice plant was greater in alternate wetting and drying (AWD) and controlled irrigation (DRA),compared to continuous waterlogging (CWL).In addition,the combined application of chemical fertilizers and organic sources,especially with rice straw (CS),greatly increased the K2O and SiO2 contents in rice basal stems,especially in alternate wetting and drying (AWD) and controlled irrigation (DRA).Correlation analysis showed that the wall thickness,weight and snapping resistance of basal stems were significantly positively correlated to the K2O and SiO2 contents in rice basal stems (P<0.05 or P<0.01) in alternate wetting and drying (AWD) and controlled irrigation (DRA).
    Effects of lanthanum on root membrane permeability and nutrient contents in root exudate of rice
    GAO Hongjian, CHANG Jiang, ZHANG Zili, JIANG Xin, ZHAO Zhenhua
    2004, (4):  651-654. 
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    This study showed that when lanthanum was in lower concentration (≤50μg·ml-1),the membrane permeability of rice root was stabilized by decreasing the electrolyte exosmosis,and the contents of K+,Ca2+,P and H+ in root exudate were lower than the control;while the concentration of La3+ was in the range of 100～400 μg·ml-1,the electrolyte exosmosis was reduced in the first 6 hours,and then significantly increased.When the concentration of La3+ was over 500 μg·ml-1,the electrolyte exosmosis was continuously enlarged because of the destruction of the membrane. Under this condition,K+,Ca2+,P and H+ in root exudate were higher than the control.It could be concluded that the concentration of 50 μg·ml-1 La3+ was safe to rice growing.
    Effects of nitrogen forms on roots and N fertilizer efficiency of different wheat cultivars with specialized end-uses
    MA Xinming, WANG Zhiqiang, WANG Xiaochun, WANG Shuli
    2004, (4):  655-658. 
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    A pot experiment showed that under NH2-N treatment,strong gluten wheat Yumai 34 had the highest root biomass,root activity,N use efficiency,N harvest index and grain protein content,but all of these were the lowest under NO3--N treatment.For the medium gluten wheat Yumai 49,the items measured were the highest under NH4+-N treatment,but not the same trend under NO3--N and NH2-N treatments.For the weak gluten wheat Yumai 50,NH4+-N treatment was the best for its top quality and specialized end-uses.There was a significant relationship between grain protein content and N harvest index.
    Effect of low temperature stress on chilling tolerance and protective system against active oxygen of grafted watermelon
    LIU Huiying, ZHU Zhujun, LÜ Guohua
    2004, (4):  659-662. 
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    This paper studied the chilling tolerance and the activity of protective system against active oxygen of own-rooted and grafted watermelon seedlings.The results showed that under low temperature stress,the chilling tolerance of the watermelon seedlings grafted on figleaf was higher than that of the seedlings grafted on Chaofeng F1,and that of the own-rooted seedlings was the lowest.The decrease of chlorophyll,ascorbate and GSH contents and superoxide dismutase,ascorbate peroxidase and dehydroascorbate reductase activities as well as the increase of MDA content in the leaves of both own-rooted and grafted watermelon seedlings indicated an injury on the protective system against active oxygen,and induced lipid peroxidation under low temperature stress.However,the activity of protective system against active oxygen was higher in grafted watermelon seedlings than in own-rooted watermelon seedlings.The activity of protective system against active oxygen in figleaf gourd-grafted watermelon seedlings with stronger chilling tolerance was higher than that of Chaofeng F1-grafted watermelon seedlings with weaker chilling tolerance.It could be concluded that the enhancement of chilling tolerance in grafted watermelon seedlings was related to the increase of antioxidants and antioxidative enzyme activities.
    Physiological and ecological effects of potassium on expansion of crocus corm
    LIU Yun, LONG Yun, ZHU Liquan, CAO Guoxing, ZHONG Zhangcheng
    2004, (4):  663-666. 
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    The corm size of Crocus sativus,a well-known medicine,is a key limiting factor for its stigma harvest.A water cultural experiment with four different potassium (K) concentrations showed that the K content,chlorophyll content,relative ATP content and net photosynthetic rate in C.sativus leaves increased with improving K concentration,which enhanced the function of leaves to be metabolic source.On the other hand,the K absorbing ability and the contents of soluble sugars,vitamin C (Vc) and protein in new-born corms were increased with improving K concentration,which also strengthened the function of new-born corms to be metabolic sink.This study also showed that K could promote the new-born corm growth rate of C.sativus through strengthening the function of “source" and “sink".
    Interactive effect of N and Ca on N uptake by tomato
    LOU Chunrong, HAN Xiaori, XIAO Qianming, SUN Wentao, QIU Weiwen, FU Zhongxin
    2004, (4):  667-672. 
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    To study the effect of fertilizer N and Ca on tomato plant,a pot experiment was conducted with meadow soil in Shenyang.The results showed that under the experimental condition,the N contents in stems,leaves and fruits decreased gradually along with the growth stages.For all treatments,the NO33--N content in fruits,which was within the raw eatable standard,had a positive correlation to N fertilization level.Adequate application of Ca was useful to control the NO33--N content.The response of N contents in stems,leaves and fruits to fertilizer N and Ca was in line with the law of diminishing marginal returns.From flowering stage to fruit expanding stage,the response of fertilizer N was most activated.The nitrate reductase activity in leaves might be greatly affected by fertilizer N,while adequate Ca fertilization could decrease it.A combined application of N and Ca could promote the nitrate reductase activity. Both soil NO33--N content and electric conductivity (EC) were increased with the increasing amount of applied fertilizer N.
    Emergy analysis on an added loop in Spartina alterniflora ecological engineering
    LIU Jin'e, QIN Pei, ZHOU Hongxia, XIE Min
    2004, (4):  673-677. 
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    Based on the principle of multi-grade utilization of resources to get ecological,economic and social benefits of ecological engineering,this paper designed an added loop,following the Spartina alterniflora Ecological Engineering (SAEE).All the added loop design included SAEE,and the capsule was named SAEEC.In the added loop design,the Biological Mineral Liquid (BML) was made into antihyperlipidemia capsules,of which,the total flavonoids added up to 9.58mg穏-1.Emergy analysis method was applied to evaluate the SAEEC project.Compared with SAEE,the added loop design increased emergy investment ratio (EIR) by 1.37 folds,net economic benefit of the SAEEC by 2.13 folds,economic yield /input ratio by 1.46 folds,net emergy yield (NEY) by 3.18 folds,and net emergy yield ratio (EYR) by 2.20 folds,showing its more efficiency.
    Effects of different temperatures on the growth and energy budget of Chinese shrimp,Fenneropenaeus chinensis
    TIAN Xiangli, DONG Shuanglin, WANG Fang
    2004, (4):  678-682. 
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    The effect of temperature on the growth and energy budget of Chinese shrimp Fenneropenaeus chinensis was studied at 18,22,25,28,31 and 34 ℃.The results showed that its specific growth rate in terms of body weight and energy accumulation increased with temperature between 18 ℃ and 31 ℃,and then decreased significantly at 34 ℃.The similar trend was observed in food consumption and apparent digestion rate.The food conversion efficiency in weight and energy were 28.99%～53.09% and 15.70%～7.24%,respectively,which decreased with increasing temperature.The optimum temperature for the growth of shrimp was calculated from the relationship of SGR,which was 29.7 ℃ in this study.The energy budget of shrimp showed that the energy assimilated from food decreased with increasing temperature,while that spent in metabolism increased with increasing temperature.The results indicated that the high growth rate of Chinese shrimp at suitable temperature mainly resulted from the significant increase of food consumption and apparent digestion rate at corresponding temperature regimes.
    Spatial heterogeneity of demersal fish in East China Sea
    SU Fenzhen, ZHOU Chenghu, SHI Wenzhong, DU Yunyan
    2004, (4):  683-686. 
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    Quantitative analysis for the spatial distribution of fish is one of the important methods in fishery or fish ecology research.In this paper,the indexes Geary c and Moran I for the density distribution of demersal fish were calculated,and the semivariograms were drawn.The values of Geary c and Moran I were 0.38 and 0.52,respectively,and the C0/C0+C was 59.9%,which meant that the distribution had a medium spatial autocorrelation with anisotropy,and the heterogeneity caused by random was a little higher than that caused by spatial autocorrelative process.The annual fluctuation of density was caused by the spatial autocorrelation and the random,because the density was significantly positively correlated with the values of C,C0 and C+C0,respectively.
    Characters of greening tree species in heavy metal pollution protection in Shanghai
    YANG Xuejun, TANG Dongqin, XU Dongxin, WANG Xinhua, PAN Gaohong
    2004, (4):  687-690. 
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    In this paper,the stream banks nearby Qibao town and the factory area of Shanghai Baoshan Steel Company were selected as the typical areas contaminated by heavy metals.The polluted status was investigated by measuring the heavy metal concentrations of the sampled soils.The results showed that the heavy metal concentrations in the soils of stream banks were a little higher than the control,but obviously higher in the factory area of Shanghai Baoshan Steel Company.The growth status of the greening trees was recorded,and their heavy metal concentrations were measured by ICP.According to the research results and historic data,the excellent greening tree species mainly applied in polluted factory area were Viburnum awabuki,Lagerstroemia indica,Hibiscus mutabilis,Ligustrum lucidum and Sabina chinensis,which could grow well on contaminated soil,and accumulate high concentrations of heavy metal elements.The other tree species such as Distylium racemosum,Nerium indicum,and Photinia serrulata might be also available in greening for heavy metal pollution protection.
    Relationship between urban green-land landscape patterns and air pollution in the central district of Yichang city
    SHAO Tianyi, ZHOU Zhixiang, WANG Pengcheng, TANG Wanpeng, LIU Xuequan, HU Xingyi
    2004, (4):  691-696. 
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    In this paper,four types of landscape structures and their green-land landscape patterns,including the landscapes of dominant green-land patch pattern,even green-land patch pattern,dominant wooded corridor pattern and building or concrete covering pattern (control) in the central district of Yichang city in Hubei Province,were analyzed respectively on the basis of landscape ecological theory.The atmospheric noise and the contents of SO2,NOx and total suspension particle (TSP) of the landscapes were monitored respectively by comparative method.The results showed that the landscape of building or concrete covering pattern (control) was mostly composed of woodless corridors and building or concrete covering patches with the tiptop green-land fragmentation index (18.125 3 ind穐m-2) and only had 1.00% green-land coverage,which had a relatively higher atmospheric noise and the highest TSP content in the landscape.The landscape of dominant green-land patch pattern had the highest green-land coverage (up to 43.59%) dominated by great green-land patches and the least fragmentation index (0.453 9 ind穐m-2),in which,the atmospheric noise weakened by 28.12% and the TSP content reduced significantly by 86.42%,comparing to the control.The landscape of even green-land patch pattern had the relatively lower green-land coverage (11.34%) and fragmentation index (2.751 1 ind穐m-2),which was mainly composed of the middle or small green-land patches and wooded corridors with a regular distribution.In the landscape,the TSP content reduced obviously by 46.62% of the control,while the effect of dust retention was only 53.95% of that in the landscape of dominant green-land patch pattern.In the landscape of dominant wooded corridor pattern,which was a traffic center and turned into a main pollution resource in the city,there were a relatively higher green-land fragmentation index (6.870 0 ind穐m-2) and the highest wooded corridor density (0.844 3 hm穐m-2) with only 6.13% green-land coverage,and the atmospheric noise and the TSP and NOx content increased by 21.47%,5.08% and 9.06%,respectively,comparing to control.It was obvious that the greater the average area of the green-land patch and the lower the fragmentation index of green-land patches,the more effective the green-land on purifying air pollution.
    Effect of the combination of cadmium and UV-B radiation on soybean growth
    QIANG Weiya, YANG Hui, CHEN Tuo, AN Lizhe, WANG Xunling
    2004, (4):  697-700. 
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    This paper studied the characteristics of soybean growth under the stress of Cd,UV-B radiation and their combination.The results showed that UV-B radiation gave a more pronounced inhibition on soybean growth than cadmium.Under UV-B radiation,the internode differentiation and elongation were inhibited,the internode and plant height were reduced,and the activities of SOD and POD had an apparent increase.Cd2+could antagonize the effect of UV-B radiation on POD activity,and inhibit indole-3-acetic acid(IAA)oxidase activity.A significant decrease of POD and IAA oxidase activities in soybean was detected when exposed to combined UV-B and Cd2+,compared with UV-B radiation only.The decrease of POD and IAA oxidase activities was related to the increase of IAA contents and photosynthetic activity,which might account for the increases of biomass and plant height.Moreover,the combined stress enhanced the inhibition of root growth,and significantly decreased root length.The IAA oxidase and POD activities and photosynthesis rate might be the crucial factors determining the pattern of soybean growth under the stress of Cd2+in combination with UV-B radiation.
    Current situation and some intending problems of landscape spatial dynamic model
    LI Shujuan, ZENG Hui, XIA Jie, ZHANG Lei
    2004, (4):  701-706. 
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    Along with the rapid development of remote sensing,geographic information system,computer and other supporting technologies,model approach has become the major method of landscape dynamic study.Based on literature review,this paper analyzed the current situation and some intending problems of the development of landscape spatial dynamic model.Three kinds of models,i.e.,stochastic landscape model,neighborhood rule model and landscape process model (including percolation model,individual-based landscape model and spatial ecosystem model) were mainly introduced,and their development status,existing problems and related improvement work were analyzed.The development of model test technologies,such as verification analysis,validation analysis,and sensitivity analysis,were also analyzed.Finally,this paper summed up six major problems that should be dealt with in the future development of the landscape spatial dynamic models.These problems included model arithmetic optimization,scale conversion,model complication and predigesting,model test and assessment,bringing forward of general model,and integration of the traditional model with social-economic factors.
    Chemical mechanism of exotic weed invasion
    WANG Peng, LIANG Wenju, KONG Chuihua, JIANG Yong, ZHANG Maoxin, ZHANG Chaoxian
    2004, (4):  707-711. 
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    The ecological and economic impacts of exotic invasive weeds have been followed with interest.A successful invasion of exotic weeds depends not only on their bio-ecological traits,but also on some specific mechanisms of invasion.The clarification of the invasive mechanism of exotic weeds will be beneficial to predict and manage on them.In the process of establishment,reproduction and spreading,an exotic species has to become dominant in the interactions with native ones at new habitats,and then invades successfully.Among invasive mechanisms,the chemical interaction between exotic and native weeds should not be neglected.Previous studies showed that allelopathy plays an important role in exotic weed invasion.In fact,plants are able to defend or inhibit animals,plants and microbes from new habitats by using some specific chemicals.The chemical mechanism of exotic weed invasion might involve each aspect of plant chemical ecology.Therefore,chemical ecological characteristics of exotic weeds should be regarded as one of the most significant factors on predicting invasive species.The studies on chemical mechanism of exotic weed invasion will be one of the important aspects in future.
    Research advances in mechanism of high phosphorus use efficiency of plants
    MA Xiangqing, LIANG Xia
    2004, (4):  712-716. 
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    Phosphorus deficiency is one of the main factors influencing agricultural and forestry productions.Fertilization and soil improvement are the major measures to meet the demand of phosphorus for crops in traditional agriculture and forestry management.Recently,the plants with high phosphorus use efficiency have been discovered to replace the traditional measures to improve phosphorus use efficiency of crops.This paper reviewed the research advances in the morphological,physiological and genetics mechanisms of plants with high phosphorus use efficiency.There were three mechanisms for the plants with high phosphorus use efficiency to grow under phosphorus stress:(1)under low phosphorus stress,the root morphology would change(root system grew fast,root axes became small,the number and density of lateral root increased)and more photosynthesis products would transport from the crown to the root,(2)under low phosphorus stress,plant root exudation increased,mycorrhizae invaded into root system,the feature of root absorption kinetics changed,and the internal phosphorus cycling of plant reinforced to tolerate phosphorus deficiency,and (3) under long selection stress of low phosphorus,some plants would form the genetic properties of phosphorus nutrition that could exploit the hardly soluble phosphorus in the soil.
    Concepts and relative analytical techniques of soil organic matter
    WU Tianyun, Jeff J. Schoenau, LI Fenming, QIAN Peiyuan, ZHANG Shuqing, Sukhadev S. Malhi, WANG Fang
    2004, (4):  717-722. 
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    The research of soil organic matter (SOM) has been highlighted in soil science.In the past 50 years,new perspectives in the relationship between SOM and sustainability of atmosphere and biomosphere,and strong motivation to find a vivid index for soil quality variation induced the transformation in concepts and analytical techniques of SOM:the curiousness to humic substances faded off since they were dull to anthropogenic activities,and interests were focused on the light fraction of organic matter (LFOM),organic carbon associated with different mineral particles in size,particulate and intra-particulate organic matter (POM and iPOM),water soluble organic matter (WSOM),and microbial biomass carbon (MB-C).The relative fractionation procedures have been developed,and the main research activities on SOM are transformed from the products of microorganisms (humus) to the organic matter comprised in plant residues at their various decomposition stages and the organic carbon in microorganisms,since they are biologically active and immediately respond to soil cultivation and tillage,crop rotation,and fertilizer application,etc.
    Research advances in ecophysiological effects of starvation on crustacean
    WU Lixin, DONG Shuanglin, JIANG Zhiqiang
    2004, (4):  723-727. 
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    As a major environmental stress,starvation greatly and extensively affects crustacean in ecophysiological aspects.In this paper,the existing information on the ecophysiological responses of crustacean to starvation,including development and survival,metabolism,digestive gland and enzyme,body composition,and recovery growth was summarized,and on the basis of these,the future research directions,i.e.,the compensatory growth and its mechanism,and the relationship between starvation and immunocompetence,were proposed.
    Influence of different NH4+/NO3- ratios on nitrogen metabolism of cotton
    DONG Hairong, LI Jincai, LI Cundong
    2004, (4):  728-730. 
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    The influence of different NH4+/NO3- ratios on nitrogen metabolism of cotton was studied under controlled hydroponics.The results showed that compared with single nitrate nutrition,solutions with 25/75,50/50,75/25 and 100/0 of NH4+/NO3- significantly increased the soluble protein accumulation in leaves and roots of cotton,and the maximum content of soluble protein in leaves and roots appeared respectively in the solution with 50/50 and 75/25 of NH4+/NO3-.The soluble protein content in roots was increased with the increase of NH4+ percentage,but was slightly less in the solution of 100/0 than 75/25,which was probably related to the excess NH4+ limiting boot metabolism.With the increase of NH4+ percentage,the nitrate content in petiole and the nitrate reductase activity in functional blade declined,but ammoniac nitrogen content increased in every organ of cotton.These results showed that foreign nitrogen affected the nitrogen metabolism of cotton in a different way,and the nitrogen absorption by cotton was probably related to different forms of foreign nitrogen.
    Interactive system of Delphastus catalinae and its competitor:interspecies competition
    JING Ying, HUANG Jian, MA Ruiyan, HAN Jucai
    2004, (4):  731-733. 
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    Delphastus catalinae and Serangium japonicum are the important natural enemies of Bemisia tabaci,of which,the former is exotic,and the latter is indigenous.In this paper,the influence of interspecies competition on the population growth of D.catalinae and S.japonicum was studied under conditions of single and mixed rearing,and Lotka-Volterra equation was used to simulate the competition when more and less preys provided for the two ladybirds.The results showed that the population growth of D.catalinae was greater than that of S.japonicum when single rearing,and the population growth of S.japonicum was greater than that of D.catalinae when mixed rearing.In the competition system of the two ladybirds,S.japonicum was dominant,while D.catalinae could exist simultaneously.
    Effect of different ecological factors on ricefield eel (Monopterus albus) hatching rate
    YIN Shaowu, ZHOU Gongjian, LIU Yun
    2004, (4):  734-736. 
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    This paper studied the effects of some ecological factors (temperature,pH,hatching method and ammonia) on the embryonic development of ricefield eel.The results indicated that the optimum hatching temperature of ricefield eel was 25～28 ℃,and no significant difference was found about the effects of pH within the range of pH 5.5～9.5 on the hatching rate of oosperm.Dripping water incubation had a higher hatching rate of oosperm than staticing water incubation,and the hatching rate of oosperm decreased with increasing ammonia content.The present study provided an available suggestion for the all-artificial and half-artificial breeding of ricefield eel.
    Biomass structure and quantitative relationship models of modules in clonal population of Puccinillia chinampoensis in Songnen plain
    LIU Peiyong, ZHANG Qingling, YANG Yunfei
    2004, (4):  543-548. 
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    In this paper,quantitative analysis was conducted at module level on the biomass structure of modules in clonal population of Puccinillia chinampoensis,the relationship between modules' biomass and turf sizes,and the relationship between one module' biomass and another one's.Based on these,the corresponding models of these relationships were established.The results showed that the regularities on the biomass of all functional modules and their ratio were the same at earing stage and at vegetative stage after fruiting.There existed linear correlation between functional modules and turf sizes at earing stage,and exponential correlation at vegetative stage after fruiting.Among all quantitative relationship models,only the one between photosynthesis modules and supporting modules was linear function at earing stage and exponential correlation at vegetative stage after fruiting.The relationship models between any other two functional models were all exponential correlation at two stages.
    Niche characteristics of plants on four environmental gradients in middle reaches of Tarim River
    LIU Jiazhen, CHEN Yaning, ZHANG Yuanming
    2004, (4):  549-555. 
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    Tarim River is the longest continental river in China.Along its either bank,the natural vegetation belts are composed of arbors,shrubs and grasses.In this paper,the niche breadths and overlaps of nineteen species on four environmental gradients in the middle reaches of Tarim River were calculated and analyzed.The results showed that the nineteen species could be divided into three groups,based on their average niche breadths.Group one included Populus euphratica,Tamarix ramosissima,T.hispida,Lycium ruthernicum,Alhagi sparsifolia and Phragmites australis,which were constructive species in Tarim River and their niche breadths were greater.Group two included T.leptostachys,Aeluropus pungens,Poacynum hendersonii,Cynanchum sibiricum,Karelinia caspica,Inula salsoloides,Taraxacum sp.,and Hexinia polydichotoma,and their niche breadths were smaller than that of group one.Group three included Halimodendron halodendron,Glycyrrhiza inflata,Calamagrostis pseudophragmites,Salsola sp.,and Sophora alapecuroides.Based on the niche overlaps matrix,the niche overlaps of the plant species pairs were generally smaller on all the four environmental gradients,because of their probable niche shift or the demand for different environmental resources.Soil moisture and soil salinity were the important environmental factors limiting the plant distribution in the middle reaches of Tarim River.
    Relationship between ephemeral plants distribution and soil moisture on longitudinal dune surface in Gurbantonggut desert
    WANG Xueqin, JIANG Jin, LEI Jiaqiang, ZHAO Congju
    2004, (4):  556-560. 
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    Ephemeral plant is a particular group of desert flora only distributed in northern Xinjiang,China.In this study,field surveys of vegetation and soil moisture were conducted in the southern area of the Gurbantonggut desert from March to August 2002. The species number,coverage and growth of ephemerals and soil moisture were measured in 7 quadrats at different geomorphic positions on the longitudinal dune surface.The results showed that soil moisture in a depth of 0～30 cm affected ephemeral plants distribution significantly.In early spring,the soil moisture was 4.62% on the intredune,3.98% on the plinth,and 2.01% on the crest.Consequently,the average coverage of ephemeral plants reached 51.8%,38.2% and 4.4%,respectively.The existence of ephemeral plants distribution influenced soil moisture as well.In later May,there was an increase of surface soil moisture from the interdune to the crest.The soil moisture was 1.00% on the intredune,1.90% on the plinth,and 2.45% on the crest.
    Analysis on age structure and dynamics of Kindonia uniflora populations
    ZHANG Wenhui, LI Jingxia, LI Hong, LIU Xiangjun
    2004, (4):  561-565. 
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    Kindonia uniflora is a perennial clone herbaceous plant,and also,a native endangered plant in China.This paper studied its age structure,life table and survivorship curve in different habitats in Taibai mountain area.The results indicated that the age structure and dynamics of K.uniflora populations in the Betula utilis forest at altitude 2500～2700m,in the Abies fargesii forest at altitude 2700～2900m,and in the Larix chinensis forest at altitude 2900～3100m had the similar pattern and developing tendency.The number of younger ramets at 1～2 years old or older than 5 years was less,and the number of ramets at 3～5 years old was the highest in the age structures.The negative values of dx (dead number),qx (mortality rate) and Kx (Killing rate) in the life table showed the increasing rate of the population sizes during the age stage.The survivorship curve of K.uniflora populations in different habitats belonged to Deevey C after 3～5 years old.The mortality rate of populations during 5～10 years stage was higher,and was stable after 10 years old.As for the characters of asexual propagation and clone growth,the rhizeomes of the populations were in humus of soil,and developed and expanded as guerilla line style.During growth season,only one leaf grew above ground at every inter-node,and the population growth and development were rarely influenced by external factors.The forest communities,such as Betula utilis,Abies fargesii and Larix chinensis forest,in which K.uniflora populations lived,were at middle or higher mountain,where there were rarely disturbance from human being.Therefore,the habitats for K.uniflora populations to live were relatively stable.As the altitude increased,the disturbances from human being became less,the density of K.uniflora populations increased,the life cycle expanded,the peak of population death delayed,and the population living strategy changed to adapt to the habitats.K.uniflora populations preferred to live in cool climate,thick humus of soil and under shaded forest,therefore,the habitat of communities of Abies fargesii,Larix chinensis forest at altitude 2700～3100m were better than that in Betula utilis forest.The growth and development of K.uniflora populations depended on the habitats;therefore,the communities in which K.uniflora population lived should be conserved firstly.The in-situ conservation of the populations should be encouraged.
    Molecular identification of Araceae-infecting viruses and their ecology
    LIU Wenhong, CHEN Jishuang, LI Yongwei
    2004, (4):  566-570. 
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    A filamentous virus and a spherical virus were detected from partial purification with natural-infected Araceae plants.The filamentous virus was confirmed as dasheen mosaic virus (DsMV) by RNA spot hybridization (RSH) and sequence determination,while the spherical virus was identified as a new strain of cucumber mosaic virus (CMV) by enzyme-linked immunosorbent assay and sequence determination of the 3' end genes of RNA3.CMV was firstly confirmed as one of the principal viruses infecting the Araceae plants under natural condition.According to the sequence similarity of coat protein,Araceae-infecting CMV was then decided belonging to CMV sub-group I,but independent from other isolates in this subgroup.By dot-RNA hybridization to DsMV and CMV probes with total RNA extracted from leaf tissue,field samples collected from some parts of southern China were detected for their natural infection.The infection ratio of field samples infected by DsMV and CMV were 73.3% and 46.7% for samples collected from Hainan Province,100% and 38.5% for those from Hunan Province,93.0% and 38.5% for that from Zhejiang Province,and 100% and no infection for samples from Shanghai,respectively.The infection of viruses on Araceae plants was obviously affected by such ecological factors as geological distribution,climate and host species.The occurrence of CMV was greatly influenced by the above factors,but DsMV always existed as the most commonly distributed virus.
    Diversity of butterflies in Lianhua Mountain Nature Reserve of Dongguan City,Guangdong Province
    LIU Guilin, PANG Hong, ZHOU Changqing, WEN Ruizhen, CHEN Haidong, JIA Fenglong, MO Zhenqiu
    2004, (4):  571-574. 
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    This paper dealt with the diversity of butterflies collected from Lianhua Mountain Nature Reserve of Dongguan in April,June,September and December 2001.In this area,there were 50 species butterflies belonging to 9 families,36 genera.Data analysis showed that the species richness and the highest diversity index were the highest in June,followed by in September,April and December,and the evenness index was the highest in April,then in September,June and December.The dominance index was the highest in December,then in September,June and April.At the level of families,Nymphalidae was the highest in richness,diversity [H'(GS)、H'(G)] and evenness,the second was Papilionidae,and then was Hesperiidae.As for individual quantity,Danaidae was the most abundant,and the following were Pieridae and Papilionidea.For diversity index[H'G(S)],Papiliondae was the highest,and the next was Nymphalidae.
    Pollen combination and paleo-environment of Momoge Lake since 1500 years before
    JIE Dongmei, WANG Shengzhong, GUO Jixun, LÜ Jinfu, LI Jin
    2004, (4):  575-578. 
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    Based on the pollen combination, 14C dating,and depositional facies analysis of Momoge profile in Zhenlai County,Jilin Province,three pollen belts were divided.The results showed that Momoge Lake was formed by blocked paleo-river course depression 1500 years ago,which included three development stages,i.e.,the period when river converted into lake,the early period of lake development,and the steady period.Its corresponding plant types were Artemisia-Chenopodium grassland,Artemisia-Chenopodium grassland accompanied by Betula,and meadow grassland,and its paleo-climate was dry-cold,warm-dry,and then cool-wet,and there was a warm-dry tendency in recent fifty years.
    Ecological management model of agriculture-pasture ecotone based on the theory of energy and material flow—a case study in Houshan dryland area of Inner Mongolia
    FAN Jinlong, PAN Zhihua, ZHAO Ju, ZHENG Dawei, TUO Debao, ZHAO Peiyi
    2004, (4):  579-583. 
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    The degradation of ecological environment in the agriculture-pasture ecotone in northern China has been paid more attentions.Based on our many years' research and under the guide of energy and material flow theory,this paper put forward an ecological management model,with a hill as the basic cell and according to the natural,social and economic characters of Houshan dryland farming area inside the north agriculture-pasture ecotone.The input and output of three models,i.e.,the traditional along-slope-tillage model,the artificial grassland model and the ecological management model,were observed and recorded in detail in 1999.Energy and material flow analysis based on field test showed that compared with traditional model,ecological management model could increase solar use efficiency by 8.3%,energy output by 8.7%,energy conversion efficiency by 19.4%,N output by 26.5%,N conversion efficiency by 57.1%,P output by 12.1%,P conversion efficiency by 45.0%,and water use efficiency by 17.7%.Among the models,artificial grassland model had the lowest solar use efficiency,energy output and energy conversion efficiency;while the ecological management model had the most outputs and benefits,was the best model with high economic effect,and increased economic benefits by 16.1%,compared with the traditional model.
    Evaluation of agricultural net primary productivity in Yijinhuoluo County,Inner Mongolia
    JIA Bingrui, ZHOU Guangsheng
    2004, (4):  584-588. 
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    An agricultural net primary productivity model considering both climatic and fertilizer factors was presented,with referencing over 40 years (1959～1998) climatic and agricultural data from Yijinhuoluo County.Based on the scenarios of climate,population and human activities (mainly fertilization) in the next 30 years as well as the demand of local people for food,the changes of the crop area were evaluated.As a result,622～5948 hm2 could be converted into grassland and forest land from now to the year of 2010,amounting to 3%～31% of the average area between 1990 and 1998; from 2010 to 2020,the converted area should be 3263～8164 hm2,amounting to 17%～42%.In the next 10 years,the area of cropland would rise slightly because of the limitation of increasing yield and population.
    Effect of land-use change on soil habitat in north Hebei plateau during last 50 years
    SHENG Xuebin, LIU Yunxia, SUN Jianzhong
    2004, (4):  589-592. 
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    The change of soil habitat in an area depends on the land-use and cover change in the area to a great extent.Analysis of soil data in north Hebei plateau during last 50 years confirmed that the land-use change,i.e.,the disorder reclamation of a large stretch of natural grassland into cultivated land and the extensive farming,had a series of negative effects on the soil habitat,and made the soil nutrients decreased.During last 50 years,the total and available amount of soil organic matter,N,P,and K decreased by 36.90%,67.77%,44.44%,34.15%,32.22%,58.90% and 35.29%,respectively,and the granulometric contents of sand,silt and clay also varied by 18.24%,19.55%,and 12.29%,respectively,which revealed that in order to ensure the land quality in the regionally important but vulnerable habitat area against the effect of land-use change and its possible degradation with time and to be in sustained dynamic equilibrium,it is necessary to take reasonable fertilization and reliable technical measures.
    Impact of land-use change on soil carbon storage
    WU Jianguo, ZHANG Xiaoquan, XU Deying
    2004, (4):  593-599. 
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    Through comparing the concentration and inventory of soil organic carbon (SOC) and its distribution in soil profiles under cropland,rangeland,natural secondary forest (brushwood,natural secondary forest dominated by Querces liaotungensis or Populus davidiana) and larch plantations (13,18 and 25 years old Larix principis-rupprechtil),this paper studied the effect of land use change from natural secondary forest to cropland or rangeland as well as from cropland or rangeland to plantation on SOC storage in the Liupan mountain forest zone.The results showed that the concentration of SOC in 0～110 cm soil layer under cropland and rangeland was 54% and 27% lower than that under natural secondary forest,respectively.The difference of SOC concentration between natural secondary forest and cropland or rangeland was greater in 0～50 cm than in 50～110 cm soil layer,while that between larch plantations and cropland or rangeland was greater in 0～40 cm than in 40～110 cm soil layer.The inventory of SOC in 0～110 cm soil layer under cropland and rangeland was respectively 35% and 14% lower than that under natural secondary forest,while 23% lower under cropland and 4% higher under rangeland than that under larch plantations.The difference of SOC inventory between natural secondary forest and cropland or rangeland was greater in 0～50 cm than in 50～110 cm soil layer,while that between plantations and cropland or rangeland was greater in 0～30 cm than in 30～110 cm soil layer.The decreasing magnitude of SOC storage with soil profile depth under natural secondary forest or larch plantations was greater than that under cropland or rangeland.The above-mentioned facts resulted from the changes of SOC input or output and the distribution of roots in soil.The results indicated that the SOC concentration and inventory would decline (mainly in 0～50 cm soil layer) after converting from natural secondary forest to cropland or rangeland,but increase (mainly in 0～30 cm soil layer) following afforestation on cropland.The SOC concentration would increase but its inventory would not change following afforestation on rangeland,and the distribution of the SOC concentration or inventory in soil profile would change with the change of land use in Liupan mountain forest zone.
    Community structure and seasonal change of soil micro-arthropodes in the Lower Reaches of Liaohe River Plain under different land utilization
    KE Xin, LIANG Wenju, YU Wantai, XIE Rongdong, WENG Chaolian, YANG Yiming, YIN Wenying
    2004, (4):  600-604. 
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    The data on the soil micro-arthropodes under four land utilization types (fallow,forest,upland field and paddy) in the Lower Reaches of Liaohe River Plain were collected in a period from October 2000 to October 2001.Using the community parameters of population density,group richness,diversity index and evenness,the community structure and its seasonal changes were described.There were 12 groups of soil micro-arthropodes in this region,and of the groups,Collembola and Acarina were dominant,and Diptera,Coleoptera and Hymenoptera were often seen in fallow,forest and upland field,while Collembola,Acarina and Diptera were dominant in paddy.Both land utilization and seasonal change influenced the population density,group richness and diversity index of soil micro-arthropodes.The vertical distribution in both density and group number of arthropods in soil was in the order of surface>middle>bottom.
    Effect of herbicide quinclorac on microbic populations in a paddy soil
    LÜ Zhenmei, MIN Hang, YE Yangfang
    2004, (4):  605-609. 
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    The potential effect of herbicide quinclorac on culturable microorganisms was investigated in a flooded paddy soil added with 0.33,0.67,1.00,1.33,and 2.00 μg quinclorac·g-1 dried soil,by a 10-fold serial dilution plate technique for total soil aerobic bacteria,actinomycetes and fungi,by three-tube anaerobic most-probable-number (MPN) method with anaerobic liquid enrichment media for anaerobic fermentative bacteria (AFB),denitrifying bacteria (DNB) and hydrogen-producing acetogenic bacteria (HPAB),and by the rolling tube method in triplicate for methanogenic bacteria (MB) and nitrogen-fixing bacteria (NFB).The results showed that there were some differences in the aerobic heterotrophic bacteria,AFB and DNB between soils supplemented with quinclorac and non-quinclorac at the early stage of incubation,but none of them was persistent.The numbers of fungi and DNB were increased in soil samples treated with lower than 1.33 μg quinclorac·g-1 dried soil,while the CFU of fungi and HPAB were decreased in soil samples treated by higher than 1.33 μg quinclorac·g-1 dried soil.The population of actinomycete declined in negative proportion to the concentrations of quinclorac applied after 4 days,and the application of quinclorac greatly stimulated the growth of AFB and NFB.MB was more sensitive to quinclorac than the others,but its number in the soil samples with lower concentrations of quinclorac was nearly equal to that in the control on the 33 rd d.It could be concluded that quinclorac was safe to the soil microorganisms when applied at normal concentrations (0.67 μg·g-1 dried soil).
    Spatial distribution pattern of Chilo suppressalis analyzed by classical method and geostatistics
    YUAN Zheming, FU Wei, LI Fangyi
    2004, (4):  610-614. 
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    Two original samples of Chilo suppressalis and their grid,random and sequence samples were analyzed by classical method and geostatistics to characterize the spatial distribution pattern of C.suppressalis.The limitations of spatial distribution analysis with classical method,especially influenced by the original position of grid,were summarized rather completely.On the contrary,geostatistics characterized well the spatial distribution pattern,congregation intensity and spatial heterogeneity of C.suppressalis.According to geostatistics,the population was up to Poisson distribution in low density.As for higher density population,its distribution was up to aggregative,and the aggregation intensity and dependence range were 0.1056 and 193 cm,respectively.Spatial heterogeneity was also found in the higher density population.Its spatial correlativity in line direction was more closely than that in row direction,and the dependence ranges in line and row direction were 115 and 264 cm,respectively.
    Time-concentration-mortality modeling for responses of Myzus persicae to low sublethal sprays of imidacloprid
    DUN Yuhui, FENG Mingguang
    2004, (4):  615-618. 
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    The response of the green peach aphid,Myzus persicae,to low sublethal concentrations of imidacloprid (0.01～1.0 μg·ml-1) sprayed by an electronic sprayer was assessed at the regime of 23℃ and 12:12(L:D) during a 7-day period.The resultant data were fitted to time-concentration-mortality model,generating estimates of lethal concentrations (LCs) and lethal times (LTs) that depended on each other at an expected efficacy level.On days 1 and 5 after spray,for instance,the LC50 with 95% confidential limits were estimated as 2.8(1.8～4.6) and 0.5(0.4～0.6)μg·ml-1,LC90 7.1(3.8～13.0) and 1.2(1.0～1.5),and LC99 11.9(6.0～23.9) and 2.0(1.5～2.8),respectively.At the concentrations of 1.0,2.0 and 3.0 μg·ml-1,the LT50 estimates were 2.9,1.4,and 1.0 days,respectively;and LT90 5.8,3.6,and 2.4 days.The results indicate that the fast knockdown concentration of imidacloprid commonly recommended for field spray in aphid control(～33 μg·ml-1) was even higher than the upper limit of its LC99 within 24 h.Based on the above response of M.persicae to the low sublethal concentrations sprayed,the application rate of imidacloprid for an expected efficacy level against aphids could be greatly decreased if a longer period of action time was allowed.A discussion was given on more rational application of imidacloprid in relation to relief of aphid resistance to the chemical insecticide and its potential to stimulate fertility of spider mites.
    Efficacy of emulsifiable formulations of two entomopathogenic fungi against small green leafhoppers on tea plant
    PU Xiaoying, FENG Mingguang
    2004, (4):  619-622. 
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    A field trial was conducted to test the efficacy of emulsifiable formulations of Beauveria bassiana (Bb) and Paecilomyces fumosoroseus (Pf) conidia in controlling small green leafhoppers (Empoasca spp.) on tea plant in a hillside tea garden located in Shuichang,Zhejiang during mid-summer 2002.Both Bb and Pf formulations contained 10 10 conidia穖l-1.Adding 3% of imidacloprid 10% WP to each fungal formulation (W/V) resulted in two other formulations,i.e.,Bb-imidacloprid mixture (BbIM) and Pf-imidacloprid mixture (PfIM).Besides the four formulations,a mineral oil-based liquid used to formulate the fungal conidia and containing 3% of imidacloprid 10% WP (OBLI) was also tested,and water spray was used as control (CK).Each of the treatments included three 60-m2 plots (replicates),which were sprayed twice with a 500-fold aqueous dilution of the corresponding formulation or preparation at a 12-d interval.Based on the leafhopper densities estimated by sampling in all plots at 3- or 4-d intervals after the first spray,the spray of BbIM or PfIM could better control the leafhoppers than the spray of Bb or Pf formulation.The maximal efficacy relative to CK reached 83.4% and 71.3% in the BbIM and PfIM treatments,respectively.Estimates of field efficacy obtained during the 25-d period after the first spray was 66.8% for BbIM,62.1% for PfIM,50.3% for OBLI,49.5% for Bb,and 19.0% for Pf,respectively.A discussion was also given on the effect of local weather pattern and leafhopper population age structure on the results of the field trial,and on the application techniques to enhance the efficacy of mycoinsecticides against Empoasca species on tea plant.
    Attraction effect of main volatile components from tea shoots and flowers on Sphaerophoria menthastri(Diptera:Syrphidae) and Chrysopa septempunctata(Neuroptera:Chrysopidae)
    HAN Baoyu, ZHOU Chengsong
    2004, (4):  623-626. 
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    The Y-olfactometer bioassays showed that the volatiles from tea aphids and tea aphid-damaged tea shoots(PHC) strongly attracted Sphaerophoria menthastri and Chrysopa septempunctata.At the dosage of 10-4g穖l-1,S.menthastri selected geraniol and methyl salicylate from PHC,n-octanol from intact tea shoots(ITS),nerol from tea flowers(P<0.01),and(E)-2-hexen-1-ol,E-2-hexenal,1,3,6-octatriene-3,7-dimethyl and linalool from PHC(P<0.05),while C.septempunctata selected n-octanol and hexanal from ITS(P<0.05).At the dosage of 10-2g穖l-1,S.menthastri selected hexanal,nerol and benzaldehyde from PHC(P<0.05),while C.septempunctata selected hexanal,benzaldehyde,geraniol and(E)-2-hexen-1-ol(P<0.05).The experimental results showed that besides aldehydes and methyl salicylate,geraniol,n-octanol and(E)-2-hexen-1-ol were significantly attractive to the natural enemies.The selective responses of natural enemies were restricted by thresholds.Both dosages of hexanal significantly attracted C.septempunctata.Nerol might be an infochemicals seducing S.menthastri to orient to tea flowers.
    Comparison of habitats and seasonally differentiated distribution patterns of fig wasp populations associated with Ficus racemosa in Xishuangbanna
    ZHANG Guangming, GU Haiyan, SONG Qishi, XU Lei, PENG Yanqiong, YANG Darong
    2004, (4):  627-633. 
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    The population distribution patterns of fig wasps associated with Ficus racemosa in Xishuangbanna were studied by using several indexes.The results indicated that the distribution patterns of 6 fig wasp species were all clump.The aggregative intensity of pollinating wasp (Ceratosolen fusciceps) population at primeval rain forest was nearly equal to that at seriously disturbed site,whereas they were both much higher than that at moderately disturbed site.In the meanwhile,the population aggregative intensity for the same wasp species was higher in rainy season than in dry-hot season,and the lowest was occurred in foggy-cool season.Non-pollinating wasp (Platyneura testacea,Platyneura mayri,Platyneura agraensis,Apocrypta westwoodi,Apocrypta sp.) population and each of their sex group were varied significantly in aggregative intensity,responding to the habitat change and seasonal alteration.The protection of original habitat should be focused on the protection of the mutualism of Ficus racemosa and fig wasps.
    A dynamic knowledge model for designing suitable sowing date of rice
    YAN Dingchun, ZHU Yan, CAO Weixing
    2004, (4):  634-638. 
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    Based on the summarization,induction and extraction of dynamic relationships between growth characteristics,variety type,farming system and ecological conditions via reading literature and consulting experts,a knowledge model for designing the suitable sowing date of rice under varied environments was developed through knowledge engineering and system analysis methods.The model could precisely quantify the suitable sowing date under different environments and production systems.Case studies for the model with the data sets of daily weather conditions,typical varieties,seedling nursery methods and farming systems at 7 different eco-sites indicated a good performance of the model system in decision-making and its wide applicability,and the model could help farmers to use the resources such as sunshine and water effectively.
    Effect of rice-duck mutualism on nutrition ecology of paddy field and rice quality
    WANG Qiangsheng, HUANG Pisheng, ZHEN Ruohong, JING Liuming, TANG Hebao, ZHANG Chunyang
    2004, (4):  639-645. 
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    The production of nuisanceless rice was conducted by the technique of rice-duck mutualism without applying any pesticide and chemical fertilizer.The results showed that compared to the control,the effect of eliminating weeds was over 99.4%,and the cardinal numbers of plant diseases and insect pests reduced obviously.Nutrients and dissolved oxygen in paddy water and rapidly available nutrients in soil increased,but after maturing stage,compared to basal fertility,rapidly available P and K decreased.The N,P,and K absorption amounts of rice plant,rice yield,setting panicles rate,filled grains and ripened rate increased.The milling,appearance,nutritional,cooking and eating quality of rice improved,especially in reducing chalkiness.The comprehensive benefits of paddy field enhanced obviously.
    Effects of nutrient and water regimes on lodging resistance of rice
    YANG Changming, YANG Linzhang, YAN Tingmei, OUYANG Zhu
    2004, (4):  646-650. 
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    A field experiment was conducted to study the effects of nutrient and water regimes on lodging resistance of rice plant by measuring and comparing the morphological and physical traits and the K2O and SiO2 contents of rice basal stems.The results indicated that a combined application of chemical fertilizers and organic materials,especially and rice straw (CS),could markedly increase the diameter,wall thickness and weight of basal stems,but reduce plant height,which resulted in the effective increase of snapping resistance (RS) and marked decrease of lodging index (LI).The effectiveness of the combined application of chemical fertilizers and rice straw (CS) on the increase of lodging resistance of rice plant was greater in alternate wetting and drying (AWD) and controlled irrigation (DRA),compared to continuous waterlogging (CWL).In addition,the combined application of chemical fertilizers and organic sources,especially with rice straw (CS),greatly increased the K2O and SiO2 contents in rice basal stems,especially in alternate wetting and drying (AWD) and controlled irrigation (DRA).Correlation analysis showed that the wall thickness,weight and snapping resistance of basal stems were significantly positively correlated to the K2O and SiO2 contents in rice basal stems (P<0.05 or P<0.01) in alternate wetting and drying (AWD) and controlled irrigation (DRA).
    Effects of lanthanum on root membrane permeability and nutrient contents in root exudate of rice
    GAO Hongjian, CHANG Jiang, ZHANG Zili, JIANG Xin, ZHAO Zhenhua
    2004, (4):  651-654. 
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    This study showed that when lanthanum was in lower concentration (≤50μg·ml-1),the membrane permeability of rice root was stabilized by decreasing the electrolyte exosmosis,and the contents of K+,Ca2+,P and H+ in root exudate were lower than the control;while the concentration of La3+ was in the range of 100～400 μg·ml-1,the electrolyte exosmosis was reduced in the first 6 hours,and then significantly increased.When the concentration of La3+ was over 500 μg·ml-1,the electrolyte exosmosis was continuously enlarged because of the destruction of the membrane. Under this condition,K+,Ca2+,P and H+ in root exudate were higher than the control.It could be concluded that the concentration of 50 μg·ml-1 La3+ was safe to rice growing.
    Effects of nitrogen forms on roots and N fertilizer efficiency of different wheat cultivars with specialized end-uses
    MA Xinming, WANG Zhiqiang, WANG Xiaochun, WANG Shuli
    2004, (4):  655-658. 
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    A pot experiment showed that under NH2-N treatment,strong gluten wheat Yumai 34 had the highest root biomass,root activity,N use efficiency,N harvest index and grain protein content,but all of these were the lowest under NO3--N treatment.For the medium gluten wheat Yumai 49,the items measured were the highest under NH4+-N treatment,but not the same trend under NO3--N and NH2-N treatments.For the weak gluten wheat Yumai 50,NH4+-N treatment was the best for its top quality and specialized end-uses.There was a significant relationship between grain protein content and N harvest index.
    Effect of low temperature stress on chilling tolerance and protective system against active oxygen of grafted watermelon
    LIU Huiying, ZHU Zhujun, LÜ Guohua
    2004, (4):  659-662. 
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    This paper studied the chilling tolerance and the activity of protective system against active oxygen of own-rooted and grafted watermelon seedlings.The results showed that under low temperature stress,the chilling tolerance of the watermelon seedlings grafted on figleaf was higher than that of the seedlings grafted on Chaofeng F1,and that of the own-rooted seedlings was the lowest.The decrease of chlorophyll,ascorbate and GSH contents and superoxide dismutase,ascorbate peroxidase and dehydroascorbate reductase activities as well as the increase of MDA content in the leaves of both own-rooted and grafted watermelon seedlings indicated an injury on the protective system against active oxygen,and induced lipid peroxidation under low temperature stress.However,the activity of protective system against active oxygen was higher in grafted watermelon seedlings than in own-rooted watermelon seedlings.The activity of protective system against active oxygen in figleaf gourd-grafted watermelon seedlings with stronger chilling tolerance was higher than that of Chaofeng F1-grafted watermelon seedlings with weaker chilling tolerance.It could be concluded that the enhancement of chilling tolerance in grafted watermelon seedlings was related to the increase of antioxidants and antioxidative enzyme activities.
    Physiological and ecological effects of potassium on expansion of crocus corm
    LIU Yun, LONG Yun, ZHU Liquan, CAO Guoxing, ZHONG Zhangcheng
    2004, (4):  663-666. 
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    The corm size of Crocus sativus,a well-known medicine,is a key limiting factor for its stigma harvest.A water cultural experiment with four different potassium (K) concentrations showed that the K content,chlorophyll content,relative ATP content and net photosynthetic rate in C.sativus leaves increased with improving K concentration,which enhanced the function of leaves to be metabolic source.On the other hand,the K absorbing ability and the contents of soluble sugars,vitamin C (Vc) and protein in new-born corms were increased with improving K concentration,which also strengthened the function of new-born corms to be metabolic sink.This study also showed that K could promote the new-born corm growth rate of C.sativus through strengthening the function of “source" and “sink".
    Interactive effect of N and Ca on N uptake by tomato
    LOU Chunrong, HAN Xiaori, XIAO Qianming, SUN Wentao, QIU Weiwen, FU Zhongxin
    2004, (4):  667-672. 
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    To study the effect of fertilizer N and Ca on tomato plant,a pot experiment was conducted with meadow soil in Shenyang.The results showed that under the experimental condition,the N contents in stems,leaves and fruits decreased gradually along with the growth stages.For all treatments,the NO33--N content in fruits,which was within the raw eatable standard,had a positive correlation to N fertilization level.Adequate application of Ca was useful to control the NO33--N content.The response of N contents in stems,leaves and fruits to fertilizer N and Ca was in line with the law of diminishing marginal returns.From flowering stage to fruit expanding stage,the response of fertilizer N was most activated.The nitrate reductase activity in leaves might be greatly affected by fertilizer N,while adequate Ca fertilization could decrease it.A combined application of N and Ca could promote the nitrate reductase activity. Both soil NO33--N content and electric conductivity (EC) were increased with the increasing amount of applied fertilizer N.
    Emergy analysis on an added loop in Spartina alterniflora ecological engineering
    LIU Jin'e, QIN Pei, ZHOU Hongxia, XIE Min
    2004, (4):  673-677. 
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    Based on the principle of multi-grade utilization of resources to get ecological,economic and social benefits of ecological engineering,this paper designed an added loop,following the Spartina alterniflora Ecological Engineering (SAEE).All the added loop design included SAEE,and the capsule was named SAEEC.In the added loop design,the Biological Mineral Liquid (BML) was made into antihyperlipidemia capsules,of which,the total flavonoids added up to 9.58mg穏-1.Emergy analysis method was applied to evaluate the SAEEC project.Compared with SAEE,the added loop design increased emergy investment ratio (EIR) by 1.37 folds,net economic benefit of the SAEEC by 2.13 folds,economic yield /input ratio by 1.46 folds,net emergy yield (NEY) by 3.18 folds,and net emergy yield ratio (EYR) by 2.20 folds,showing its more efficiency.
    Effects of different temperatures on the growth and energy budget of Chinese shrimp,Fenneropenaeus chinensis
    TIAN Xiangli, DONG Shuanglin, WANG Fang
    2004, (4):  678-682. 
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    The effect of temperature on the growth and energy budget of Chinese shrimp Fenneropenaeus chinensis was studied at 18,22,25,28,31 and 34 ℃.The results showed that its specific growth rate in terms of body weight and energy accumulation increased with temperature between 18 ℃ and 31 ℃,and then decreased significantly at 34 ℃.The similar trend was observed in food consumption and apparent digestion rate.The food conversion efficiency in weight and energy were 28.99%～53.09% and 15.70%～7.24%,respectively,which decreased with increasing temperature.The optimum temperature for the growth of shrimp was calculated from the relationship of SGR,which was 29.7 ℃ in this study.The energy budget of shrimp showed that the energy assimilated from food decreased with increasing temperature,while that spent in metabolism increased with increasing temperature.The results indicated that the high growth rate of Chinese shrimp at suitable temperature mainly resulted from the significant increase of food consumption and apparent digestion rate at corresponding temperature regimes.
    Spatial heterogeneity of demersal fish in East China Sea
    SU Fenzhen, ZHOU Chenghu, SHI Wenzhong, DU Yunyan
    2004, (4):  683-686. 
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    Quantitative analysis for the spatial distribution of fish is one of the important methods in fishery or fish ecology research.In this paper,the indexes Geary c and Moran I for the density distribution of demersal fish were calculated,and the semivariograms were drawn.The values of Geary c and Moran I were 0.38 and 0.52,respectively,and the C0/C0+C was 59.9%,which meant that the distribution had a medium spatial autocorrelation with anisotropy,and the heterogeneity caused by random was a little higher than that caused by spatial autocorrelative process.The annual fluctuation of density was caused by the spatial autocorrelation and the random,because the density was significantly positively correlated with the values of C,C0 and C+C0,respectively.
    Characters of greening tree species in heavy metal pollution protection in Shanghai
    YANG Xuejun, TANG Dongqin, XU Dongxin, WANG Xinhua, PAN Gaohong
    2004, (4):  687-690. 
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    In this paper,the stream banks nearby Qibao town and the factory area of Shanghai Baoshan Steel Company were selected as the typical areas contaminated by heavy metals.The polluted status was investigated by measuring the heavy metal concentrations of the sampled soils.The results showed that the heavy metal concentrations in the soils of stream banks were a little higher than the control,but obviously higher in the factory area of Shanghai Baoshan Steel Company.The growth status of the greening trees was recorded,and their heavy metal concentrations were measured by ICP.According to the research results and historic data,the excellent greening tree species mainly applied in polluted factory area were Viburnum awabuki,Lagerstroemia indica,Hibiscus mutabilis,Ligustrum lucidum and Sabina chinensis,which could grow well on contaminated soil,and accumulate high concentrations of heavy metal elements.The other tree species such as Distylium racemosum,Nerium indicum,and Photinia serrulata might be also available in greening for heavy metal pollution protection.
    Relationship between urban green-land landscape patterns and air pollution in the central district of Yichang city
    SHAO Tianyi, ZHOU Zhixiang, WANG Pengcheng, TANG Wanpeng, LIU Xuequan, HU Xingyi
    2004, (4):  691-696. 
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    In this paper,four types of landscape structures and their green-land landscape patterns,including the landscapes of dominant green-land patch pattern,even green-land patch pattern,dominant wooded corridor pattern and building or concrete covering pattern (control) in the central district of Yichang city in Hubei Province,were analyzed respectively on the basis of landscape ecological theory.The atmospheric noise and the contents of SO2,NOx and total suspension particle (TSP) of the landscapes were monitored respectively by comparative method.The results showed that the landscape of building or concrete covering pattern (control) was mostly composed of woodless corridors and building or concrete covering patches with the tiptop green-land fragmentation index (18.125 3 ind穐m-2) and only had 1.00% green-land coverage,which had a relatively higher atmospheric noise and the highest TSP content in the landscape.The landscape of dominant green-land patch pattern had the highest green-land coverage (up to 43.59%) dominated by great green-land patches and the least fragmentation index (0.453 9 ind穐m-2),in which,the atmospheric noise weakened by 28.12% and the TSP content reduced significantly by 86.42%,comparing to the control.The landscape of even green-land patch pattern had the relatively lower green-land coverage (11.34%) and fragmentation index (2.751 1 ind穐m-2),which was mainly composed of the middle or small green-land patches and wooded corridors with a regular distribution.In the landscape,the TSP content reduced obviously by 46.62% of the control,while the effect of dust retention was only 53.95% of that in the landscape of dominant green-land patch pattern.In the landscape of dominant wooded corridor pattern,which was a traffic center and turned into a main pollution resource in the city,there were a relatively higher green-land fragmentation index (6.870 0 ind穐m-2) and the highest wooded corridor density (0.844 3 hm穐m-2) with only 6.13% green-land coverage,and the atmospheric noise and the TSP and NOx content increased by 21.47%,5.08% and 9.06%,respectively,comparing to control.It was obvious that the greater the average area of the green-land patch and the lower the fragmentation index of green-land patches,the more effective the green-land on purifying air pollution.
    Effect of the combination of cadmium and UV-B radiation on soybean growth
    QIANG Weiya, YANG Hui, CHEN Tuo, AN Lizhe, WANG Xunling
    2004, (4):  697-700. 
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    This paper studied the characteristics of soybean growth under the stress of Cd,UV-B radiation and their combination.The results showed that UV-B radiation gave a more pronounced inhibition on soybean growth than cadmium.Under UV-B radiation,the internode differentiation and elongation were inhibited,the internode and plant height were reduced,and the activities of SOD and POD had an apparent increase.Cd2+could antagonize the effect of UV-B radiation on POD activity,and inhibit indole-3-acetic acid(IAA)oxidase activity.A significant decrease of POD and IAA oxidase activities in soybean was detected when exposed to combined UV-B and Cd2+,compared with UV-B radiation only.The decrease of POD and IAA oxidase activities was related to the increase of IAA contents and photosynthetic activity,which might account for the increases of biomass and plant height.Moreover,the combined stress enhanced the inhibition of root growth,and significantly decreased root length.The IAA oxidase and POD activities and photosynthesis rate might be the crucial factors determining the pattern of soybean growth under the stress of Cd2+in combination with UV-B radiation.
    Current situation and some intending problems of landscape spatial dynamic model
    LI Shujuan, ZENG Hui, XIA Jie, ZHANG Lei
    2004, (4):  701-706. 
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    Along with the rapid development of remote sensing,geographic information system,computer and other supporting technologies,model approach has become the major method of landscape dynamic study.Based on literature review,this paper analyzed the current situation and some intending problems of the development of landscape spatial dynamic model.Three kinds of models,i.e.,stochastic landscape model,neighborhood rule model and landscape process model (including percolation model,individual-based landscape model and spatial ecosystem model) were mainly introduced,and their development status,existing problems and related improvement work were analyzed.The development of model test technologies,such as verification analysis,validation analysis,and sensitivity analysis,were also analyzed.Finally,this paper summed up six major problems that should be dealt with in the future development of the landscape spatial dynamic models.These problems included model arithmetic optimization,scale conversion,model complication and predigesting,model test and assessment,bringing forward of general model,and integration of the traditional model with social-economic factors.
    Chemical mechanism of exotic weed invasion
    WANG Peng, LIANG Wenju, KONG Chuihua, JIANG Yong, ZHANG Maoxin, ZHANG Chaoxian
    2004, (4):  707-711. 
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    The ecological and economic impacts of exotic invasive weeds have been followed with interest.A successful invasion of exotic weeds depends not only on their bio-ecological traits,but also on some specific mechanisms of invasion.The clarification of the invasive mechanism of exotic weeds will be beneficial to predict and manage on them.In the process of establishment,reproduction and spreading,an exotic species has to become dominant in the interactions with native ones at new habitats,and then invades successfully.Among invasive mechanisms,the chemical interaction between exotic and native weeds should not be neglected.Previous studies showed that allelopathy plays an important role in exotic weed invasion.In fact,plants are able to defend or inhibit animals,plants and microbes from new habitats by using some specific chemicals.The chemical mechanism of exotic weed invasion might involve each aspect of plant chemical ecology.Therefore,chemical ecological characteristics of exotic weeds should be regarded as one of the most significant factors on predicting invasive species.The studies on chemical mechanism of exotic weed invasion will be one of the important aspects in future.
    Research advances in mechanism of high phosphorus use efficiency of plants
    MA Xiangqing, LIANG Xia
    2004, (4):  712-716. 
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    Phosphorus deficiency is one of the main factors influencing agricultural and forestry productions.Fertilization and soil improvement are the major measures to meet the demand of phosphorus for crops in traditional agriculture and forestry management.Recently,the plants with high phosphorus use efficiency have been discovered to replace the traditional measures to improve phosphorus use efficiency of crops.This paper reviewed the research advances in the morphological,physiological and genetics mechanisms of plants with high phosphorus use efficiency.There were three mechanisms for the plants with high phosphorus use efficiency to grow under phosphorus stress:(1)under low phosphorus stress,the root morphology would change(root system grew fast,root axes became small,the number and density of lateral root increased)and more photosynthesis products would transport from the crown to the root,(2)under low phosphorus stress,plant root exudation increased,mycorrhizae invaded into root system,the feature of root absorption kinetics changed,and the internal phosphorus cycling of plant reinforced to tolerate phosphorus deficiency,and (3) under long selection stress of low phosphorus,some plants would form the genetic properties of phosphorus nutrition that could exploit the hardly soluble phosphorus in the soil.
    Concepts and relative analytical techniques of soil organic matter
    WU Tianyun, Jeff J. Schoenau, LI Fenming, QIAN Peiyuan, ZHANG Shuqing, Sukhadev S. Malhi, WANG Fang
    2004, (4):  717-722. 
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    The research of soil organic matter (SOM) has been highlighted in soil science.In the past 50 years,new perspectives in the relationship between SOM and sustainability of atmosphere and biomosphere,and strong motivation to find a vivid index for soil quality variation induced the transformation in concepts and analytical techniques of SOM:the curiousness to humic substances faded off since they were dull to anthropogenic activities,and interests were focused on the light fraction of organic matter (LFOM),organic carbon associated with different mineral particles in size,particulate and intra-particulate organic matter (POM and iPOM),water soluble organic matter (WSOM),and microbial biomass carbon (MB-C).The relative fractionation procedures have been developed,and the main research activities on SOM are transformed from the products of microorganisms (humus) to the organic matter comprised in plant residues at their various decomposition stages and the organic carbon in microorganisms,since they are biologically active and immediately respond to soil cultivation and tillage,crop rotation,and fertilizer application,etc.
    Research advances in ecophysiological effects of starvation on crustacean
    WU Lixin, DONG Shuanglin, JIANG Zhiqiang
    2004, (4):  723-727. 
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    As a major environmental stress,starvation greatly and extensively affects crustacean in ecophysiological aspects.In this paper,the existing information on the ecophysiological responses of crustacean to starvation,including development and survival,metabolism,digestive gland and enzyme,body composition,and recovery growth was summarized,and on the basis of these,the future research directions,i.e.,the compensatory growth and its mechanism,and the relationship between starvation and immunocompetence,were proposed.
    Influence of different NH4+/NO3- ratios on nitrogen metabolism of cotton
    DONG Hairong, LI Jincai, LI Cundong
    2004, (4):  728-730. 
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    The influence of different NH4+/NO3- ratios on nitrogen metabolism of cotton was studied under controlled hydroponics.The results showed that compared with single nitrate nutrition,solutions with 25/75,50/50,75/25 and 100/0 of NH4+/NO3- significantly increased the soluble protein accumulation in leaves and roots of cotton,and the maximum content of soluble protein in leaves and roots appeared respectively in the solution with 50/50 and 75/25 of NH4+/NO3-.The soluble protein content in roots was increased with the increase of NH4+ percentage,but was slightly less in the solution of 100/0 than 75/25,which was probably related to the excess NH4+ limiting boot metabolism.With the increase of NH4+ percentage,the nitrate content in petiole and the nitrate reductase activity in functional blade declined,but ammoniac nitrogen content increased in every organ of cotton.These results showed that foreign nitrogen affected the nitrogen metabolism of cotton in a different way,and the nitrogen absorption by cotton was probably related to different forms of foreign nitrogen.
    Interactive system of Delphastus catalinae and its competitor:interspecies competition
    JING Ying, HUANG Jian, MA Ruiyan, HAN Jucai
    2004, (4):  731-733. 
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    Delphastus catalinae and Serangium japonicum are the important natural enemies of Bemisia tabaci,of which,the former is exotic,and the latter is indigenous.In this paper,the influence of interspecies competition on the population growth of D.catalinae and S.japonicum was studied under conditions of single and mixed rearing,and Lotka-Volterra equation was used to simulate the competition when more and less preys provided for the two ladybirds.The results showed that the population growth of D.catalinae was greater than that of S.japonicum when single rearing,and the population growth of S.japonicum was greater than that of D.catalinae when mixed rearing.In the competition system of the two ladybirds,S.japonicum was dominant,while D.catalinae could exist simultaneously.
    Effect of different ecological factors on ricefield eel (Monopterus albus) hatching rate
    YIN Shaowu, ZHOU Gongjian, LIU Yun
    2004, (4):  734-736. 
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    This paper studied the effects of some ecological factors (temperature,pH,hatching method and ammonia) on the embryonic development of ricefield eel.The results indicated that the optimum hatching temperature of ricefield eel was 25～28 ℃,and no significant difference was found about the effects of pH within the range of pH 5.5～9.5 on the hatching rate of oosperm.Dripping water incubation had a higher hatching rate of oosperm than staticing water incubation,and the hatching rate of oosperm decreased with increasing ammonia content.The present study provided an available suggestion for the all-artificial and half-artificial breeding of ricefield eel.