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    15 June 2004, Volume 15 Issue 6
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    Niche characteristics of plant populations in Quercus aliena var. acuteserrata stands in Qinling Mountains
    ZHAO Yonghua, LEI Ruide, HE Xingyuan, JIA Xia
    2004, (6):  913-918. 
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    Based on the data collected from31 plots and using Levins,Hurlbert and Pianka formulas,this paper calculated and analyzed the niche breadths and overlaps of 24 tree and 29 shrub populations in Quercus aliena var. acuteserrata stands in Mt.Qinling,Shaanxi.The results showed that the Levins and Hurlbert's niche breadths of Quercus aliena var. acuteserrata,Pinus armandi,Toxicodendron vernicifluum,Populus davidiana and Pinus tabulaeformis in arbor layer were 3.695,1.695,1.325,0.840,0.702 and 0.036,0.299,0.568,1.721,2.701 respectively,and those of Corrylus heterophylla,Lespedeza formosa and Smilax vaginata in shrub layer were 1.833,1.466,0.984 and 0.111,0.300,0.594,respectively.In general,the niche overlaps between the species with bigger niche breadth and other species were higher,and those of the species having similar environmental requirements were also higher.
    Water conservation functions of several artificial forest ecosystems in semiarid region of western Liaoning Province
    LUO Yuechu, HAN Shanheng, WANG Hongchang, LIU Jianmin, WEI Jing, WU Gang
    2004, (6):  919-923. 
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    Five artificial forest ecosystems in semiarid region of western Liaoning Province were selected to test their water conservation capacity.The average interception rate of different artificial forest ecosystems varied from 14.58% to 37.19%,and the order was H.rhamnoides forest ecosystem> P.tabulaeformis-H.rhamnoides mixed forest ecosystem> P.simonii H.rhamnoides mixed forest ecosystem> P.tabulaeformis forest ecosystem> P.simonii forest ecosystem.The thickness of the litter layer in different forest ecosystems varied from 1.6 to 4.1 cm,and the biomass of the litter varied from 1 890.4 to 6 425.2 kg hm-2.The order of the thickness and the biomass of the litter in different forest ecosystems was H.rhamnoides forest ecosystem> P.tabulaeformis H.rhamnoides mixed forest ecosystem> P.simonii H.rhamnoides mixed forest ecosystem> P.tabulaeformis forest ecosystem> P.simonii forest ecosystem.The maximum water holding capacity of the litter in different forest ecosystems varied form 5 957.7 to 1 9332.9 kg·hm-2,and the order was H.rhamnoides forest ecosystem> P.tabulaeformis H.rhamnoides mixed forest ecosystem> P.simonii H.rhamnoides mixed forest ecosystem> P.tabulaeformis forest ecosystem> P.simonii forest ecosystem.The water holding capacity of non capillary porosity of 0～40 cm soil layer in different forest ecosystems varied from23.70 to 37.85 mm,and the order was H.rhamnoides forest ecosystem> P.simonii H.rhamnoides mixed forest ecosystem> P.tabulaeformis H.rhamnoides mixed forest ecosystem> P.simonii forest ecosystem> P.tabulaeformis forest ecosystem.Among the five artificial forest ecosystems, H.rhamnoides forest ecosystem had the best water conservation capacity,and the mixed forest ecosystems had a better water conservation capacity than P.tabulaeformis and P.simonii forest ecosystem.
    Dynamics and species-diversities of artificial Sonneratia apetala,Sonneratia caseolaris and Kandelia candel communities
    CHEN Yujun, LIAO Baowen, ZHENG Songfa, LI Mei, SONG Xiangyu
    2004, (6):  924-928. 
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    Studies on the dynamics and species diversities of artificial Sonneratia apetala,Sonneratia caseolaris and Kandelia candel communities showed that the arbor layer of S.apetala and S.caseolaris communities contained two distinctive sub layers.The upper layer was composed of S.apetala or S.caseolaris,and the medium layer was composed of K.candel and Aegiceras corniculatum.The dominant population S.apetala or S.caseolaris in S.apetala and S.caseolaris communities only had old aged individuals but no regenerations appeared recently,while K.candel and A.corniculatum were actively progressive populations,which would possibly become dominant populations during the course of community development,showing that S.apetala and S.caseolaris were pioneer species for plantation,which could promote natural colonization of regional mangrove species when planted at open mudflat. K.candel was the actively progressive population in K.candel community,its natural regeneration and succession could be successful,while A.corniculatum and B.sexangula were initially progressive populations.The species composition and species diversities of S.apetala and S.caseolaris communities were similar,both contained the main species in K.candel community,namely, K.candel,A.corniculatum and Bruguiera sexangula,showing that S.apetala and S.caseolaris could co exist with these regional species.To introduce and plant them could help to form complicated and diversified mangrove communities.During the early stage of the development,the species diversities of S.apetala and S.caseolaris communities were higher when their planting density was high.The species diversities grew slightly higher when the communities became older.
    Radiation characteristics in a tropical seasonal rain forest canopy gap
    ZHANG Yiping, DOU Junxia, LIU Yuhong, MA Youxin
    2004, (6):  929-934. 
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    Based on the observation on the radiation with different wavelengths in tropical seasonal rain forest canopy gap,interior of forest,and meteorological station in different seasons,the radiation characteristics of canopy gap were discussed.The results showed that the value of different wavelength radiation had the phenomenon of "suddenly emergent" at the center and north edge of canopy gap.Moreover,each radiation value reached the maximum rapidly,and then decreased quickly around the noon.The daily gross radiation of different wavelengths within the canopy gap was bigger than that in the interior of forest,but smaller than that at meteorological station.Compared to the north edge,the daily gross radiation in the center of the gap was bigger in dry hot season,rain season and later rain season,but smaller in fog cool season,which was influenced by dense fog,solar angle and azimuth.The total daily gross solar radiation at the center was the maximum when the solar angle was the biggest in rain season,higher in later rain season and dry hot season,and was the minimum in fog cool season.The ratios of infrared and visible light radiation to total solar radiation varied with the seasons at the center and north edge of the canopy gap,which fully indicated the environmental heterogeneity within the canopy gap.Compared with meteorological station and interior of forest,the ratios of infrared radiation to total solar radiation in the gap were bigger than those of meteorological station,but smaller than those of interior of forest,which were just contrary to the ratios of visible light to total solar radiation.In addition,the seasonal variation of the ratios of visible light to total solar radiation was higher than that of the ratios of infrared radiation to total solar radiation within the gap.Generally,canopy gap could increase infrared radiation and decrease visible light radiation in tropical seasonal rain forest.
    Effect of phosphorus stress on chlorophyll biosynthesis,photosynthesis and biomass partitioning pattern of Fraxinus mandchurica seedlings
    WU Chu, FAN Zhiqiang, WANG Zhengquan
    2004, (6):  935-940. 
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    Phosphorus is essential to forest trees for their growth and development,because of its important role in many metabolic processes of trees.But,most part of phosphorus in soils of Northeastern China is immobile and unavailable,and thus,many forest trees often suffer from phosphorus stress which affects the biomass accumulation of forest trees.The aim of this study is to understand how the chlorophyll biosynthesis,photosynthesis and biomass partitioning of Fraxinus mandchurica seedlings response to phosphorus stress.Sand culture experiment showed that when the seedlings were under phosphorus stress,their 5 aminolevulinic acid (ALA) biosynthesis rate and porphobilinogen (PBG) synthase activity were reduced,but no significant changes in chlorophyll a and b,total chlorophyll and carotenoid contents were found.The nitrogen content in leaves and roots and the phosphorus content in all parts of seedlings were reduced under phosphorus stress,and the reduction of N content in leaves induced the decrease of maximum quantum efficiency of PSⅡ (Fv/Fm)efficiency of PSⅡ photochemistry (ΦPSⅡ),electron transport rate (ETR),and maximum photosynthesis rate(Amax).The effect of phosphorus stress on chlorophyll biosynthesis didn't affect photosynthesis.Under phosphorus stress,the total biomass decreased,but more biomass was partitioned into roots.
    Snow/wind damage in natural secondary forests in Liaodong mountainous regions of Liaoning Province
    LI Xiufen, ZHU Jiaojun, WANG Qingli, LIU Zugen, HOU Chuansheng, YANG Huanjun
    2004, (6):  941-946. 
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    In early spring of 2003,the secondary forests at the Qingyuan Experimental Forests (QEF) of the Institute of Applied Ecology,Chinese Academy of Sciences suffered from the damage caused by snow and wind (snow/wind damage).This damage occurred at 800 m above sea level was the most serious one since 1949 In order to make clear its occurrence and process and to analyze its possible influences on the secondary forest system,comprehensive investigations were conducted soon after the snow/wind damage.The results showed that the occurrence of this damage was due to the special site conditions (higher sea level and steeper slopes) and air temperature,which suited the wet snow formation and the snow accumulation on trees after a large scale of precipitation.The more seriously damaged areas were those with the stands of Acer mono,Juglans mandshurica,Populus spp. and so on.The ratio of damaged trees was negatively correlated with stand density,soil depth and size class of diameter,and positively correlated with tree height.Based on these results,the likely influences of snow/wind damage,i.e.,the happening of diseases and insect pests,the vegetation changing under forests,and the factors of habitat and dominant species in natural secondary forests were also discussed.It is significant that to do observation and basic research on damaged forests will provide reasonable strategies for management of natural secondary forests.
    Spatial pattern of two dominant shrub populations at transitional zone between oasis and desert of Heihe River Basin
    HE Zhibin, ZHAO Wenzhi
    2004, (6):  947-952. 
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    Based on the field investigation in a 500 m×500 m plot and applying geo statistical theory and methods,this paper described the spatial pattern of the coverage,density,height and volume of two shrub populations Nitraria sphaerocarpa and Reaumuria soongorica at the transitional zone between oasis and desert of Heihe River Basin.The average coverage of the two populations was 1.56±2.34% and 0.23±0.22%,and their average density was 1.5±1.8 clump·100 m-2 and 2.3±2.1 individual·100 m-2,respectively.The height of N. sphaerocarpa was 0.18±0.15 m,and its volume 0.10±0.18 m3. N. sphaerocarpa population exhibited strip distribution pattern,while R. soongorica population showed uniform distribution pattern.The nugget (c0) /sill (c0+c) ratio of the semivariogram of the two populations was 0.08～0.12,which indicates that the random variance of spatial heterogeneity occupied 8%～12%.In semivariogram model,the range value (A0) of the coverage and density was 14.7 and 33.9 m for N. sphaerocarpa,and 25.2 m and 24.9 m for R. soongorica,respectively.As a whole,the random spatial heterogeneity existed at the scale of 10m,and autocorrelated spatial heterogeneity existed at the scale of 34 m.The spatial heterogeneity of the coverage and density of the two dominant populations showed both isotropy and anisotropy,and the isotropy scope of R.soongorica population was larger than that of N.sphaerocarpa.The spatial pattern of N. sphaerocarpa population was controlled by two factors.The first was precipitation and surface runoff,and the second was oasisofication and desertification.
    Effect of land use change on spatial distribution pattern of soil total nitrogen in Keerqin sandy land
    CHEN Fusheng, ZENG Dehui, CHEN Guangsheng
    2004, (6):  953-957. 
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    By using statistics and geostatistics,this paper studied the content and spatial pattern of soil total nitrogen (TN) in a glassland and an arable land of southeast Keerqin sandy land.The TN content in 0～10 cm soil layer of the arable land reclaimed from a glassland 8 years ago was not different from that of the virgin grassland,but the TN content in 10～20 cm soil layer was higher than that in the grassland (P <0.05).The soil TN storage in the grassland was 262.36 g·hm-2 higher than that in the arable land,and its spatial pattern was significantly different between arable land and grassland.The heterogeneity and spatial dependence of TN in each soil layer (0～10 cm and 10～20 cm) of the arable land were larger than those of the grassland,and the ranges and fractal dimensions of TN in each soil layer of the arable land were larger than those of the grassland.There existed a clear horizontal spatial structure heterogeneity and spatial distribution pattern in the arable land,while in the grassland,the horizontal spatial structure heterogeneity was very low,and the horizontal spatial distribution pattern was random and uniform.The TN content in the 0～10 cm and 10～20 cm soil layers of the arable land had no difference (P <0.05),its spatial structure characters had some difference (P <0.05),and its spatial distribution pattern was very similar (r=0.683,P <0.05).The TN content and its spatial structure characters between two soil layers of the grassland had remarkable difference (P <0.05),but its spatial distribution pattern in the two layers was relatively similar (r=0.395,P <0.05).In conclusion,agricultural activity could not only influence soil TN content,but also influence its spatial structure characteristics and spatial distribution pattern.Therefore,our study might promote the further study on the effect of land use change on soil nitrogen distribution pattern and its cycling in ecosystems.
    Effect of cone-picking on natural regeneration of Korean pine in Changbai Mountain Nature Reserve
    LIU Zugen, JI Lanzhu, HAO Zhanqing, ZHU Jiaojun, KANG Hongzhang
    2004, (6):  958-962. 
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    The storage and distribution of Korean pine seeds on Korean pine forest floor in Changbai Mountain Nature Reserve were investigated,and the data were compared with those in 1970s when the forest was little disturbed.Based on the dependence of natural regeneration of Korean pine on seed predating animals,the effect of commercial cone picking on natural regeneration of Korean pine was discussed.The results showed that Korean pine seeds were generally berried under litter layer,and most of them were dropped during cone picking.The density of Korean pine seeds was 1 582～2 640·hm-2,accounted for 0.3%～0.5% of that in 1970s.Furthermore,over 67.8% of these seeds were rotten.Unlike the seeds distributed by squirrel,many (46.7%～77.1%) of them distributed singly.Animals that pick seeds from cone and thus are important for natural regeneration of Korean pine have reduced their population or even disappeared in recent years because most Korean pine cone were collected by people.Therefore,cone picking was one of the obstacles for natural regeneration of Korean pine in Changbai Mountain Nature Reserve.
    Community structure organization and its relation with environmental factors of sown grassland in South China
    XIN Xiaoping, Wang Zongli, YANG Guixia, LI Xianglin
    2004, (6):  963-968. 
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    Contribution of environmental factors,spatial factors,biological and random factors to community structure within a man made grassland in southern terra was partitioned using canonical correspondence analysis.Under mowing and grazing,environmental factors explained (27.4% and 25.9%) variation of community structure.Contribution of spatial factors was 32.5%,24.2%,respectively.Contribution of biological and random factors was 48% and 56%,respectively.Gradient in community structure and species abundance is evident along environmental gradient in mowing grassland.The environment community/species relations were more complex in grazed grassland.Patches under different grazing intensity develop toward different directions.
    Amelioration of secondary bare alkali-saline patches in Songnen Plain through inserting cornstalk.
    HE Nianpeng, WU Ling, JIANG Shicheng, ZHOU Daowei
    2004, (6):  969-972. 
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    Based on the field experiment on Songnen grassland,a new method was established to ameliorate the secondary bare alkali saline patches (SAP) through inserting cornstalk.The experiment was rested on the assumption that through inserting cornstalk in the secondary bare alkali saline patches (SAP) to retain seeds moving over its surface,the necessary seed source could be gained; and these seeds should be able to germinate and survive successfully on the cornstalk itself or in its neighborhood,where should be more fit to grow than other sites in SAP,due to the decomposition of cornstalk and its special role,so that,the aim to restore vegetation of SAP could be achieved at a pretty low cost and rapid speed.The results showed that the seed bank in soil was increased significantly,owing to the inserted cornstalk and its operating processes.The seed number in ameliorated soil was 4 020.0 ?1 773.6 seeds穖-2,while that in the secondary bare alkali saline patches (SAP) was only 10.0?31.6 seeds穖-2.Although the soil chemical and physical characters in ameliorated zone were improved to some extent,the overall situation of soil was still bad for plant growth,as the pH,soluble saline ion and organic matter were concerned.Most of Chloris virgata grew around or on the cornstalk,the plants around each cornstalk being 3.9?2.2,and the total being 48.64?38.72 g穖-2.Therefore,this method demanded a few resources,and needed simple technology and low cost,which is potentially deserved to popularize.
    Consistency between neutral landscape models and real landscape
    WANG Xugao, LI Xiuzhen, HE Hongshi, HU Yuanman
    2004, (6):  973-978. 
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    Neutral landscape models (NLM) can provide standards against real landscapes,and are used to describe landscape pattern and process in the past few decades.In this paper,the neutral landscape models RULE and SimMap were tested against a real landscape,and a set of landscape metrics were used to quantify the spatial characteristics of real and simulated patterns.Measurements of some metrics (total number of patches,total perimeter,average patch area,aggregation index,contagion and lacunarity) suggested that definite level of consistency between NLM generated maps and real landscape did exist at landscape or class levels.But,there were also some metrics,such as corrected patch perimeter area ratio,fractal double logged and edge distribution evenness,which didn't show any agreement between the generated maps and real landscape.In all,each NLM had its own strength in representing real landscape,but none of them was perfect.
    Effect of soil preparation and fertilization on foliage and shoot growth of Ginkgo biloba and its medicine content
    HE Binghui, ZHONG Zhangcheng
    2004, (6):  979-982. 
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    The study showed that the efficiency of various treatments in improving the height growth of Ginkgo biloba was organic fertilizer plus intercropping>soil preparation by blasting plus intercropping>organic fertilizer>soil preparation by blasting>intercropping,and the height growth increased by 14.5%,8.6%,5.7%,3.2% and 0,respectively.The efficiency of the treatments in improving new shoot growth was organic fertilizer plus intercropping>soil preparation by blasting plus intercropping>intercropping>organic fertilizer>soil preparation by blasting,and the new shoot growth increased by 58.1%,36.6%,33.1%,30.2% and 14.0%,respectively.Soil preparation,organic fertilization and intercropping had no different effect on the number of long shoots,but their effect on the numbers of short shoots and leaves was significantly different.The most efficient treatment in improving the medicine content was organic fertilization plus intercropping.Compared with control,the content of quercetin and rutin in Ginkgo biloba leaves increased by 420% and 220%,respectively.
    Nitrogen use efficiency and its relationship with nitrogen nutrition characteristics of wheat varieties
    SUN Chuanfan, DAI Tingbo, JING Qi, JIANG Dong, CAO Weixing
    2004, (6):  983-987. 
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    Forty wheat varieties were tested at two sites (Xuzhou and Nanjing) to evaluate genotypic and environmental variation of nitrogen use efficiency (NUE) and its relationship with nitrogen nutrition characteristics.It was shown that genotype had significant effect on NUE,but environment had less effect on NRE and NFE.All of the nitrogen nutrition traits were significantly influenced by the interaction of genotype譭nvironment.NFE,as an integrated index reflecting the differences of grain yield and nitrogen utilization among different wheat varieties,was significantly correlated with NRE,NPP and NPS,which indicated that it should be more useful in evaluating nitrogen use efficiency.NFE could be improved by increasing N assimilation and translocation after anthesis to effectively increase the N utilization of wheat.
    Soil arthropod communities in different successional tropical secondary forests in Xishuangbanna,SW China
    YANG Xiaodong, TANG Jianwei
    2004, (6):  988-994. 
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    Studies on the soil arthropod community structure and its seasonal variation in four types of secondary forest,including Macaranga denticulate forest(Md), Millettia laptobotrya forest(Ml), Musa acuminata forest(Ma)and Dendrocalamus membranaceae forest(Dm)in Xishuangbanna showed that Acari,Hymenoptera(ant)and Collembola were the dominant groups of soil arthropods on all study sites,but their proportions differed in different forests.For the common and rare groups of soil arthropods,there were some differences in four forests.We found fewer taxonomic groups(number of order),individuals and DG diversity index of soil arthropod communities in Dm secondary forest,as compared to another three forest types.There was no significant difference in number of groups and individuals and DG diversity index of soil arthropods among Md,Ml and Ma.The taxonomic diversity and population of soil arthropods were higher in top soil(0～5 cm)than in deeper layers.The research indicated that the dynamics of soil arthropods was correlated with the fluctuation of temperature and rainfall in this area.In general,the groups,populations and DG diversity index of soil arthropod communities were higher in dry season or early rainy season than in middle rainy season.There were some differences in the seasonal variation of soil arthropod communities in different type forests,which was primarily related to precipitation,temperature,litter quantity and quality,and biology of different soil arthropods.Apparently,food,habitation and disturb also have effects on the seasonal variation of soil arthropod communities in different forests.
    Food nourishment utilization efficiency of different month aged sheep
    WANG Qin, REN Jizhou, WANG Xiaolan, XIA Hong, JIN Lingmei
    2004, (6):  995-999. 
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    Studies on the food nourishment utilization efficiency of different month aged sheep showed that under same food nourishment condition,the ingested nourishment,weight increase,and nourishment depletion per unit weight increase of sheep were increased with the ingestion of dry matter,and the protein content of 34 months old sheep was significantly higher than that of 22 months old sheep (P <0.01),and the latter was significantly higher than that of 10 months old sheep (P <0.01).There was a significant difference of utilization efficiency of the ingested nourishment between 34 months old and 22 months old sheep (P <0.05) and between 10 months old and 22 months old sheep (P <0.01).The weight increase was not significantly different (P >0.05) between 34 months old and 22 months old sheep and between 10 months old and 22 months old sheep,but it was significantly different between 34 months old and 10 months old sheep (P <0.05).The feed conversion rate among them was not different.All the results showed that 10～22 months old sheep had high production efficiency,and could produce high quality mutton,and hence,this section of age was the suitable age of sheep to be butchered.
    Effect of fertilization on soil enzymes and microbes in Larix gemlinii plantations
    CHEN Lixin
    2004, (6):  1000-1004. 
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    One year-old second generation stand and 14 year-and 34 year-old first generation stands in larch plantations were studied at the Maoershan Mt. Experimental Forest Farm. The forestland of these three stands was treated with various fertilizations. The results showed that fertilization could promote or restrain soil enzyme activity and microbial amount with different degrees, and its effect on soil physiological activity was more apparent. The effect of the same fertilisation treatmenu on soil enzyme activity and microbial amount was different at different development stages of the stands. For one year-old stand, the best fertilization scheme was treatment 9, its soil enzyme activities (catalase, proteinase, polyphenoloxidase,urease，and saccharase), total microbial amount, and amount of bacteria, actinomyces and fungus being increased by 413.49%,22.10%，20. 56%，220. 00%，49. 46 %，238. 88 %，247. 24 %,106. 70 %，and 366 . 67 %,respectively, as compared with the mntrol. For 34 year-old stand, the best fertilization scheme was treatment 5, its soil enzyme activities(catalase, proteinase,polyphenoloxidase,urease，and saccharase), total microbial amount, and amount of bacteria and fungus was increased by 30. 44 %，16.91%,0.22%,43.06%，124.18 %，119. 92 %, 87 . 66 %, and 17. 57&，respectively in rhizosphere soil, and by 24 . 55 %，77. 0l %，168.62 %，251. 85 %，183. 33 %, 250. 0 %，38 . 24 % and 128 . 57 %，respectively in non-rhizosphere soil. For 14 year-old young stand, it needed a proper amount of nitrogen fertilizer and organic-mineral fertilizers, and the better fertilisation schemes were treatments 2 and 9. The soil enzyme activities (catslose, proteinase, and，urease)in treatment 2 was increased by 44. 39 %, 94 . 83 %，and 4 . 62 %，respectively in rhizcsphere soil, and by 13 . 98 %，10. 70 % and 129 . 76 %，respectively in non-rhizosphere soil. Total soil microbial amount and the amount of bacteria and fungus in treatment 9 was increased by 176. 49 %, 266. 63&, and 198. 04 %, respectively in rhizcsphere Broil, and by 275 . 56 %, 66. 67 % and 143 . 75 %，respectively in non-rhizasphere soil.
    Variation of microflora and enzyme activity in continuous cropping cucumber soil in solar greenhouse
    MA Yunhua, WEI Min, WANG Xiufeng
    2004, (6):  1005-1008. 
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    Variation of microflora and enzyme activity in solar greenhouse soil continuous cropping for 1,3,5,7,9 years was studied,in addition to the relationship between soil properities and microflora and enzyme activity.The results showed that number of bacteria,actinomyce as well as total microflora showed a trend with a saddle-shaped curve,while the number of fungi appeared an liner increase.Continuous cropping soil microflora shifed from bacteria type to fungi type significiently,of which Ammoniation bacterium and Fusarium oxysporum were main physiology groups.Path analysis results showed that microelements(Mn,Cu,Fe),organic matter,available N and bulk density are main restricted factors of soil microflora and enzyme activity in solar greenhouse.
    Effect of sodium phytate on alkaline phosphatase (ALP) activity in intraradical hyphae of AM fungi and development of its extraradical hyphae
    FENG Haiyan, FENG Gu, WANG Jingguo, LI Xiaolin
    2004, (6):  1009-1013. 
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    In this paper,a pot experiment with three compartments was installed to study the effect of Na-phytate on the development and metabolic activity of AM fungi.Maize was selected as host plant and inoculated with arbuscular mycorrhizal fungus (Glomus intraradices),and different amounts of Na-phytate were applied into hyphal compartments.The results showed that the absorbed P in the shoots and roots of maize inoculated with AM fungi was 1～2 times higher than that of non inoculated maize.The ALP activity in intraradical hyphae of AM fungi was significantly decreased,and the total hyphal density of AM fungi increased with applied Na-phytate.Observations suggested that the ALP activity in intraradical hyphae of AM fungi and the development of its extraradical hyphae could be regulated by Na-phytate.Additionally,AM fungi could enhance the plant's P absorption and utilization from native soil P and additive Na-phytate.
    Response of soil hydrolase and oxidoreductase activities to free-air carbon dioxide enrichment(FACE)under rice-wheat rotation
    ZHANG Yulan, ZHANG Lili, CHEN Lijun, WU Zhijie
    2004, (6):  1014-1018. 
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    This paper studied the response of soil urease,phosphatase,arylsulphatase and dehydrogenase to 200 μmol·mol-1 CO2 elevation under rice-wheat rotation.The results showed that under CO2 elevation,the urease activity in 0～10 cm soil layer was decreased at the early growth stages of wheat but increased at its booting stage;the activity increased at the early growth stages of rice but decreased at its ripening stage.Phosphatase activity was increased during the whole growth period of wheat;the activity increased at the tillering stage of rice but decreased at its later growth stages.Arylsulphatase activity was decreased at the over-wintering and booting stages of wheat but increased at its tillering and ripening stages.Dehydrogenase activity was decreased at the early growth stages of wheat and rice,but increased at their late growth stages.
    Response of soil saccharidase activities to free-air carbon dioxide enrichment (FACE) under rice-wheat rotation
    ZHANG Lili, ZHANG Yulan, CHEN Lijun, WU Zhijie
    2004, (6):  1019-1024. 
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    This paper studied the effect of 200 μmol·mol-1 CO2 elevation on soil saccharidase activities and soil nutrient contents under rice wheat rotation.The results showed that under both wheat and rice planting,CO2 elevation increased soil invertase activity.The elevated CO2 significantly increased soil xylanase activity at the jointing,heading and ripening stages of wheat and at the heading and ripening stages of rice,and slightly decreased soil cellulase activity.Correlation analysis showed that there was a significantly linear positive relationship between soil alkali hydrolyzed nitrogen and soil invertase activity.
    Vertical fractionation of dissolved organic matter in soil profile under water-dry cultivation
    ZHAN Xinhua, CUI Chunhong, LU Yanyu, ZHOU Lixiang
    2004, (6):  1025-1029. 
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    Dissolved organic matter (DOM) is the most active component of organic matters,and plays an important role in the translocation and transformation of pollutants and nutrients in terrestrial ecosystem.In this paper,the vertical fractionation of DOM in a yellow brown soil under water-dry cultivation was investigated by field experiment and physico-chemical analyses.The results showed that in treatments CK,chemical fertilizer and sewage sludge,the DOM concentration decreased from 145.8,117.7 and 114.8 mg穔g-1 to 21.57,23.23 and 13.78 mg穔g-1 with soil depth,respectively.In control and fertilizer-treated soils,the hydrophilic fraction of DOM was increased respectively from 19.01% and 18.47% to 34.97% and 44.37% with soil depth,and the biodegradable rate of DOM also increased with soil depth.In sludge-treated soil,a reverse tendency was found for the concentration of hydrophilic DOM and its biodegradable rate.Hydrophilic fraction decreased from 36.96% to 17.07%,the increase of hydrophobic fraction was from 63.04% to 82.93%,and the biodegradable rate decreased from 53.19% to 30.75% with soil depth.The biodegradable rate of DOM was positively correlated to the hydrophilic fraction of DOM,and UV spectra analysis also suggested this.
    Bacteria ecology in planting-culturing system
    HUANG Fenglian, XIA Beicheng, DAI Xin, CHEN Guizhu
    2004, (6):  1030-1034. 
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    ng system in inter tidal zone is a new type eco-culturing model.The survey on bacteria biomass and water quality in the designed planting culturing system in inter-tidal zone showed that the mangrove planted in the system improved water quality and made water quality to Ⅱ～Ⅲ type,better than the Ⅳ and Ⅴ type in the control pond.Designed ponds made heterotrophic bacteria,vibrio,phosphorus bacteria and enzyme-producing bacteria populations 1～2 order lower than the control pond without mongrove planting.Correlation analyses with CORREL software showed that the biomass of these bacteria was positively related with the nitrogen and phosphorus contents in water of the system,and the correlation coefficient for heterogeneous bacteria and vibrio was up to 0.9205.Heterotrophic bacteria and vibrio could be used as the water-quality monitoring organisms.
    Effect of temperature on Macrosiphoniella sanborni development
    DUAN Jinhua, ZHANG Runjie
    2004, (6):  1035-1038. 
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    The development of Macrosiphoniella sanborni was studied at 15～35 ℃ and 80% RH,and the data obtained were used to determine the rate and threshold of its development and the sum of effective temperature.The optimal temperature for M.sanborni development ranged from 22 ℃ to 25 ℃.After fitting the data to Wang Rusong's model,the development rate V(t) increased with rising temperature.The 2nd and 3rd instar nymphs were found more tolerable to extreme temperature and had higher optimal temperature than 1st and 4th instar nymphs.The temperature tolerance value δ was 6.70 for the 2nd and 3rd instars,and 4.70 and 4.50 for the 1st and 4th instars,respectively. The optimal temperature for the 2nd and 3rd instar was 21.76 ℃,and the highest development temperature was 40.97 ℃,while for the 1st and 4th instar,the optimal temperature was 23.76 ℃ and 22.49 ℃,and the highest development temperature was 39.97 ℃ and 40 56 ℃,respectively.Calculations with direct optimum estimation method showed that the threshold of development decreased with the aging of nymphs,while the effective accumulative temperature increased.For the 1st,2nd,3rd and 4th instar,the threshold of development was 6.93,5.02,4.58 and 4.46 ℃,and the effective accumulative temperature was 26.88,33.41,33.63 and 48.49 ℃·d-1,respectively.
    Spatial structure of populations Myzus persicae and its predatory natural enemy Erigonidium graminicola
    WU Houzhang, XU Guangshu, FANG Minghui, CHENG Xianian, ZOU Yunding
    2004, (6):  1039-1042. 
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    In this paper,the spatial construction models of populations M. persicae and its predatory natural enemy E. graminicola during different periods were simulated by geostatistics,and their spatial relationships were analyzed.The spatial structure of M. persicae population was described by spherical model,showing an aggregated spatial arrangement.Its spatial dependence was 2.0252～4.1495 m,heterogeneity degree was 10 281.36～ 300 216.30, and sample variance was 12 176.81～303 433.70.The spatial structure of E. graminicola population was also simulated by spherical model,showing an aggregated spatial arrangement.Its spatial dependence was 3.7328～4.8983 m,heterogeneity degree was 1.4482～4.4134,and sample variance was 1.6941～5.8167.The results and methods could be applied to monitor the temporal and spatial dynamics of target insect pest population in tobacco field,and provide scientific basis for ecological control.
    Geostatistic analysis on spatial patterns of Aphis gossypii and Erigonidium graminicola
    LI Lei, ZOU Yunding, BI Shoudong, GAO Caiqiu, DING Chengcheng, MENG Qinglei, LI Changgen, ZHOU Xiazhi
    2004, (6):  1043-1046. 
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    The spatial structure and spatial correlativity of Aphis gossypii and Erigonidium graminicola populations during different periods were investigated by geostatistic methods.The results showed that the semivariogram of A.gossypii appeared as spherical type,indicating its spatial pattern was an aggregated type with a range of 7.33～12.40 cm,while that of E.graminicola was also fitted into spherical model,indicating an aggregated spatial arrangement with a range of 6.47～20.88 cm.The amount and spatial distribution of E.graminicola were closely related to those of A.gossypii,suggesting that E.graminicola was the dominant natural enemy influencing A.gossypii population.
    Emergy evaluation of power plant eco-industrial park
    WANG Lingmei, ZHANG Jintun
    2004, (6):  1047-1050. 
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    In this paper,new emergy indices for the material circulation utilization and energy cascade utilization were presented to evaluate the emergy of power plant eco industrial park.The common contribution of the members in power plant eco industrial park should be accounted for emergy yield ratio (PEYR) and emergy investment ratio (PEIR),namely, PEYR= (Fi+Ri+Ni)/ Fi and PEIR= Fi/ (Ni+Ri).Saved renewable and nonrenewable resources and purchased resources and decreased environmental load should be accounted for environmental loading ratio (PELR) and index of sustainability (PESI),namely, PELR= Fi/F' and PESI=PEYR/PELR.Case analysis on the Shuozhou power plant eco industrial park showed that new emergy indices were practical in evaluating the power plant eco-industrial park.
    Concept and methodology on up-scaling issue of small watershed prototypes for reconstructing ecological economies in Loess Plateau
    CHENG Xu, LIU Guobin, CHEN Youqi, CHANG Xin
    2004, (6):  1051-1055. 
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    The general ecological situation of Loess Plateau is kept deteriorating,despite great efforts have been made and some achievements were gained after 50 years' endeavor to control soil erosion and renovate ecological landscape.Investigations on the past 20 years results from 11 experimental sites showed that the extension of prototypes and models derived from these sites,which were all based on one scale of small watershed,were unsatisfactory.The possible reasons for such a situation could be attributed to the too coarse scale of map,on which,the regional planning were set up and the locations of these experiment sites were decided,the too fine scale of the small watershed which were usually 3～10 km2 in size,the shortage of studies on various scales particularly on the meso-scale,and the lack of methods of scaling on up-scaling.Based on the analysis of restraints in management of small watershed,the specific concept and relevant proposed methods of resemblance-scaling and multi-scale complementarity were put forward and tested.
    Sensitivity analysis in ecological modeling
    XU Chonggang, HU Yuanman, CHANG Yu, JIANG Yan, LI Xiuzhen, BU Renchang, HE Hongshi
    2004, (6):  1056-1062. 
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    Sensitivity analysis is used to qualitatively or quantitatively apportion the variation of model output to different source of variation.It is a very useful tool in model parameterization and calibration,and has important ecological significance by identifying the governing factors for a certain ecological process simulated.There are two schools of sensitivity analysis, local sensitivity analysis and global sensitivity analysis.The former examines the local response of the output(s) by varying input parameters one at a time,holding other parameters to a central value; and the latter examines the global response (averaged over the variation of all the parameters) of model output(s) by exploring a finite (or even an infinite) region.Since it is very easy to conduct local sensitivity analysis,it is very popular in ecological models.However,local sensitivity analysis is not computationally effective,because it can only get the sensitivity of a single parameter at a time.It can not take into consideration the effect of interaction of different parameters.Additionally,the value of other parameters will affect the sensitivity of the parameter specified.In view of this,global sensitivity analysis is increasingly preferred to local sensitivity in recent years.However,for most of the ecological modeling study published in Chinese,only local sensitivity analysis is conducted.To provide a toolbox of alternative sensitivity analysis algorithms for ecological model development in future study,we reviewed the main methods of both local sensitivity analysis and global sensitivity analysis,including one at a time method,multivariate regression,Morris' method,Sobol's method,Fourier Amplitude Sensitivity Analysis,and Extended Fourier Amplitude Sensitivity Analysis.Based on the state-of-the-art research on sensitivity analysis,the sensitivity of the interaction between two or more than two model parameters,the sensitivity of common model parameters in a set of models,and the sensitivity analysis in spatially explicit landscape model simulation were identified as the key areas and difficulties of future study on sensitivity analysis in ecological modeling.
    Response of fine roots to soil nutrient spatial heterogeneity
    WANG Qingcheng, CHENG Yunhuan
    2004, (6):  1063-1068. 
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    The spatial heterogeneity is the complexity and variation of systems or their attributes,and the heterogeneity of soil nutrients is ubiquitous in all natural ecosystems.The scale of spatial heterogeneity varies considerably among different ecosystems,from tens of centimeters to hundred meters.Some of the scales can be detected by individual plant.Because the growth of individual plants can be strongly influenced by soil heterogeneity,it follows that the inter specific competition should also be affected.During the long process of evolution,plants developed various plastic responses with their root system,including morphological,physiological and mycorrhizal plasticity,to maximize the nutrient acquisition from heterogeneous soil resources.Morphological plasticity,an adjustment in root system spatial allocation and architecture in response to spatial heterogeneous distribution of available soil resources,has been most intensively studied,and root proliferation in nutrient rich patches has been certified for many species.The species that do response may have an increased rate of nutrient uptake,leading to a competitive advantage.Scale and precision are two important features employed in describing the size and foraging behavior of root system.It was hypothesized that scale and precision is negatively related,i.e.,the species with high scale of root system tend to be a less precise forager.The outcomes of different research work have been diverse,far from reaching a consensus.Species with high scale are not necessarily less precise in fine root allocation,and vice versa.The proliferation of fine root in enriched micro-sites is species dependent,and also affected by other factors,such as patch attributes (size and nutrients concentration),nutrients,and overall soil fertility.Beside root proliferation in nutrient enriched patches,plants can also adapt themselves to the heterogeneous soil environment by altering other root characteristics such as fine root diameter,branch angle,length,and spatial architecture of root system.Physiological and mycorrhizal plasticity can add some influence on the morphological plasticity to some extent,but they are less studied.Roots located in different patches can quickly regulate their nutrient uptake kinetics within different nutrient patches,and increase overall nutrient uptake.Physiological response may,to certain extent,reduce morphological response,and is meaningful for plant growth on soils with frequently changing spatial and temporal heterogeneity.Mycorrhizal plasticity has been least studied so far.Some researches revealed that mycorrhiza,rather than fine root,proliferated in enriched patches.But,it is not the case with other studies.The proliferation of mycorrhiza within enriched patches is more profitable in term of carbon invest.The effect of fine root proliferation on nutrient uptake is complex,depending on ion mobility and whether or not neighboring plant exists.The influence of root plasticity on the growth of plants is species specific.Some species (sensitive species) gain growth benefit,while others don't.The ability of an individual plant to response to heterogeneous resources has significant effect on its competitive ability and its fate within the community,and eventually shapes the composition and structure of the community.
    Formation of iron plaque on root surface and its effect on plant nutrition and ecological environment
    HE Chun'e, LIU Xuejun, ZHANG Fusuo
    2004, (6):  1069-1073. 
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    This paper illustrated the conditions of iron plaque formation on root surface,the morphology,mineralogical composition and deposition site of the plaque,and its function as a Fe reservoir in supplying Fe nutrient and affecting the uptake of other nutrients such as phosphorus and zinc.The environmental and ecological role of the plaque in inhibiting the uptake and translocation of heavy metals such as Cu,Ni,Cd and As through absorption or co-precipitation was called external tolerance mechanism,while its competition with heavy metals for metabolically sensitive sites in plants was called internal tolerance mechanisms.These two mechanisms help plant survive in high acidic and low carbon environment.
    Research advance in application of heat technique in studying stem sap flow
    SUN Huizhen, ZHOU Xiaofeng, KANG Shaozhong
    2004, (6):  1074-1078. 
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    This paper reviewed the principles of heat technique and its application in studying stem sap flow.Heat technique combined with determinations of tree physiological items such as whole-tree hydraulic conductance,stomatal conductance,water potential,and stem water storage can make us deeply analyze the regulation mechanism of tree transpiration,and approach the effect of environmental conditions on stem sap flow and its response.In addition,this technique can be also used for a long-term measurement of the hydrological characters of zonal forest stands,which will give a powerful technical support in properly assessing the hydrological effect of forest.
    Research advance in cyclic hydroxamic acids,main allelochemicals of Zea mays
    NIE Chengrong, LUO Shiming, ZENG Rensen, WANG Jianwu, HUANG Jinghua, LI Mei
    2004, (6):  1079-1082. 
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    The research advance in cyclic hydroxamic acids was reviewed in this paper.Cyclic hydroxamic acids are the important natural products of cereal crops.They and their respective derivatives are the constitutive compounds of a wide variety of gramineous plants and few dicot plants.They have structural diversity and different natural occurrences.Because of their phytotoxic properties,cyclic hydroxamic acids show a great variety of biological activities.They are the defensive agents against plant diseases,pests,nematodes and other plants.The distribution of cyclic hydroxamic acids in Zea mays and their variation in relation to the age were focused on in the paper.In Zea mays,there are structural diversity of cyclic hydroxamic acids and related benzoxazolinones.DIMBOA (1,4-benzoxazin-3(4H)-ones) is the most abundant derivative in Zea mays.The content of cyclic hydroxamic acids is strongly cultivar-dependent in Zea mays.Hydroxamic acids are not present in seeds.After germination,the level of DIMBOA increases,and the maximum level occurs in young seedlings a few days after germination.DIMBOA exists in all parts of plants,and its concentration is generally higher in shoots than in roots.In all stages,the young leaves of Zea mays have relatively high content of DIMBOA.The concentrations of these hydroxamic acids are highly dependent on environmental growth conditions.Under UV-light and water deficiencies,the levels of hydroxamic acids in plant increase rapidly.Cyclic hydroxamic acids exuded by Zea mays root can be quantitatively analyzed by HPLC.Supplying iron can significantly increase the exudation of DIMBOA from Zea mays root.
    Soil dissolved organic matter and its effect on chemical and biological behaviors of soil heavy metals
    LI Tingqiang, YANG Xiao'e
    2004, (6):  1083-1087. 
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    Dissolved organic matter (DOM) is an important and active component in both terrestrial and aquatic ecosystems,while soil DOM plays an important role in the pedogenesis,mineral weathering,and translocation of pollutants in soils.It has become a hotspot in environment science,soil science and ecology.Soil DOM has important effects on the chemical and biological behaviors of heavy metals in soil-plant system,but its mechanism is not identified.The study on soil DOM in China was still in its initial stages,and most studies only reported that the activity of heavy metals in soils was affected by the DOM produced from organic fertilizer.This review is to summarize the recent literatures regarding the formation of soil DOM and its affecting factors,and the effect of soil DOM on the chemical and biological behaviors of heavy metals in soils.The main affecting mechanisms of soil DOM on behaviors of soil heavy metals were summarized as complexing with heavy metals,competing with metals for adsorption sites,and affecting soil pH value.
    Research advance in characteristics of molybdenum,boron and selenium in red soils of South China and effects of their reasonable application on forage grass growth
    WENG Boqi, HUANG Dongfeng
    2004, (6):  1088-1094. 
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    Reasonable fertilization and fertility improvement of red soils are the important measures to develop the forage industry in hilly regions of South China.This paper summarized the existing form,chemical feature,availability and content of molybdenum,boron and selenium in red soils of South China.The lack of these three microelements in red soils was in common,and their reasonable application could significantly improve the growth of forage grass and its yield.The authors discussed the effects of molybdenum,boron and selenium application on the uptake and accumulation of available nutrients by forage grass and relevant physiological functions,described the molybdenum,boron and selenium deficiency symptoms of forage grass,their diagnostic methods and correcting measures,and put forward some suggestions for deepening the study.
    Mechanism of stomatal regulation by root sourced signaling and its agricultural significance
    GUO Anhong, LI Zhaoxiang, LIU Gengshan, YANG Yuanyan, AN Shunqing
    2004, (6):  1095-1099. 
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    Under soil drought condition,root sourced signal abscisic acid (ABA) plays an important role in the long distance signaling process,and can be a measurement of soil water availability.ABA is also an effective stomatal closing agent,and acts to reduce transpiration and canopy water loss.This paper briefly introduced the physiological mechanism and theoretical model about the stomatal regulation by root sourced signaling,and indicated that the combination of this model with root water absorption model and stomatal conductance model could be more effective in depicting the response of plant to soil drying and atmospheric drought.In addition,some effective irrigation approaches,such as regulated deficit irrigation (RDI),partial root-zone drying (PRD) and controlled alternative irrigation (CAI) were profited from the mechanism of plant water use regulation by the root sourced signaling.These irrigation measures favored to reasonably distribute available soil water in root zone.Root signaling system also played important role in regulating root growth and its development,retarding shoot growth to adjusting root shoot ratio,and optimizing assimilation allocation to favor to improve reproductive development.These processes hold substantial promise for enhancing crop water use efficiency.
    Antibiotics production by bacterial agents and its role in biological control
    WANG Guanghua, Jos M. Raaijmakers
    2004, (6):  1100-1104. 
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    Using bacteria to control plant diseases is one of the main strategies in plant protection,and its mechanism is commonly thought to be the production of antibiotics by bacteria.The produced antibiotics not only have structural diversity,but also have broad-spectrum activity against many pathogens.Experimental results showed that one kind of antibiotics could be produced by several bacterial strains,and one bacterial strain could also produced more than one kind of antibiotics.Recent development in molecular and bio-analytical techniques greatly promoted the research of bacterial bio-control,and the colonization survey of introducing bacterial strain to the rhizosphere and spermosphere of host plants.Besides bacterial genotypes,several biotic and abiotic factors including whether the pathogens existing or not,temperature,pH,carbon and nitrogen sources are also identified to affect the antibiotics production by bacteria.The authors illustrated some of the impeding problems in bacterial bio-control agents' application,and suggested that in the future research,more attention should be paid on developing mixed bio-control agent to avoid the anti-antibiotic activity of pathogens.
    Community characteristics in Hongchiba area of Wuxi County during ecological restoration after controlled burning
    HE Binghui, HAO Yunqing, LI Xuguang, HAN Chenxia, CHEN Changpei, ZHENG Guoci
    2004, (6):  1105-1108. 
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    This paper studied the species composition and the structure and species diversity of communities in Hongchiba area of Wuxi County after controlled burning and aerial sowing afforestation.The results showed that after burning and afforestation,pure Pinus armandii forest was not developed,but various mixed needle board-leaved forests which comprised P.armandii and native board-leaved trees grew.Various native species contributed to the communities with great species diversity.Shannon-Wiener index was 2.305～3.145,ecological dominance was 0.063～0.151,and evenness was 0.600～0.749 The natural regeneration of P.armandii population was very poor,and there was a trend that P.armandii would be gradually replaced by other native board-leaved trees.It was demonstrated that P.armandii should not be taken as a unique afforest tree,and controlled burning was not a favorite ecological measure in subtropical area.Native trees should play more important roles in the process of ecological restoration.
    Life table and spectral analysis of endangered plant Taxus chinensis var.mairei population
    HONG Wei, WANG Xingong, WU Chengzhen, HE Dongjin, LIAO Chengzhang, CHENG Yu, FENG Lei
    2004, (6):  1109-1112. 
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    Based on the investigation in Longxi Mountain National Nature Reserve and the theory of survival analysis,a static life table of Taxus chinensis var. mairei population was worked out,the curves of its survival rate,mortality rate and killing power were drawn,and the population dynamics was analyzed by spectral analysis.The results showed that the survival curve of the population appeared to be a type of Deevey-Ⅲ,and the high mortality of seeding was one of the important reasons which caused Taxus chinensis var. mairei to be endangered.The spectral analysis of the population showed that there was a marked periodic regularity in the process of natural regeneration of Taxus chinensis var. mairei.
    Niche characteristics of plant populations in Quercus aliena var. acuteserrata stands in Qinling Mountains
    ZHAO Yonghua, LEI Ruide, HE Xingyuan, JIA Xia
    2004, (6):  913-918. 
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    Based on the data collected from31 plots and using Levins,Hurlbert and Pianka formulas,this paper calculated and analyzed the niche breadths and overlaps of 24 tree and 29 shrub populations in Quercus aliena var. acuteserrata stands in Mt.Qinling,Shaanxi.The results showed that the Levins and Hurlbert's niche breadths of Quercus aliena var. acuteserrata,Pinus armandi,Toxicodendron vernicifluum,Populus davidiana and Pinus tabulaeformis in arbor layer were 3.695,1.695,1.325,0.840,0.702 and 0.036,0.299,0.568,1.721,2.701 respectively,and those of Corrylus heterophylla,Lespedeza formosa and Smilax vaginata in shrub layer were 1.833,1.466,0.984 and 0.111,0.300,0.594,respectively.In general,the niche overlaps between the species with bigger niche breadth and other species were higher,and those of the species having similar environmental requirements were also higher.
    Water conservation functions of several artificial forest ecosystems in semiarid region of western Liaoning Province
    LUO Yuechu, HAN Shanheng, WANG Hongchang, LIU Jianmin, WEI Jing, WU Gang
    2004, (6):  919-923. 
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    Five artificial forest ecosystems in semiarid region of western Liaoning Province were selected to test their water conservation capacity.The average interception rate of different artificial forest ecosystems varied from 14.58% to 37.19%,and the order was H.rhamnoides forest ecosystem> P.tabulaeformis-H.rhamnoides mixed forest ecosystem> P.simonii H.rhamnoides mixed forest ecosystem> P.tabulaeformis forest ecosystem> P.simonii forest ecosystem.The thickness of the litter layer in different forest ecosystems varied from 1.6 to 4.1 cm,and the biomass of the litter varied from 1 890.4 to 6 425.2 kg hm-2.The order of the thickness and the biomass of the litter in different forest ecosystems was H.rhamnoides forest ecosystem> P.tabulaeformis H.rhamnoides mixed forest ecosystem> P.simonii H.rhamnoides mixed forest ecosystem> P.tabulaeformis forest ecosystem> P.simonii forest ecosystem.The maximum water holding capacity of the litter in different forest ecosystems varied form 5 957.7 to 1 9332.9 kg·hm-2,and the order was H.rhamnoides forest ecosystem> P.tabulaeformis H.rhamnoides mixed forest ecosystem> P.simonii H.rhamnoides mixed forest ecosystem> P.tabulaeformis forest ecosystem> P.simonii forest ecosystem.The water holding capacity of non capillary porosity of 0～40 cm soil layer in different forest ecosystems varied from23.70 to 37.85 mm,and the order was H.rhamnoides forest ecosystem> P.simonii H.rhamnoides mixed forest ecosystem> P.tabulaeformis H.rhamnoides mixed forest ecosystem> P.simonii forest ecosystem> P.tabulaeformis forest ecosystem.Among the five artificial forest ecosystems, H.rhamnoides forest ecosystem had the best water conservation capacity,and the mixed forest ecosystems had a better water conservation capacity than P.tabulaeformis and P.simonii forest ecosystem.
    Dynamics and species-diversities of artificial Sonneratia apetala,Sonneratia caseolaris and Kandelia candel communities
    CHEN Yujun, LIAO Baowen, ZHENG Songfa, LI Mei, SONG Xiangyu
    2004, (6):  924-928. 
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    Studies on the dynamics and species diversities of artificial Sonneratia apetala,Sonneratia caseolaris and Kandelia candel communities showed that the arbor layer of S.apetala and S.caseolaris communities contained two distinctive sub layers.The upper layer was composed of S.apetala or S.caseolaris,and the medium layer was composed of K.candel and Aegiceras corniculatum.The dominant population S.apetala or S.caseolaris in S.apetala and S.caseolaris communities only had old aged individuals but no regenerations appeared recently,while K.candel and A.corniculatum were actively progressive populations,which would possibly become dominant populations during the course of community development,showing that S.apetala and S.caseolaris were pioneer species for plantation,which could promote natural colonization of regional mangrove species when planted at open mudflat. K.candel was the actively progressive population in K.candel community,its natural regeneration and succession could be successful,while A.corniculatum and B.sexangula were initially progressive populations.The species composition and species diversities of S.apetala and S.caseolaris communities were similar,both contained the main species in K.candel community,namely, K.candel,A.corniculatum and Bruguiera sexangula,showing that S.apetala and S.caseolaris could co exist with these regional species.To introduce and plant them could help to form complicated and diversified mangrove communities.During the early stage of the development,the species diversities of S.apetala and S.caseolaris communities were higher when their planting density was high.The species diversities grew slightly higher when the communities became older.
    Radiation characteristics in a tropical seasonal rain forest canopy gap
    ZHANG Yiping, DOU Junxia, LIU Yuhong, MA Youxin
    2004, (6):  929-934. 
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    Based on the observation on the radiation with different wavelengths in tropical seasonal rain forest canopy gap,interior of forest,and meteorological station in different seasons,the radiation characteristics of canopy gap were discussed.The results showed that the value of different wavelength radiation had the phenomenon of "suddenly emergent" at the center and north edge of canopy gap.Moreover,each radiation value reached the maximum rapidly,and then decreased quickly around the noon.The daily gross radiation of different wavelengths within the canopy gap was bigger than that in the interior of forest,but smaller than that at meteorological station.Compared to the north edge,the daily gross radiation in the center of the gap was bigger in dry hot season,rain season and later rain season,but smaller in fog cool season,which was influenced by dense fog,solar angle and azimuth.The total daily gross solar radiation at the center was the maximum when the solar angle was the biggest in rain season,higher in later rain season and dry hot season,and was the minimum in fog cool season.The ratios of infrared and visible light radiation to total solar radiation varied with the seasons at the center and north edge of the canopy gap,which fully indicated the environmental heterogeneity within the canopy gap.Compared with meteorological station and interior of forest,the ratios of infrared radiation to total solar radiation in the gap were bigger than those of meteorological station,but smaller than those of interior of forest,which were just contrary to the ratios of visible light to total solar radiation.In addition,the seasonal variation of the ratios of visible light to total solar radiation was higher than that of the ratios of infrared radiation to total solar radiation within the gap.Generally,canopy gap could increase infrared radiation and decrease visible light radiation in tropical seasonal rain forest.
    Effect of phosphorus stress on chlorophyll biosynthesis,photosynthesis and biomass partitioning pattern of Fraxinus mandchurica seedlings
    WU Chu, FAN Zhiqiang, WANG Zhengquan
    2004, (6):  935-940. 
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    Phosphorus is essential to forest trees for their growth and development,because of its important role in many metabolic processes of trees.But,most part of phosphorus in soils of Northeastern China is immobile and unavailable,and thus,many forest trees often suffer from phosphorus stress which affects the biomass accumulation of forest trees.The aim of this study is to understand how the chlorophyll biosynthesis,photosynthesis and biomass partitioning of Fraxinus mandchurica seedlings response to phosphorus stress.Sand culture experiment showed that when the seedlings were under phosphorus stress,their 5 aminolevulinic acid (ALA) biosynthesis rate and porphobilinogen (PBG) synthase activity were reduced,but no significant changes in chlorophyll a and b,total chlorophyll and carotenoid contents were found.The nitrogen content in leaves and roots and the phosphorus content in all parts of seedlings were reduced under phosphorus stress,and the reduction of N content in leaves induced the decrease of maximum quantum efficiency of PSⅡ (Fv/Fm)efficiency of PSⅡ photochemistry (ΦPSⅡ),electron transport rate (ETR),and maximum photosynthesis rate(Amax).The effect of phosphorus stress on chlorophyll biosynthesis didn't affect photosynthesis.Under phosphorus stress,the total biomass decreased,but more biomass was partitioned into roots.
    Snow/wind damage in natural secondary forests in Liaodong mountainous regions of Liaoning Province
    LI Xiufen, ZHU Jiaojun, WANG Qingli, LIU Zugen, HOU Chuansheng, YANG Huanjun
    2004, (6):  941-946. 
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    In early spring of 2003,the secondary forests at the Qingyuan Experimental Forests (QEF) of the Institute of Applied Ecology,Chinese Academy of Sciences suffered from the damage caused by snow and wind (snow/wind damage).This damage occurred at 800 m above sea level was the most serious one since 1949 In order to make clear its occurrence and process and to analyze its possible influences on the secondary forest system,comprehensive investigations were conducted soon after the snow/wind damage.The results showed that the occurrence of this damage was due to the special site conditions (higher sea level and steeper slopes) and air temperature,which suited the wet snow formation and the snow accumulation on trees after a large scale of precipitation.The more seriously damaged areas were those with the stands of Acer mono,Juglans mandshurica,Populus spp. and so on.The ratio of damaged trees was negatively correlated with stand density,soil depth and size class of diameter,and positively correlated with tree height.Based on these results,the likely influences of snow/wind damage,i.e.,the happening of diseases and insect pests,the vegetation changing under forests,and the factors of habitat and dominant species in natural secondary forests were also discussed.It is significant that to do observation and basic research on damaged forests will provide reasonable strategies for management of natural secondary forests.
    Spatial pattern of two dominant shrub populations at transitional zone between oasis and desert of Heihe River Basin
    HE Zhibin, ZHAO Wenzhi
    2004, (6):  947-952. 
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    Based on the field investigation in a 500 m×500 m plot and applying geo statistical theory and methods,this paper described the spatial pattern of the coverage,density,height and volume of two shrub populations Nitraria sphaerocarpa and Reaumuria soongorica at the transitional zone between oasis and desert of Heihe River Basin.The average coverage of the two populations was 1.56±2.34% and 0.23±0.22%,and their average density was 1.5±1.8 clump·100 m-2 and 2.3±2.1 individual·100 m-2,respectively.The height of N. sphaerocarpa was 0.18±0.15 m,and its volume 0.10±0.18 m3. N. sphaerocarpa population exhibited strip distribution pattern,while R. soongorica population showed uniform distribution pattern.The nugget (c0) /sill (c0+c) ratio of the semivariogram of the two populations was 0.08～0.12,which indicates that the random variance of spatial heterogeneity occupied 8%～12%.In semivariogram model,the range value (A0) of the coverage and density was 14.7 and 33.9 m for N. sphaerocarpa,and 25.2 m and 24.9 m for R. soongorica,respectively.As a whole,the random spatial heterogeneity existed at the scale of 10m,and autocorrelated spatial heterogeneity existed at the scale of 34 m.The spatial heterogeneity of the coverage and density of the two dominant populations showed both isotropy and anisotropy,and the isotropy scope of R.soongorica population was larger than that of N.sphaerocarpa.The spatial pattern of N. sphaerocarpa population was controlled by two factors.The first was precipitation and surface runoff,and the second was oasisofication and desertification.
    Effect of land use change on spatial distribution pattern of soil total nitrogen in Keerqin sandy land
    CHEN Fusheng, ZENG Dehui, CHEN Guangsheng
    2004, (6):  953-957. 
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    By using statistics and geostatistics,this paper studied the content and spatial pattern of soil total nitrogen (TN) in a glassland and an arable land of southeast Keerqin sandy land.The TN content in 0～10 cm soil layer of the arable land reclaimed from a glassland 8 years ago was not different from that of the virgin grassland,but the TN content in 10～20 cm soil layer was higher than that in the grassland (P <0.05).The soil TN storage in the grassland was 262.36 g·hm-2 higher than that in the arable land,and its spatial pattern was significantly different between arable land and grassland.The heterogeneity and spatial dependence of TN in each soil layer (0～10 cm and 10～20 cm) of the arable land were larger than those of the grassland,and the ranges and fractal dimensions of TN in each soil layer of the arable land were larger than those of the grassland.There existed a clear horizontal spatial structure heterogeneity and spatial distribution pattern in the arable land,while in the grassland,the horizontal spatial structure heterogeneity was very low,and the horizontal spatial distribution pattern was random and uniform.The TN content in the 0～10 cm and 10～20 cm soil layers of the arable land had no difference (P <0.05),its spatial structure characters had some difference (P <0.05),and its spatial distribution pattern was very similar (r=0.683,P <0.05).The TN content and its spatial structure characters between two soil layers of the grassland had remarkable difference (P <0.05),but its spatial distribution pattern in the two layers was relatively similar (r=0.395,P <0.05).In conclusion,agricultural activity could not only influence soil TN content,but also influence its spatial structure characteristics and spatial distribution pattern.Therefore,our study might promote the further study on the effect of land use change on soil nitrogen distribution pattern and its cycling in ecosystems.
    Effect of cone-picking on natural regeneration of Korean pine in Changbai Mountain Nature Reserve
    LIU Zugen, JI Lanzhu, HAO Zhanqing, ZHU Jiaojun, KANG Hongzhang
    2004, (6):  958-962. 
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    The storage and distribution of Korean pine seeds on Korean pine forest floor in Changbai Mountain Nature Reserve were investigated,and the data were compared with those in 1970s when the forest was little disturbed.Based on the dependence of natural regeneration of Korean pine on seed predating animals,the effect of commercial cone picking on natural regeneration of Korean pine was discussed.The results showed that Korean pine seeds were generally berried under litter layer,and most of them were dropped during cone picking.The density of Korean pine seeds was 1 582～2 640·hm-2,accounted for 0.3%～0.5% of that in 1970s.Furthermore,over 67.8% of these seeds were rotten.Unlike the seeds distributed by squirrel,many (46.7%～77.1%) of them distributed singly.Animals that pick seeds from cone and thus are important for natural regeneration of Korean pine have reduced their population or even disappeared in recent years because most Korean pine cone were collected by people.Therefore,cone picking was one of the obstacles for natural regeneration of Korean pine in Changbai Mountain Nature Reserve.
    Community structure organization and its relation with environmental factors of sown grassland in South China
    XIN Xiaoping, Wang Zongli, YANG Guixia, LI Xianglin
    2004, (6):  963-968. 
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    Contribution of environmental factors,spatial factors,biological and random factors to community structure within a man made grassland in southern terra was partitioned using canonical correspondence analysis.Under mowing and grazing,environmental factors explained (27.4% and 25.9%) variation of community structure.Contribution of spatial factors was 32.5%,24.2%,respectively.Contribution of biological and random factors was 48% and 56%,respectively.Gradient in community structure and species abundance is evident along environmental gradient in mowing grassland.The environment community/species relations were more complex in grazed grassland.Patches under different grazing intensity develop toward different directions.
    Amelioration of secondary bare alkali-saline patches in Songnen Plain through inserting cornstalk.
    HE Nianpeng, WU Ling, JIANG Shicheng, ZHOU Daowei
    2004, (6):  969-972. 
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    Based on the field experiment on Songnen grassland,a new method was established to ameliorate the secondary bare alkali saline patches (SAP) through inserting cornstalk.The experiment was rested on the assumption that through inserting cornstalk in the secondary bare alkali saline patches (SAP) to retain seeds moving over its surface,the necessary seed source could be gained; and these seeds should be able to germinate and survive successfully on the cornstalk itself or in its neighborhood,where should be more fit to grow than other sites in SAP,due to the decomposition of cornstalk and its special role,so that,the aim to restore vegetation of SAP could be achieved at a pretty low cost and rapid speed.The results showed that the seed bank in soil was increased significantly,owing to the inserted cornstalk and its operating processes.The seed number in ameliorated soil was 4 020.0 ?1 773.6 seeds穖-2,while that in the secondary bare alkali saline patches (SAP) was only 10.0?31.6 seeds穖-2.Although the soil chemical and physical characters in ameliorated zone were improved to some extent,the overall situation of soil was still bad for plant growth,as the pH,soluble saline ion and organic matter were concerned.Most of Chloris virgata grew around or on the cornstalk,the plants around each cornstalk being 3.9?2.2,and the total being 48.64?38.72 g穖-2.Therefore,this method demanded a few resources,and needed simple technology and low cost,which is potentially deserved to popularize.
    Consistency between neutral landscape models and real landscape
    WANG Xugao, LI Xiuzhen, HE Hongshi, HU Yuanman
    2004, (6):  973-978. 
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    Neutral landscape models (NLM) can provide standards against real landscapes,and are used to describe landscape pattern and process in the past few decades.In this paper,the neutral landscape models RULE and SimMap were tested against a real landscape,and a set of landscape metrics were used to quantify the spatial characteristics of real and simulated patterns.Measurements of some metrics (total number of patches,total perimeter,average patch area,aggregation index,contagion and lacunarity) suggested that definite level of consistency between NLM generated maps and real landscape did exist at landscape or class levels.But,there were also some metrics,such as corrected patch perimeter area ratio,fractal double logged and edge distribution evenness,which didn't show any agreement between the generated maps and real landscape.In all,each NLM had its own strength in representing real landscape,but none of them was perfect.
    Effect of soil preparation and fertilization on foliage and shoot growth of Ginkgo biloba and its medicine content
    HE Binghui, ZHONG Zhangcheng
    2004, (6):  979-982. 
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    The study showed that the efficiency of various treatments in improving the height growth of Ginkgo biloba was organic fertilizer plus intercropping>soil preparation by blasting plus intercropping>organic fertilizer>soil preparation by blasting>intercropping,and the height growth increased by 14.5%,8.6%,5.7%,3.2% and 0,respectively.The efficiency of the treatments in improving new shoot growth was organic fertilizer plus intercropping>soil preparation by blasting plus intercropping>intercropping>organic fertilizer>soil preparation by blasting,and the new shoot growth increased by 58.1%,36.6%,33.1%,30.2% and 14.0%,respectively.Soil preparation,organic fertilization and intercropping had no different effect on the number of long shoots,but their effect on the numbers of short shoots and leaves was significantly different.The most efficient treatment in improving the medicine content was organic fertilization plus intercropping.Compared with control,the content of quercetin and rutin in Ginkgo biloba leaves increased by 420% and 220%,respectively.
    Nitrogen use efficiency and its relationship with nitrogen nutrition characteristics of wheat varieties
    SUN Chuanfan, DAI Tingbo, JING Qi, JIANG Dong, CAO Weixing
    2004, (6):  983-987. 
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    Forty wheat varieties were tested at two sites (Xuzhou and Nanjing) to evaluate genotypic and environmental variation of nitrogen use efficiency (NUE) and its relationship with nitrogen nutrition characteristics.It was shown that genotype had significant effect on NUE,but environment had less effect on NRE and NFE.All of the nitrogen nutrition traits were significantly influenced by the interaction of genotype譭nvironment.NFE,as an integrated index reflecting the differences of grain yield and nitrogen utilization among different wheat varieties,was significantly correlated with NRE,NPP and NPS,which indicated that it should be more useful in evaluating nitrogen use efficiency.NFE could be improved by increasing N assimilation and translocation after anthesis to effectively increase the N utilization of wheat.
    Soil arthropod communities in different successional tropical secondary forests in Xishuangbanna,SW China
    YANG Xiaodong, TANG Jianwei
    2004, (6):  988-994. 
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    Studies on the soil arthropod community structure and its seasonal variation in four types of secondary forest,including Macaranga denticulate forest(Md), Millettia laptobotrya forest(Ml), Musa acuminata forest(Ma)and Dendrocalamus membranaceae forest(Dm)in Xishuangbanna showed that Acari,Hymenoptera(ant)and Collembola were the dominant groups of soil arthropods on all study sites,but their proportions differed in different forests.For the common and rare groups of soil arthropods,there were some differences in four forests.We found fewer taxonomic groups(number of order),individuals and DG diversity index of soil arthropod communities in Dm secondary forest,as compared to another three forest types.There was no significant difference in number of groups and individuals and DG diversity index of soil arthropods among Md,Ml and Ma.The taxonomic diversity and population of soil arthropods were higher in top soil(0～5 cm)than in deeper layers.The research indicated that the dynamics of soil arthropods was correlated with the fluctuation of temperature and rainfall in this area.In general,the groups,populations and DG diversity index of soil arthropod communities were higher in dry season or early rainy season than in middle rainy season.There were some differences in the seasonal variation of soil arthropod communities in different type forests,which was primarily related to precipitation,temperature,litter quantity and quality,and biology of different soil arthropods.Apparently,food,habitation and disturb also have effects on the seasonal variation of soil arthropod communities in different forests.
    Food nourishment utilization efficiency of different month aged sheep
    WANG Qin, REN Jizhou, WANG Xiaolan, XIA Hong, JIN Lingmei
    2004, (6):  995-999. 
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    Studies on the food nourishment utilization efficiency of different month aged sheep showed that under same food nourishment condition,the ingested nourishment,weight increase,and nourishment depletion per unit weight increase of sheep were increased with the ingestion of dry matter,and the protein content of 34 months old sheep was significantly higher than that of 22 months old sheep (P <0.01),and the latter was significantly higher than that of 10 months old sheep (P <0.01).There was a significant difference of utilization efficiency of the ingested nourishment between 34 months old and 22 months old sheep (P <0.05) and between 10 months old and 22 months old sheep (P <0.01).The weight increase was not significantly different (P >0.05) between 34 months old and 22 months old sheep and between 10 months old and 22 months old sheep,but it was significantly different between 34 months old and 10 months old sheep (P <0.05).The feed conversion rate among them was not different.All the results showed that 10～22 months old sheep had high production efficiency,and could produce high quality mutton,and hence,this section of age was the suitable age of sheep to be butchered.
    Effect of fertilization on soil enzymes and microbes in Larix gemlinii plantations
    CHEN Lixin
    2004, (6):  1000-1004. 
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    One year-old second generation stand and 14 year-and 34 year-old first generation stands in larch plantations were studied at the Maoershan Mt. Experimental Forest Farm. The forestland of these three stands was treated with various fertilizations. The results showed that fertilization could promote or restrain soil enzyme activity and microbial amount with different degrees, and its effect on soil physiological activity was more apparent. The effect of the same fertilisation treatmenu on soil enzyme activity and microbial amount was different at different development stages of the stands. For one year-old stand, the best fertilization scheme was treatment 9, its soil enzyme activities (catalase, proteinase, polyphenoloxidase,urease，and saccharase), total microbial amount, and amount of bacteria, actinomyces and fungus being increased by 413.49%,22.10%，20. 56%，220. 00%，49. 46 %，238. 88 %，247. 24 %,106. 70 %，and 366 . 67 %,respectively, as compared with the mntrol. For 34 year-old stand, the best fertilization scheme was treatment 5, its soil enzyme activities(catalase, proteinase,polyphenoloxidase,urease，and saccharase), total microbial amount, and amount of bacteria and fungus was increased by 30. 44 %，16.91%,0.22%,43.06%，124.18 %，119. 92 %, 87 . 66 %, and 17. 57&，respectively in rhizosphere soil, and by 24 . 55 %，77. 0l %，168.62 %，251. 85 %，183. 33 %, 250. 0 %，38 . 24 % and 128 . 57 %，respectively in non-rhizosphere soil. For 14 year-old young stand, it needed a proper amount of nitrogen fertilizer and organic-mineral fertilizers, and the better fertilisation schemes were treatments 2 and 9. The soil enzyme activities (catslose, proteinase, and，urease)in treatment 2 was increased by 44. 39 %, 94 . 83 %，and 4 . 62 %，respectively in rhizcsphere soil, and by 13 . 98 %，10. 70 % and 129 . 76 %，respectively in non-rhizosphere soil. Total soil microbial amount and the amount of bacteria and fungus in treatment 9 was increased by 176. 49 %, 266. 63&, and 198. 04 %, respectively in rhizcsphere Broil, and by 275 . 56 %, 66. 67 % and 143 . 75 %，respectively in non-rhizasphere soil.
    Variation of microflora and enzyme activity in continuous cropping cucumber soil in solar greenhouse
    MA Yunhua, WEI Min, WANG Xiufeng
    2004, (6):  1005-1008. 
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    Variation of microflora and enzyme activity in solar greenhouse soil continuous cropping for 1,3,5,7,9 years was studied,in addition to the relationship between soil properities and microflora and enzyme activity.The results showed that number of bacteria,actinomyce as well as total microflora showed a trend with a saddle-shaped curve,while the number of fungi appeared an liner increase.Continuous cropping soil microflora shifed from bacteria type to fungi type significiently,of which Ammoniation bacterium and Fusarium oxysporum were main physiology groups.Path analysis results showed that microelements(Mn,Cu,Fe),organic matter,available N and bulk density are main restricted factors of soil microflora and enzyme activity in solar greenhouse.
    Effect of sodium phytate on alkaline phosphatase (ALP) activity in intraradical hyphae of AM fungi and development of its extraradical hyphae
    FENG Haiyan, FENG Gu, WANG Jingguo, LI Xiaolin
    2004, (6):  1009-1013. 
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    In this paper,a pot experiment with three compartments was installed to study the effect of Na-phytate on the development and metabolic activity of AM fungi.Maize was selected as host plant and inoculated with arbuscular mycorrhizal fungus (Glomus intraradices),and different amounts of Na-phytate were applied into hyphal compartments.The results showed that the absorbed P in the shoots and roots of maize inoculated with AM fungi was 1～2 times higher than that of non inoculated maize.The ALP activity in intraradical hyphae of AM fungi was significantly decreased,and the total hyphal density of AM fungi increased with applied Na-phytate.Observations suggested that the ALP activity in intraradical hyphae of AM fungi and the development of its extraradical hyphae could be regulated by Na-phytate.Additionally,AM fungi could enhance the plant's P absorption and utilization from native soil P and additive Na-phytate.
    Response of soil hydrolase and oxidoreductase activities to free-air carbon dioxide enrichment(FACE)under rice-wheat rotation
    ZHANG Yulan, ZHANG Lili, CHEN Lijun, WU Zhijie
    2004, (6):  1014-1018. 
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    This paper studied the response of soil urease,phosphatase,arylsulphatase and dehydrogenase to 200 μmol·mol-1 CO2 elevation under rice-wheat rotation.The results showed that under CO2 elevation,the urease activity in 0～10 cm soil layer was decreased at the early growth stages of wheat but increased at its booting stage;the activity increased at the early growth stages of rice but decreased at its ripening stage.Phosphatase activity was increased during the whole growth period of wheat;the activity increased at the tillering stage of rice but decreased at its later growth stages.Arylsulphatase activity was decreased at the over-wintering and booting stages of wheat but increased at its tillering and ripening stages.Dehydrogenase activity was decreased at the early growth stages of wheat and rice,but increased at their late growth stages.
    Response of soil saccharidase activities to free-air carbon dioxide enrichment (FACE) under rice-wheat rotation
    ZHANG Lili, ZHANG Yulan, CHEN Lijun, WU Zhijie
    2004, (6):  1019-1024. 
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    This paper studied the effect of 200 μmol·mol-1 CO2 elevation on soil saccharidase activities and soil nutrient contents under rice wheat rotation.The results showed that under both wheat and rice planting,CO2 elevation increased soil invertase activity.The elevated CO2 significantly increased soil xylanase activity at the jointing,heading and ripening stages of wheat and at the heading and ripening stages of rice,and slightly decreased soil cellulase activity.Correlation analysis showed that there was a significantly linear positive relationship between soil alkali hydrolyzed nitrogen and soil invertase activity.
    Vertical fractionation of dissolved organic matter in soil profile under water-dry cultivation
    ZHAN Xinhua, CUI Chunhong, LU Yanyu, ZHOU Lixiang
    2004, (6):  1025-1029. 
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    Dissolved organic matter (DOM) is the most active component of organic matters,and plays an important role in the translocation and transformation of pollutants and nutrients in terrestrial ecosystem.In this paper,the vertical fractionation of DOM in a yellow brown soil under water-dry cultivation was investigated by field experiment and physico-chemical analyses.The results showed that in treatments CK,chemical fertilizer and sewage sludge,the DOM concentration decreased from 145.8,117.7 and 114.8 mg穔g-1 to 21.57,23.23 and 13.78 mg穔g-1 with soil depth,respectively.In control and fertilizer-treated soils,the hydrophilic fraction of DOM was increased respectively from 19.01% and 18.47% to 34.97% and 44.37% with soil depth,and the biodegradable rate of DOM also increased with soil depth.In sludge-treated soil,a reverse tendency was found for the concentration of hydrophilic DOM and its biodegradable rate.Hydrophilic fraction decreased from 36.96% to 17.07%,the increase of hydrophobic fraction was from 63.04% to 82.93%,and the biodegradable rate decreased from 53.19% to 30.75% with soil depth.The biodegradable rate of DOM was positively correlated to the hydrophilic fraction of DOM,and UV spectra analysis also suggested this.
    Bacteria ecology in planting-culturing system
    HUANG Fenglian, XIA Beicheng, DAI Xin, CHEN Guizhu
    2004, (6):  1030-1034. 
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    ng system in inter tidal zone is a new type eco-culturing model.The survey on bacteria biomass and water quality in the designed planting culturing system in inter-tidal zone showed that the mangrove planted in the system improved water quality and made water quality to Ⅱ～Ⅲ type,better than the Ⅳ and Ⅴ type in the control pond.Designed ponds made heterotrophic bacteria,vibrio,phosphorus bacteria and enzyme-producing bacteria populations 1～2 order lower than the control pond without mongrove planting.Correlation analyses with CORREL software showed that the biomass of these bacteria was positively related with the nitrogen and phosphorus contents in water of the system,and the correlation coefficient for heterogeneous bacteria and vibrio was up to 0.9205.Heterotrophic bacteria and vibrio could be used as the water-quality monitoring organisms.
    Effect of temperature on Macrosiphoniella sanborni development
    DUAN Jinhua, ZHANG Runjie
    2004, (6):  1035-1038. 
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    The development of Macrosiphoniella sanborni was studied at 15～35 ℃ and 80% RH,and the data obtained were used to determine the rate and threshold of its development and the sum of effective temperature.The optimal temperature for M.sanborni development ranged from 22 ℃ to 25 ℃.After fitting the data to Wang Rusong's model,the development rate V(t) increased with rising temperature.The 2nd and 3rd instar nymphs were found more tolerable to extreme temperature and had higher optimal temperature than 1st and 4th instar nymphs.The temperature tolerance value δ was 6.70 for the 2nd and 3rd instars,and 4.70 and 4.50 for the 1st and 4th instars,respectively. The optimal temperature for the 2nd and 3rd instar was 21.76 ℃,and the highest development temperature was 40.97 ℃,while for the 1st and 4th instar,the optimal temperature was 23.76 ℃ and 22.49 ℃,and the highest development temperature was 39.97 ℃ and 40 56 ℃,respectively.Calculations with direct optimum estimation method showed that the threshold of development decreased with the aging of nymphs,while the effective accumulative temperature increased.For the 1st,2nd,3rd and 4th instar,the threshold of development was 6.93,5.02,4.58 and 4.46 ℃,and the effective accumulative temperature was 26.88,33.41,33.63 and 48.49 ℃·d-1,respectively.
    Spatial structure of populations Myzus persicae and its predatory natural enemy Erigonidium graminicola
    WU Houzhang, XU Guangshu, FANG Minghui, CHENG Xianian, ZOU Yunding
    2004, (6):  1039-1042. 
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    In this paper,the spatial construction models of populations M. persicae and its predatory natural enemy E. graminicola during different periods were simulated by geostatistics,and their spatial relationships were analyzed.The spatial structure of M. persicae population was described by spherical model,showing an aggregated spatial arrangement.Its spatial dependence was 2.0252～4.1495 m,heterogeneity degree was 10 281.36～ 300 216.30, and sample variance was 12 176.81～303 433.70.The spatial structure of E. graminicola population was also simulated by spherical model,showing an aggregated spatial arrangement.Its spatial dependence was 3.7328～4.8983 m,heterogeneity degree was 1.4482～4.4134,and sample variance was 1.6941～5.8167.The results and methods could be applied to monitor the temporal and spatial dynamics of target insect pest population in tobacco field,and provide scientific basis for ecological control.
    Geostatistic analysis on spatial patterns of Aphis gossypii and Erigonidium graminicola
    LI Lei, ZOU Yunding, BI Shoudong, GAO Caiqiu, DING Chengcheng, MENG Qinglei, LI Changgen, ZHOU Xiazhi
    2004, (6):  1043-1046. 
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    The spatial structure and spatial correlativity of Aphis gossypii and Erigonidium graminicola populations during different periods were investigated by geostatistic methods.The results showed that the semivariogram of A.gossypii appeared as spherical type,indicating its spatial pattern was an aggregated type with a range of 7.33～12.40 cm,while that of E.graminicola was also fitted into spherical model,indicating an aggregated spatial arrangement with a range of 6.47～20.88 cm.The amount and spatial distribution of E.graminicola were closely related to those of A.gossypii,suggesting that E.graminicola was the dominant natural enemy influencing A.gossypii population.
    Emergy evaluation of power plant eco-industrial park
    WANG Lingmei, ZHANG Jintun
    2004, (6):  1047-1050. 
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    In this paper,new emergy indices for the material circulation utilization and energy cascade utilization were presented to evaluate the emergy of power plant eco industrial park.The common contribution of the members in power plant eco industrial park should be accounted for emergy yield ratio (PEYR) and emergy investment ratio (PEIR),namely, PEYR= (Fi+Ri+Ni)/ Fi and PEIR= Fi/ (Ni+Ri).Saved renewable and nonrenewable resources and purchased resources and decreased environmental load should be accounted for environmental loading ratio (PELR) and index of sustainability (PESI),namely, PELR= Fi/F' and PESI=PEYR/PELR.Case analysis on the Shuozhou power plant eco industrial park showed that new emergy indices were practical in evaluating the power plant eco-industrial park.
    Concept and methodology on up-scaling issue of small watershed prototypes for reconstructing ecological economies in Loess Plateau
    CHENG Xu, LIU Guobin, CHEN Youqi, CHANG Xin
    2004, (6):  1051-1055. 
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    The general ecological situation of Loess Plateau is kept deteriorating,despite great efforts have been made and some achievements were gained after 50 years' endeavor to control soil erosion and renovate ecological landscape.Investigations on the past 20 years results from 11 experimental sites showed that the extension of prototypes and models derived from these sites,which were all based on one scale of small watershed,were unsatisfactory.The possible reasons for such a situation could be attributed to the too coarse scale of map,on which,the regional planning were set up and the locations of these experiment sites were decided,the too fine scale of the small watershed which were usually 3～10 km2 in size,the shortage of studies on various scales particularly on the meso-scale,and the lack of methods of scaling on up-scaling.Based on the analysis of restraints in management of small watershed,the specific concept and relevant proposed methods of resemblance-scaling and multi-scale complementarity were put forward and tested.
    Sensitivity analysis in ecological modeling
    XU Chonggang, HU Yuanman, CHANG Yu, JIANG Yan, LI Xiuzhen, BU Renchang, HE Hongshi
    2004, (6):  1056-1062. 
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    Sensitivity analysis is used to qualitatively or quantitatively apportion the variation of model output to different source of variation.It is a very useful tool in model parameterization and calibration,and has important ecological significance by identifying the governing factors for a certain ecological process simulated.There are two schools of sensitivity analysis, local sensitivity analysis and global sensitivity analysis.The former examines the local response of the output(s) by varying input parameters one at a time,holding other parameters to a central value; and the latter examines the global response (averaged over the variation of all the parameters) of model output(s) by exploring a finite (or even an infinite) region.Since it is very easy to conduct local sensitivity analysis,it is very popular in ecological models.However,local sensitivity analysis is not computationally effective,because it can only get the sensitivity of a single parameter at a time.It can not take into consideration the effect of interaction of different parameters.Additionally,the value of other parameters will affect the sensitivity of the parameter specified.In view of this,global sensitivity analysis is increasingly preferred to local sensitivity in recent years.However,for most of the ecological modeling study published in Chinese,only local sensitivity analysis is conducted.To provide a toolbox of alternative sensitivity analysis algorithms for ecological model development in future study,we reviewed the main methods of both local sensitivity analysis and global sensitivity analysis,including one at a time method,multivariate regression,Morris' method,Sobol's method,Fourier Amplitude Sensitivity Analysis,and Extended Fourier Amplitude Sensitivity Analysis.Based on the state-of-the-art research on sensitivity analysis,the sensitivity of the interaction between two or more than two model parameters,the sensitivity of common model parameters in a set of models,and the sensitivity analysis in spatially explicit landscape model simulation were identified as the key areas and difficulties of future study on sensitivity analysis in ecological modeling.
    Response of fine roots to soil nutrient spatial heterogeneity
    WANG Qingcheng, CHENG Yunhuan
    2004, (6):  1063-1068. 
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    The spatial heterogeneity is the complexity and variation of systems or their attributes,and the heterogeneity of soil nutrients is ubiquitous in all natural ecosystems.The scale of spatial heterogeneity varies considerably among different ecosystems,from tens of centimeters to hundred meters.Some of the scales can be detected by individual plant.Because the growth of individual plants can be strongly influenced by soil heterogeneity,it follows that the inter specific competition should also be affected.During the long process of evolution,plants developed various plastic responses with their root system,including morphological,physiological and mycorrhizal plasticity,to maximize the nutrient acquisition from heterogeneous soil resources.Morphological plasticity,an adjustment in root system spatial allocation and architecture in response to spatial heterogeneous distribution of available soil resources,has been most intensively studied,and root proliferation in nutrient rich patches has been certified for many species.The species that do response may have an increased rate of nutrient uptake,leading to a competitive advantage.Scale and precision are two important features employed in describing the size and foraging behavior of root system.It was hypothesized that scale and precision is negatively related,i.e.,the species with high scale of root system tend to be a less precise forager.The outcomes of different research work have been diverse,far from reaching a consensus.Species with high scale are not necessarily less precise in fine root allocation,and vice versa.The proliferation of fine root in enriched micro-sites is species dependent,and also affected by other factors,such as patch attributes (size and nutrients concentration),nutrients,and overall soil fertility.Beside root proliferation in nutrient enriched patches,plants can also adapt themselves to the heterogeneous soil environment by altering other root characteristics such as fine root diameter,branch angle,length,and spatial architecture of root system.Physiological and mycorrhizal plasticity can add some influence on the morphological plasticity to some extent,but they are less studied.Roots located in different patches can quickly regulate their nutrient uptake kinetics within different nutrient patches,and increase overall nutrient uptake.Physiological response may,to certain extent,reduce morphological response,and is meaningful for plant growth on soils with frequently changing spatial and temporal heterogeneity.Mycorrhizal plasticity has been least studied so far.Some researches revealed that mycorrhiza,rather than fine root,proliferated in enriched patches.But,it is not the case with other studies.The proliferation of mycorrhiza within enriched patches is more profitable in term of carbon invest.The effect of fine root proliferation on nutrient uptake is complex,depending on ion mobility and whether or not neighboring plant exists.The influence of root plasticity on the growth of plants is species specific.Some species (sensitive species) gain growth benefit,while others don't.The ability of an individual plant to response to heterogeneous resources has significant effect on its competitive ability and its fate within the community,and eventually shapes the composition and structure of the community.
    Formation of iron plaque on root surface and its effect on plant nutrition and ecological environment
    HE Chun'e, LIU Xuejun, ZHANG Fusuo
    2004, (6):  1069-1073. 
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    This paper illustrated the conditions of iron plaque formation on root surface,the morphology,mineralogical composition and deposition site of the plaque,and its function as a Fe reservoir in supplying Fe nutrient and affecting the uptake of other nutrients such as phosphorus and zinc.The environmental and ecological role of the plaque in inhibiting the uptake and translocation of heavy metals such as Cu,Ni,Cd and As through absorption or co-precipitation was called external tolerance mechanism,while its competition with heavy metals for metabolically sensitive sites in plants was called internal tolerance mechanisms.These two mechanisms help plant survive in high acidic and low carbon environment.
    Research advance in application of heat technique in studying stem sap flow
    SUN Huizhen, ZHOU Xiaofeng, KANG Shaozhong
    2004, (6):  1074-1078. 
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    This paper reviewed the principles of heat technique and its application in studying stem sap flow.Heat technique combined with determinations of tree physiological items such as whole-tree hydraulic conductance,stomatal conductance,water potential,and stem water storage can make us deeply analyze the regulation mechanism of tree transpiration,and approach the effect of environmental conditions on stem sap flow and its response.In addition,this technique can be also used for a long-term measurement of the hydrological characters of zonal forest stands,which will give a powerful technical support in properly assessing the hydrological effect of forest.
    Research advance in cyclic hydroxamic acids,main allelochemicals of Zea mays
    NIE Chengrong, LUO Shiming, ZENG Rensen, WANG Jianwu, HUANG Jinghua, LI Mei
    2004, (6):  1079-1082. 
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    The research advance in cyclic hydroxamic acids was reviewed in this paper.Cyclic hydroxamic acids are the important natural products of cereal crops.They and their respective derivatives are the constitutive compounds of a wide variety of gramineous plants and few dicot plants.They have structural diversity and different natural occurrences.Because of their phytotoxic properties,cyclic hydroxamic acids show a great variety of biological activities.They are the defensive agents against plant diseases,pests,nematodes and other plants.The distribution of cyclic hydroxamic acids in Zea mays and their variation in relation to the age were focused on in the paper.In Zea mays,there are structural diversity of cyclic hydroxamic acids and related benzoxazolinones.DIMBOA (1,4-benzoxazin-3(4H)-ones) is the most abundant derivative in Zea mays.The content of cyclic hydroxamic acids is strongly cultivar-dependent in Zea mays.Hydroxamic acids are not present in seeds.After germination,the level of DIMBOA increases,and the maximum level occurs in young seedlings a few days after germination.DIMBOA exists in all parts of plants,and its concentration is generally higher in shoots than in roots.In all stages,the young leaves of Zea mays have relatively high content of DIMBOA.The concentrations of these hydroxamic acids are highly dependent on environmental growth conditions.Under UV-light and water deficiencies,the levels of hydroxamic acids in plant increase rapidly.Cyclic hydroxamic acids exuded by Zea mays root can be quantitatively analyzed by HPLC.Supplying iron can significantly increase the exudation of DIMBOA from Zea mays root.
    Soil dissolved organic matter and its effect on chemical and biological behaviors of soil heavy metals
    LI Tingqiang, YANG Xiao'e
    2004, (6):  1083-1087. 
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    Dissolved organic matter (DOM) is an important and active component in both terrestrial and aquatic ecosystems,while soil DOM plays an important role in the pedogenesis,mineral weathering,and translocation of pollutants in soils.It has become a hotspot in environment science,soil science and ecology.Soil DOM has important effects on the chemical and biological behaviors of heavy metals in soil-plant system,but its mechanism is not identified.The study on soil DOM in China was still in its initial stages,and most studies only reported that the activity of heavy metals in soils was affected by the DOM produced from organic fertilizer.This review is to summarize the recent literatures regarding the formation of soil DOM and its affecting factors,and the effect of soil DOM on the chemical and biological behaviors of heavy metals in soils.The main affecting mechanisms of soil DOM on behaviors of soil heavy metals were summarized as complexing with heavy metals,competing with metals for adsorption sites,and affecting soil pH value.
    Research advance in characteristics of molybdenum,boron and selenium in red soils of South China and effects of their reasonable application on forage grass growth
    WENG Boqi, HUANG Dongfeng
    2004, (6):  1088-1094. 
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    Reasonable fertilization and fertility improvement of red soils are the important measures to develop the forage industry in hilly regions of South China.This paper summarized the existing form,chemical feature,availability and content of molybdenum,boron and selenium in red soils of South China.The lack of these three microelements in red soils was in common,and their reasonable application could significantly improve the growth of forage grass and its yield.The authors discussed the effects of molybdenum,boron and selenium application on the uptake and accumulation of available nutrients by forage grass and relevant physiological functions,described the molybdenum,boron and selenium deficiency symptoms of forage grass,their diagnostic methods and correcting measures,and put forward some suggestions for deepening the study.
    Mechanism of stomatal regulation by root sourced signaling and its agricultural significance
    GUO Anhong, LI Zhaoxiang, LIU Gengshan, YANG Yuanyan, AN Shunqing
    2004, (6):  1095-1099. 
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    Under soil drought condition,root sourced signal abscisic acid (ABA) plays an important role in the long distance signaling process,and can be a measurement of soil water availability.ABA is also an effective stomatal closing agent,and acts to reduce transpiration and canopy water loss.This paper briefly introduced the physiological mechanism and theoretical model about the stomatal regulation by root sourced signaling,and indicated that the combination of this model with root water absorption model and stomatal conductance model could be more effective in depicting the response of plant to soil drying and atmospheric drought.In addition,some effective irrigation approaches,such as regulated deficit irrigation (RDI),partial root-zone drying (PRD) and controlled alternative irrigation (CAI) were profited from the mechanism of plant water use regulation by the root sourced signaling.These irrigation measures favored to reasonably distribute available soil water in root zone.Root signaling system also played important role in regulating root growth and its development,retarding shoot growth to adjusting root shoot ratio,and optimizing assimilation allocation to favor to improve reproductive development.These processes hold substantial promise for enhancing crop water use efficiency.
    Antibiotics production by bacterial agents and its role in biological control
    WANG Guanghua, Jos M. Raaijmakers
    2004, (6):  1100-1104. 
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    Using bacteria to control plant diseases is one of the main strategies in plant protection,and its mechanism is commonly thought to be the production of antibiotics by bacteria.The produced antibiotics not only have structural diversity,but also have broad-spectrum activity against many pathogens.Experimental results showed that one kind of antibiotics could be produced by several bacterial strains,and one bacterial strain could also produced more than one kind of antibiotics.Recent development in molecular and bio-analytical techniques greatly promoted the research of bacterial bio-control,and the colonization survey of introducing bacterial strain to the rhizosphere and spermosphere of host plants.Besides bacterial genotypes,several biotic and abiotic factors including whether the pathogens existing or not,temperature,pH,carbon and nitrogen sources are also identified to affect the antibiotics production by bacteria.The authors illustrated some of the impeding problems in bacterial bio-control agents' application,and suggested that in the future research,more attention should be paid on developing mixed bio-control agent to avoid the anti-antibiotic activity of pathogens.
    Community characteristics in Hongchiba area of Wuxi County during ecological restoration after controlled burning
    HE Binghui, HAO Yunqing, LI Xuguang, HAN Chenxia, CHEN Changpei, ZHENG Guoci
    2004, (6):  1105-1108. 
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    This paper studied the species composition and the structure and species diversity of communities in Hongchiba area of Wuxi County after controlled burning and aerial sowing afforestation.The results showed that after burning and afforestation,pure Pinus armandii forest was not developed,but various mixed needle board-leaved forests which comprised P.armandii and native board-leaved trees grew.Various native species contributed to the communities with great species diversity.Shannon-Wiener index was 2.305～3.145,ecological dominance was 0.063～0.151,and evenness was 0.600～0.749 The natural regeneration of P.armandii population was very poor,and there was a trend that P.armandii would be gradually replaced by other native board-leaved trees.It was demonstrated that P.armandii should not be taken as a unique afforest tree,and controlled burning was not a favorite ecological measure in subtropical area.Native trees should play more important roles in the process of ecological restoration.
    Life table and spectral analysis of endangered plant Taxus chinensis var.mairei population
    HONG Wei, WANG Xingong, WU Chengzhen, HE Dongjin, LIAO Chengzhang, CHENG Yu, FENG Lei
    2004, (6):  1109-1112. 
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    Based on the investigation in Longxi Mountain National Nature Reserve and the theory of survival analysis,a static life table of Taxus chinensis var. mairei population was worked out,the curves of its survival rate,mortality rate and killing power were drawn,and the population dynamics was analyzed by spectral analysis.The results showed that the survival curve of the population appeared to be a type of Deevey-Ⅲ,and the high mortality of seeding was one of the important reasons which caused Taxus chinensis var. mairei to be endangered.The spectral analysis of the population showed that there was a marked periodic regularity in the process of natural regeneration of Taxus chinensis var. mairei.