Loading...
Welcome to Chinese Journal of Applied Ecology! Today is Share:

Table of Content

    15 February 2004, Volume 15 Issue 2
    Previous Issue    Next Issue
    Structure and dynamics of Taxus chinensis var. mairei clonal population
    LI Xiankun, XIANG Wusheng, SU Zongming
    2004, (2):  177-180. 
    Asbtract ( 0 )  
    Structure and dynamics of Taxus chinensis var. mairei clonal population were studied. The results showed that according to the life history of Taxus chinensis var. mairei, the modular population could be divided into 6 classes. The development of Taxus chinensis var. mairei population was greatly depended on its ramets, which sprouted on its stem, and the population size structure was stable. The survival curve of Taxus chinensis var. mairei population showed a revered ‘J' type. To expanding and continuing the population, there were high ramet sprouting rate and the resource limit induced a higher seedling and sapling mortality rate. When sapling grew up as young tree, its adventitious root stretched into soil to assimilate the nutrient and water, and it became independence individual. Before germination, the seed of Taxus need to dormant for more than one year, and the bird and beast liked to eat the seed, so it was hard to find seedling and sapling from seed. Therefore Taxus chinesis var. mairei had been considered to be a decline or none descendant population. In this study, it was found that Taxus chinensis var. mairei had a powerful asexual multiplication in Yuanbaoshan, especially ramet sprouting on stem. It was depend on this way to develop and expand the population.
    Influence of shelterbelts structure on snow distribution pattern in shelternets in Northeast China
    FAN Zhiping, ZENG Dehui, CHEN Fusheng, ZHU Jiaojun, JIANG Fengqi, SHA Jianguo
    2004, (2):  181-185. 
    Asbtract ( 0 )  
    The amount of snow that falls in farmland during winter in Northeast China is the important source of soil water in farmland, so the influence of shelterbelt structure on snow distribution pattern is the key problem in order to adjust structure of shelterbelts according to porosity in management practice. Based on snow depths in shelternets composed of shelterbelts with three levels of porosity, which were shelternet No. 1, shelternet No. 2, and shelternet No. 3, the snow distribution patterns in farmland were studied. The results showed that the structure of shelternet had great influence on snow distribution in farmland. With different levels of porosities, spatial pattern of snow distribution were obviously different in three shelternets. The more variant in porosity, the more obvious difference in snow distribution pattern, and the best uniformity of snow distribution appeared in shelternet with porosity of φ2w=0.579,φ2s=0.268, in which snow depth in farmland was relative even and the variability of snow depth was the least. Consequently, the relationship of porosity of shelterbelt with snow distribution pattern could be used to guide structure adjustment and optimization management of shelterbelts.
    Diversity of Frankia in nodules of Alnus nepalensis at Gaoligong mountains revealed by IGS PCR-RFLP analysis
    DAI Yumei, CAO Jun, TANG Xiaomeng, ZHANG Chenggang
    2004, (2):  186-190. 
    Asbtract ( 0 )  
    nodule samples were used to assess the diversity of Frankia strains symbiotically associated with Alnus nepalensis naturally occurring at the Gaoligong Mountains in Yunnan Province, China. DNA was extracted directly from nodules, and its two target DNA regions that encode nifD-nifK intergenic spacer (IGS) and 16S-23S rDNA IGS was studied by PCR-RFLP. The PCR fragments yielded by the nifD-nifK IGS were noticeably different in size, and when they were digested by HaeⅢ and AfaⅠ, 15 nif-type Frankia strains could be detected, the PCR-RFLP result of this region also could show that more than one genotype Frankia strains could form symbiosis with individual plants at the same time.The 16S-23S rDNA IGS had similar PCR fragments, but still identified 15 rrn-type strains after digested by HaeⅢ and AfaⅠ. 20 genotype strains could be found only when combined the PCR-RFLPs of two target regions.
    Effects of gap in primitive subalpine fir forest on diversity of herb and shrub in Tibet
    BIANBA Duoji, GUO Quanshui, CI Bai, LUO Daqing
    2004, (2):  191-194. 
    Asbtract ( 0 )  
    Effects of gap in primitive fir forest in southeast Tibet on species diversity of herb and shrub were studied. The results showed that species composition, distribution and diversity in gap were different from those in non-gap. The improvement of illumination and other habitat conditions resulted in richer species of herb and shrub in gap. There were shade-tolerant and photophilic herb species and shrub species in gap, however, only shade-tolerant herb species and shrub species grew in non-gap. Species diversity and evenness in gap were higher than in non-gap. The diminutive similar coefficient between herb and shrub communities showed that certain difference existed between herb and shrub communities in stands of gap and non-gap. The similar coefficients were little correlative between gap area and communities. Gap was important to improve growth of herb and shrub and maintain species diversity of primitive subalpine fir forest in southwest Tibet.
    Relationships between water and productivity of seabuckthorn (Hippophae) in different habitats of the Loess Plateau, China
    WEI Yukun, LIANG Zongsuo, CUI Langjun, HAN Ruilian
    2004, (2):  195-200. 
    Asbtract ( 0 )  
    This paper deals with the relationships between water and productivity of seabuckthorn in different habitats of the Loess Plateau in north Shaanxi. The typical habitats were classified with hilltop, sunny, shady, semi-shady and semi-sunny hillside. The results showed that values of transpiration of five kinds of habitats were different, and transpiration of semi-shady was relatively stronger in the morning while others were weaker. With the variation of directions of sunshine, transpiration of shady and sunny was declining and meanwhile transpiration of hilltop was steady. transpiration of semi-shady reached the peak in 12:00. In the afternoon, these values of transpiration all reduced in different extents except seabuckthorn of shady, especially semi-shady. The mean transpiration of 5 habitats was ordered in semi-shade >shade >semi-sunny >hilltop >sunny. There were remarkable difference between diffuse resistance and transpiration, and same relationship was found between relative humidity and transpiration. But this relationship was not found between light intensity and transpiration. Different habitats had different productivities, and productivity of seabuckthorn in shade habitat was higher than those in other habitats.
    Response of stomatal characteristics and its plasticity to different light intensities in leaves of seven tropical woody seedlings
    CAI Zhiquan, QI Xin, CAO Kunfang
    2004, (2):  201-204. 
    Asbtract ( 0 )  
    Stomatal characteristics and its plasticity in leaves of four canopy species, Shorea chinensis, Pometia tomentosa, Anthocephalus chinensis, Calophyllun polyanthum and three middle-layer species, Barringtonia pendula, Garcinia hanburyi, Horsfieldia tetratepala acclimated to different light conditions (8%, 25%, 50% and 100% of full sunlight) for more than one year were surveyed. All plant's stomata were distributed on the abaxial of leaves. Pometia tomentosa and Barringtonia pendula had higher stomatal density, and the guard cell length of Anthocephalus chinensis and Calophyllun polyanthum were much greater than others'. Stomatal density and stomatal index (ratio of stomatal numbers to epidermal cell number) were increased with growth irradiance increased, while numbers of stomata per leaf were higher in the low than the high relative PFD, and stomatal conductance of leaves was the highest in the 50% of sunlight except for Anthocephalus chinensis. The relative PFD had little effects on the guard cell length of all seven plants. There was a significant negative correlation between stomatal density and leaf area, but the stomatal conductance was not significantly positive with the stomatal conductance in some degree. The analysis of phenotypic plasticity of stomatal characteristics showed that plasticity index for stomatal index and numbers of stomatal per leaf were similar for canopy and middle-layer species, while the plasticity index of stomatal density and stomatal conductance were significantly greater for canopy species than middle-layer species. The high plasticity of canopy species was consistent with the hypothesis that specialization in a more favorable environment increases plasticity.
    Comparative study on daily change of photosynthesis rate of the rhizomatous grasses in milky ripe stage
    HE Wenxing, YI Jin, LI Hongmei
    2004, (2):  205-209. 
    Asbtract ( 0 )  
    Comparative study on daily change of photosynthesis rate of the rhizomatous grasses in their milky ripe stage was carried out, and the results showed that photosynthetic rate of five grasses appeared to be two-apex curve, except Elytrigia intermedia appeared to be one-apex curve. The general trend was that the higher the root/shoot ratio was, the later the first apex of the photosynthetic rate reached, and the shorter the noon break period was. Moreover, low relative humidity and high leaf temperature were the important factors for noon break. Leymus chinense, Pascopyrum smithii Rydb. cn. Rosana, Leymus secalinus, Leymus racemosus, Agropyron mongolicum and Elytrigia intermedia reached the first apex at 10:12, 10:00, 9:51, 9:39, 9:06 and 8:13, the noon break period was 471, 474, 464, 467 and 551 min, and the average leaf temperature during noon break was 37.8, 37.5, 36.9, 37.0 and 36.3 ℃, respectively. Leymus chinense and Agropyron mongolicum, Leymus secalinus and Leymus racemosus had similar daily change in photosynthetic rate, respectively, and their r values were 0.88 and 0.96 respectively when R=0.01.
    Simplification of crop shortage water index and its application in drought remote sensing monitoring
    LIU Anlin, LI Xingmin, HE Yanbo, DENG Fengdong
    2004, (2):  210-214. 
    Asbtract ( 0 )  
    Based on the principle of energy balance, the method for calculating latent evaporation was simplified, and hence, the construction of the drought remote sensing monitoring model of crop water shortage index was also simplified. Since the modified model involved fewer parameters and reduced computing times, it was more suitable for the operation running in the routine services. After collecting the concerned meteorological elements and the NOAA/AVHRR image data, the new model was applied to monitor the spring drought in Guanzhong, Shanxi Province. The results showed that the monitoring results from the new model, which also took more considerations of the effects of the ground coverage conditions and meteorological elements such as wind speed and the water pressure, were much better than the results from the model of vegetation water supply index. From the view of the computing times, service effects and monitoring results, the simplified crop water shortage index model was more suitable for practical use. In addition, the reasons of the abnormal results of CWSI>1 in some regions in the case studies were also discussed in this paper.
    Phosphorus translocation and distribution in intercropping systems of soybean (Glycine max) and citrus (Citrus poonensis)
    ZHOU Weijun, WANG Kairong, LI Hesong
    2004, (2):  215-220. 
    Asbtract ( 0 )  
    A field mini-plot experiment was conducted on clay loamy oxisol using 32P trace technique when P fertilizer was applied in three depth soil (15, 35 and 55 cm soil layer) to compare P absorption, distribution and translocation in plant organ and soil profile under soybean and citrus monoculture and intercropping at Taoyuan Experimental Station of Agroecosystem Research of Chinese Academy of Science. Total P uptake (PT) and P accumulation in different parts (PA) of soybean were remarkably decreased under intercropping. When 32P was applied in topsoil (15 cm soil layer), 32P uptake ( 32PT) by soybean was significantly lower in intercropping than in monoculture. Whereas 32PT uptake by soybean was significantly greater in intercropping than in monoculture when 32P was applied in deep soil layer (35 cm or 55 cm soil layer). However, considerable difference was not observed for 32P translocation and distribution among soybean organs. 32PT uptake by citrus was much lower under intercropping than under monoculture. The P uptake by citrus newly could be transferred rapidly to aboveground and prior to active growing organ. Intercropping did not affect 32P distribution in citrus organ, but when P was applied in deep soil layer, the speed of 32P transferred to aboveground and active organ was slowed down. P mobility was strengthened in soil profile, and P of deep soil layer was promoted to move to topsoil in intercropping. The experimental results showed the optimal depth of applied P should be within 20 cm soil layer in soybean-citrus intercropping system.
    Effects of peanut mixed cropping with different gramineous plants on apoplast iron accumulation and reducing capacity of peanut.
    ZUO Yuanmei, ZHANG Fusuo
    2004, (2):  221-225. 
    Asbtract ( 0 )  
    The effects of peanut mixed cropping with five different gramineous plants on apoplast iron accumulation and reducing capacity of peanut were investigated by soil culture experiment. The results showed that mixed cropping of maize, barley, oats, wheat, and sorghum with peanut could improve iron nutrition of peanut respectively. The phytosiderophores excretion rate of barley, oats and wheat were much higher than that of maize, and the phytosiderophores excretion rate of sorghum was lower than that of maize. In comparison with peanut in monocropping, the iron content in different organs of peanut mixed with maize, barley, oats, wheat and sorghum were increased. The Fe content in root apoplast of peanut mixed with five different gramineous was gradually increased and higher than that of peanut in monocropping at different growth days. At the same time, the mixed cropping systems remarkably improved the soil Fe availability in the rhizosphere and root Fe reducing capacity of peanut. The higher root Fe (Ⅲ) reducing capacity and much more available Fe in the rhizospe (Ⅲ) of peanut in mixed cropping played an important role in improving iron nutrition of peanut.
    Accumulation pattern of dry matter, nitrogen, phosphorus, potassium and silicon in rice genotypes and their relationships
    JIANG Ligeng, GAN Xiuqin, WEI Shanqing, XU Jianyun, CAO Weixing
    2004, (2):  226-230. 
    Asbtract ( 0 )  
    The accumulation of dry matter, nitrogen, phosphorus, potassium and silicon in 30 rice genotypes and their relationships under field condition were studied. The results showed that dry matter accumulated at ripening stage linearly increased with increase of nitrogen, phosphorus, potassium and silicon accumulation with highly significant correlation coefficients at both early and late season. At the same time, balance of nitrogen, phosphorus, potassium and silicon accumulation was beneficial for dry matter accumulation, which linearly increased with increase of nutrient balance index and decreased with increase of nutrient deviation index. The nitrogen, phosphorus, potassium and silicon were accumulated at the rate of 3.76:1:4.55:7.10 at early season and 2.88:1:4.54:8.09 at late season. During growth period, dry matter accumulation was the highest at middle stage, then late stage and early stage. But nitrogen accumulation was the highest at early stage, then middle stage and late stage. The dry matter accumulated before heading was mainly distributed in stem and leaf sheath, with the highest ratio of stem and leaf sheath to total dry matter at heading stage. In contrast, nitrogen accumulated before heading was mainly distributed in leaf blade, and the ratio of nitrogen in leaf blade to total nitrogen was higher than that of dry matter at either growth stages. Dry matter, nitrogen, phosphorus accumulated at ripening stage were mainly distributed in panicle with rates of 58.01%,66.42% and 70.06%, respectively. But potassium accumulated at ripening stage was mainly distributed in stem and leaf sheath with the rate of 62 08%. Silicon was largely distributed in stem and leaf sheath at early season with the rate of 43.11%, but distributed largely in panicle at late season with the rate of 46.99%.
    A dynamic knowledge model for wheat target yield design and variety selection
    ZHU Yan, CAO Weixing, DAI Tingbo, JIANG Dong
    2004, (2):  231-236. 
    Asbtract ( 0 )  
    Based on integrating the effects of yield potential of photosynthesis and temperature, average yield level of last three years, soil fertility, fertilization and water management level and production technology level on yield increment, the dynamic yield increment index was quantified and a wheat knowledge model for design of target yield under different temporal and spatial environments was developed through knowledge engineering and system analysis method. By quantitatively calculating suitability of variety characteristics to environmental conditions and production requirements, a knowledge model for variety selection was established. Case studies on the target yield design with the data sets of five different eco-sites, three climatic years and average yield levels of last three years, two soil fertility levels and three fertilization and water management levels, and on suitable variety selection models with the data sets of five different eco-sites, normal climatic year and fifteen typical varieties indicated a good performance of the model system in decision-making and wide applicability.
    Microbial eco-characterization and its restoration in copper reclaimed wasteland in red soil area of China Ⅱ. Effects on soil microbial characteristics and community structure
    LONG Jian, HUANG Changyong, TENG Ying, YAO Huaiying
    2004, (2):  237-240. 
    Asbtract ( 0 )  
    Soil microbial features in Lipu copper mining and non-mine soil were studied comparatively. The results indicated that mine soil possessed obviously different microbial features such as lower microbial biomass carbon and soil basal respiration strength, Cmic/Corg decreasing, and higher microbial ecophysiological parameters qCO2, indicating that heavy metal had a depressive impact on soil microbial eco-characteristics. Biolog data showed that mine soil microbial community structure was changed obviously, the speed and quantity of carbon consuming were increased significantly, and the kinds of carbon sources which soil microorganism used were changed, led to consume much more energies for maintaining the normal needs of its life. But the utilization efficiency was lower compared with the control. All the results showed that soil microbial eco-characteristics could be used as a sensitive, effective and liable index of mine soil environment qualities.
    Modification and its application of generalized Schumacher model
    HONG Wei, WU Chengzhen, YAN Shujun
    2004, (2):  241-244. 
    Asbtract ( 0 )  
    Based on the concrete analysis on growth equations presented by others, a modified Schumacher growth equation was proposed as, which included Gompertz function, Schumacher equation and generalized Schumacher equation, and had stronger self-adaptability and practicality. The analytic character and adaptability of the modified Schumacher equation were analyzed. According to the genetic algorithms method, this model was used to fit the growth data of endangered plant of Tsuga longibracteata and Platycladus orientalis. The results showed that the modified Schumacher equation was not only better than Schumacher equation and generalized Schumacher equation significantly, but also better than classical Logistic model and Li's self-adaptive model. So it could be used to study the dynamics simulation for tree growth and dynamics law for population growth.
    Problems in development of agriculture-animal husbandry ecotone and its countermeasures
    BAOYIN Taogetao, BAI Yongfei
    2004, (2):  245-248. 
    Asbtract ( 0 )  
    Problems in development of Duolun, a typical agriculture-animal husbandry ecotone, and its countermeasures were discussed in this paper. Economic structure was not rational in Duolun, and it should develop industry and commerce, limit the scope of agriculture and animal husbandry, and actively increase efficiency of agriculture and animal husbandry. The structure of land use was not rational, and the main countermeasures were to increase area of forestland and grassland, and decrease cultivated area. On resources use, the main countermeasures were to exploit water resource rationally and bring into play resource superiority of mutually benefits on agriculture and animal husbandry. The ecological environment construction was the foundation of the national economy for sustainable development in agriculture-animal husbandry ecotone.
    Analysis on the dynamics of desert-oasis vegetation in the Sangong River Basin
    ZHAO Chengyi, SONG Yudong, WANG Yuchao, JIANG Pingan
    2004, (2):  249-254. 
    Asbtract ( 0 )  
    Taking the Sangong River Basin as a typical research area, the relationships between the change of landscape pattern of desert-oasis and the dynamics of vegetation were studied in this paper, and the evolution of the landscape pattern of desert-oasis was also discussed. The results showed that the main characteristics of landscape pattern were the dynamics of vegetation. It had the impact on the vegetation by the changes of topography, water resources using, corridor of river and drainage channel. It was shown the great variability for the height, cover and biomass of vegetation with the change of landscape pattern. Taking the corridor of river as the center, it usually showed a zone distribution from inside to outside for the desert-oasis landscape pattern. The vegetation types evolved from the tree-shrub mixed forest, thicket meadow, salinized meadow to desert with the change of the condition of water and heat in the basin. The stability of natural patch was higher than that disturbed by mankind or manmade patch. Usually, the stability of each patch was in order of desert>sandy land>urban>pond>paddy field>grass land>vegetable plot>woodland>residential area>saline-alkali land>wasteland>farming land>orchard. The landscape pattern of desert-oasis in the research area was developed by human activities based on natural oasis.
    Establishment and growth of Lolium multiflorum for phyto-remediation of Pb/Zn tailings
    JIAN Shuguang, YANG Zhongyi, JIAN Weijun
    2004, (2):  255-260. 
    Asbtract ( 0 )  
    Following the cropping of Sesbania rostrata, Lolium multiflorum was cropped as the subsequent species on an acidified Pb/Zn tailings site. As the experimental treatments, S.rostrata issues harvested on the site were removed from the site or buried into the tailings as the green manure. Changes of tailings chemical and physical properties, germination, growth and heavy metal accumulation of Lolium multiflorum were investigated. The results showed that cropping of S.rostrata improved the chemical and physical properties of the tailings, especially for the contents of organic matter, total nitrogen, available phosphorus and available potassium. The strong acidity (pH<3) in the Pb/Zn tailings was the main factor that limited the establishment of L.multiflorum.The tailings acidity was decreased temporarily by lime application and it seemed to be helpful only for the germination because the strong acidity was restituted in the end of the experiment. In the most cases,L.multiflorum succeeded to germinate, grow and establish on the Pb/Zn tailings, and yielded relatively great biomass (DM 1.4～3.2 t·km-2). Compared to CK (without S.rostrata cropping), cropping S.rostrata increased the biomass of subsequent L.multiflorum by 4.8%～39.5% in case without S.rostrata green manure using and by 7.7%～139.5% in case with the green manure using, and the green manure application resulted in 2.7%～75.8% increment of L.multiflorum biomass. The results proved that the artificial vegetation process using S.rostrata and subsequent L.multiflorum would be a successful pioneer stage for restoration of the Pb/Zn tailings.
    Effects of different light transmission rate on American ginseng's photosynthesis
    LI Wanlian, WAN Zhihu, YANG Shuyun
    2004, (2):  261-264. 
    Asbtract ( 0 )  
    From 1997 to 1998, series of experiments were carried out to study American ginseng's photosynthesis related to light transmission rate of plastic cover. The results showed that American ginseng's light saturation point for photosynthesis was different under the different light transmission rate (LTR) because of shading. At about 29 0℃ and under 12%, 30%, 42% LTR, 4-year-old American ginseng's light saturation point were 171 0, 323 0, and 429 0 μmol·m-2·s-1, respectively. The maximum net photosynthesis rate (Pn) was 6.54 mg CO2·dm-2·h-1, which appeared under the shading of 30% LTR. The daily course of 3-year-old American ginseng's Pn changed with LTR. When LTR was less than 25.8%, the daily curves of Pn had a single peak, and when LTR was higher than 25.8%, it had two peaks and the leaf's photosynthesis noon break phenomenon was remarkable. The results of single correlative analysis showed that the dominant factor that influenced Pn was photon flux density (PFD), and the results of plural regression analysis showed that the synthetic effect of all the influencing factors together on Pn was significant.
    Vertical distribution character of nutrient elements in peat of Sanjiang Plain
    YU Junbao, WANG Jinda, LIU Jingshuang
    2004, (2):  265-268. 
    Asbtract ( 0 )  
    Based on the methods of sampling in winter and dividing soil layer on the site, the vertical distribution character of normal amount nutrient elements N, P, Mg, Ca, Fe and nutrient trace elements Cu, Zn, Mn, B in peat of river bed-flood land and valley depression land in the Sanjiang Plain was studied systematically. The results showed that TN was accumulated in surface layer of peat, and TP was accumulated in root layer. The contents of TN and TP were decreased with the section depth increasing. Zn, Mn, B, Mg and Fe were gathered in root layer and accumulated sharply in gley horizon of silt sub-clay, and the content of Ca was regular relatively in each layer of section. There were close correlations among some nutrient elements in peat section.
    Spatial pattern analysis of forest landscape in low coteau of Middle Qilian Mountains
    YANG Guojing, XIAO Duning
    2004, (2):  269-272. 
    Asbtract ( 0 )  
    Based on the vegetation map and the relief map, using GIS and Fragstats, the spatial pattern of forest landscape of Xishui reserve in Qilian Mountains were analyzed. The results showed that the distribution of the vegetation was impacted mostly by altitude and aspect, grassland was mostly distributed on the land of altitude 2 500～2 900 m and aspect of south and southwest,Picea crassifolia forest was always in the land of altitude 2 900～3 300 m and aspect of north, northeast, east and northwest, and shrubbery was in the land of altitude 3 300～3 700 m. The grassland had the biggest area and its connectivity and integrality were the best. The biggest MPFD of Picea crassifolia forest meant that its shape was the most complicated, its mean patch area was small, and the distance between the patches was short. So Picea crassifolia forest was easy to be impacted by some disturbance. The forest suitable land and Sabina przewalskii forest showed more outstretched characteristics than farmland and land with few trees. The mean nearest-neighbor distance of the poplar forest was the biggest in all the landscape elements, so the poplar forest's fragmentized degree was the highest in all the landscape elements.
    Analysis of the landscape diversity dynamics of small watershed in the Loess Plateau
    WANG Xiaoyan, XU Zhigao, YANG Mingyi, TIAN Junliang
    2004, (2):  273-277. 
    Asbtract ( 0 )  
    Taking Zhifanggou Gully as the study area, some landscape diversity indexes were attained under the support of GIS technology. Utilizing the indexes such as patch size, average fractal dimension, diversity index, dominance, evenness, fragmentation and conglomeration, the changes of landscape diversity in the small watershed in Loess Plateau during the past 40 years were studied. The landscape diversities had been increasing for the recent 40 years due to the effect of both human activity and plants' endogenesis succession. The patches number increased, and the dryland matrix was substituted gradually by other matrixes such as meadow and woodland. The landscape pattern trended to be fragmentized and the indexes of landscape type diversity and evenness increased, while landscape diversities changed greater during 1978～1998 than during 1958～1978. Homogeneous dryland matrix landscape ecosystem in 1958 had already changed into heterogeneous meadow and woodland matrix landscape ecosystem, which had greater structure stability and stronger function than before.
    Distributed modeling of nutrient transport in basin with support of remote sensing and geography information system
    LI Shuo, SUN Bo, ZENG Zhiyuan, ZHAO Qiguo
    2004, (2):  278-282. 
    Asbtract ( 0 )  
    Agricultural non-point source pollution has become serious in our country. Modeling the processes of nutrient(especially nitrogen and phosphorus) transport in basin and evaluating the adopted management practices are important for controlling the impact of non-point pollution on environment. A research scheme for distributed simulation of nutrient transport processes in Lianshui Basin, Xingguo County, Jiangxi Province was designed, with the support of remote sensing (RS) and geography information system (GIS). The research procedure included model selection, discretization and spatial parameterization of the basin, prediction, and validation. SWAT model was selected, and basin-subbasin-hydrological response unit discretization scheme was designed. Supported by RS and GIS and based on the topographic features of the watershed, the subwatershed discretization divided the watershed into subbasins, and each subbasin could be further partitioned into multiple hydrologic response units (HRUs), which were unique soil/land use combinations within the subbasin and modeled through statistical spatial overlay analysis. The parameters of land use were obtained from the supervised classification of TM imagery based on field training samples, and those of soil were obtained from field sampling and further interpolated through geostatistical method. The simulation was carried out by using the data from 1991 to 2000. The results showed that the simulation accuracy of annual runoff water yield and sediment yield was 89.9% and 70.2%, respectively.
    Spatial distribution and landscape ecological impact degree assessment of quarry in Zhuhai City
    WU Zhifeng, WANG Jizeng, ZHUO Muning, WAN Hongfu
    2004, (2):  283-286. 
    Asbtract ( 0 )  
    Artificial erosion is one of the typical artificial landscape degradation. Based on the support of GIS and RS and combined with field investigation data, the spatial distribution characteristics and landscape ecological impact degree of quarry were analyzed. There were 235 quarries in Zhuhai city, which concentrated on Sanzao town and Jingan town. According to buffer analysis, the quarries distribution had a obviously logarithm relationship with its distances from roads. 152 quarries with the area of more than 5000 m2 were assessed by landscape ecological impact degree (LEI) index. The results indicated that 9 quarries belonged to great influence level and 19 quarries belonged to strong influence on ecological environment.
    Distribution and stock of mercury in typical wetland plant in the Sanjiang Plain
    LIU Ruhai, WANG Qichao, LU Xianguo, LI Zhibo, WANG Yan
    2004, (2):  287-290. 
    Asbtract ( 0 )  
    Total mercury concentration of typical wetland plant was analyzed. There were great difference in mercury content among different plants, and the order was moss > alga > carex > herb > shrub. There was a trend of increasing total Hg concentrations from vascular plants to bryophytes, and from dry to wet site. The wetland soil was the source of mercury in the air close to the ground, so it influenced the content of mercury in the plant. In different components of plants, mercury contents were in the order of dead stand > root > leaf > stem. Mercury concentration increased in initial stage and decreased in the end of the growing season. According to the mercury content and biomass, the mercury stock of plant were calculated, and it was 24 9 μg·m-2 in the above ground of plant in Calamagrostis angustifolia wetland and 35 8 μg·m-2 in Carex lasiocarpa wetland.
    Difference of lead uptake and distribution in rice cultivars and its mechanism
    LIU Jianguo, LI Kunquan, ZHANG Zujian, LU Xiaolong, YU Biyu, CAI Yixia, YANG Jianchang, ZHU Qingsen
    2004, (2):  291-294. 
    Asbtract ( 0 )  
    In order to investigate the uptake of lead by rice plant and the distribution of lead in different parts of rice, pot experiment was conducted with 20 rice cultivars of different genotypes by adding lead to soil. The results showed that there existed significant differences among the cultivars in the lead uptake and distribution by rice plants, but the differences had no obvious relationship with rice genotypes. The lead concentrations decreased rapidly from roots to grains along rice plants, so the concentrations of lead were very low in grains compared with other parts of rice plants. The regression analysis showed that there were significant negative correlations between adjacent organs of rice plant, but positive correlations, mostly significant, between disconnected organs, for the lead concentrations in them. Lead concentration in the leaf of heading stage showed a significant positive correlation with that in the grain of ripening stage. Lead was not distributed uniformly in different parts of grain structure, and the lead accumulation in polished rice was only 32.88% of the total lead accumulation in grain.
    Degradation of methyl parathion in soil and Chinese chive by strain DLL-1
    ZHANG Ruifu, JIANG Jiandong, CUI Zhongli, LI Shunpeng
    2004, (2):  295-298. 
    Asbtract ( 0 )  
    Degradation of methyl parathion in soil and Chinese chive by strain DLL-1 was studied. Usage of methyl parathion at 7.5, 15, and 22.5 kg(a.i.)穐m-2 resulted in the average amount of residue of 0.663, 1.270, and 1.901 mg穔g-1 in Chinese chive respectively. The natural degradation rate was 98.94%, 96 44%, and 96.04% corresponding to the 3 levels of usage. The amount of pesticide residue could be significantly decreased through the application of high effective degrading microbial agents. The amount of pesticide residue in Chinese chive and soil was 0.269 and 0.099 mg穔g-1 with the usage of 75 kg穐m-2 of degradation bacterium, which was decreased by 78.82% and 98.68% compared with the control. Increasing the bacterium usage led to the increase of degradation rate. Usage of degradation bacterium more than 75 kg穐m-2 did not increase the degradation rate further. The best time of the application of the degrading microbe was 3 days after the application of the pesticide.
    Host plant suitability and reproductive isolation of two Schizotetranychus bambusae populations from the bamboo species Phyllostachys pubescens and Neosinocalamus affini
    LIU Huai, ZHAO Zhimo, DENG Yongxue, DENG Xinping, HE Lin, WU Shiyuan, SHUAI Xia
    2004, (2):  299-302. 
    Asbtract ( 0 )  
    Development, survivorship, reproduction and procreation isolation of Schizotetranychus bambusae from the bamboo species Phyllostachys pubescens and Neosinocalamus affinis reared on different host plants were evaluated in laboratory. The results showed that the population of S.bambusae from Phyllostachys pubescens (PhS) failed to complete its life cycle when reared on the leaf of N.affinis. When the population of S.bambusae from N.affinis (NeS) was reared on the leaf of P.pubescens, the survivorship and fecundity decreased. The rm, λ and Ro were 0.0391, 1.0399 and 2.5542, respectively. At 27℃, when the PhS was reared on P.pubescens, rm, λ and Ro were 0.1415, 1.1520, and 15.6298, respectively, whereas NeS was reared on N.affinis,rm,λ, and Ro were 0.0993, 1.1044, and 10.0622, respectively. Reciprocal cross test between PhS and NeS showed that the two populations could mate, but laid unfertilized eggs that produced male only, indicating the existence of reproductive isolation.
    Cooperative effect of Spodoptera litura nuclear polyhedrosis virus with parasite wasp, Microplitis sp. on the S.litura larvae
    JIANG Jiexian, JIANG Zhurui, LEI Runhua
    2004, (2):  303-307. 
    Asbtract ( 0 )  
    The relationship between the survival rate, developmental duration of Microplitis sp. in Spodoptera litura larvae and time of exposure of the host larvae to virus, the inoculation virus concentration were investigated to determined if parasites which emerged from virus-infected S.litura larvae had normal survive, and if the parasites could sever as the vector for S.litura nuclear polyhedrosis virus (SlNPV). There was no significant difference in time that parasites spent in virus-infected larvae and healthy one, indicating the SlNPV did not affect the developmental period of Microplitis sp. Parasite larvae in hosts exposed to virus after parasitization compmeted their development before their hosts died of virus infection. The proportion of parasites survived varied with the inoculation virus concentration and the time of exposure of the host larvae to virus, the percent of parasites survived increased as the time between host parasitization and host virus exposure increased, and decreased as the inoculation virus concentrations increased. The female parasites which developed or oviposited in virus-infected hosts, and manually contaminated the ovipositor of the females with virus suspension could all carry infective doses of the virus, and transmit virus from infected larvae to healthy one through ovipositor. A female parasite which developed or oviposited in virus-infected hosts transmitted infective doses of the virus to an average of 2.14, 2.45 healthy host larvae exposed to it respectively. A female parasite from the cocoon contaminated with SlNPV of different virus concentration could transfer infective doses of the virus to an average of 1.45 healthy host larvae.A female parasite exposed to the mixture of different virus concentration and 10% honey-water solution could also transmit virus to an average of 0.94 larva.
    Population dynamics of Microtus fortis in Dongting Lake region and its forecasting
    WANG Yong, GUO Cong, ZHANG Meiwen, LI Bo, CHEN Anguo
    2004, (2):  308-312. 
    Asbtract ( 0 )  
    The population dynamics of Microtus fortis in Yueyang, Hunan Province was studied from 1991 to 1996. M. fortis lived on the beach of the lake from early autumn to next spring, but moved to the farmland in summer when the beach was flooded. When lived on the beach, its population increased gradually. Usually, M. fortis made great damage on the crops when moved to the farmland. The population dynamics of M. fortis was different on the beach and on the farmland, and the key affecting factors were also different. Lake beach was the most suitable habitat for M. fortis. When it emerged in autumn, M. fortis moved back on it. The main breeding season of M. fortis inhabited on the beach was from October to May, and its population density increased gradually. The period between the beach emerged and been flooded determined the population size of the animal moved to farmland. Another factor was the rainfall in March. Farmland was not the suitable habitat for M. fortis. Because of the low breeding potential, high mortality and dispersal on farmland, its population density kept decreasing, and was very low in winter. The population density on farmland dropped dramatically when the lake beach emerged. The animal population was forecasted by means of regression analysis, and a linear regression equation was obtained. The predicted values matched with the real population densities of the animal in the field.
    Suspending particulates in rotifer-culturing pond ecosystem
    ZHAO Wen, LI Xiaodong, ZHAO Zhenxing, LIU Qing
    2004, (2):  313-315. 
    Asbtract ( 0 )  
    A comparative study on the structure and dynamics of suspending particulates in static and current water rotifer-culturing ponds showed that the total content of suspending pariculates varied from 6.76 to 65.39 mg稬-1, with an average of 11.50 mg稬-1 in static water ponds, among which, organic pariculates accounted for 66.8%, while inorganic particulartes occupied 33.2%. In the organic pariculates, both particulate detritus and bacteria accounted for 31%, while phytoplankton and zooplankton occupied 30.5% and 5.3%, respectively. The amount of suspending pariculates in current water ponds was 41.83 mg稬-1 in average, among which, organic pariculates accounted for 70.4%, while inorganic pariculates occupied 29.6%. In the organic pariculates, both particulate detritus and bacteria accounted for 39.2%, while phytoplankton and zooplankton occupied 30% and 1.2%, respectively. The content of suspending pariculates in static water ponds was less than those in current water ponds. Rotifer-culturing pond was a special type of ecosystem, where Brachionus plicatilis was the major consumer, its community structure was sample, and the abiotic factors were easy to be changed, which resulted in the dynamics of suspending pariculates content in ponds. The ratio of organic to total pariculates in rotifer-culturing ponds was higher, and the contents of both particulate detritus and bacteria were corresponding to that of plankton.
    Methodology of enacting standards for remediation of contaminated soils
    ZHOU Qixing
    2004, (2):  316-320. 
    Asbtract ( 0 )  
    Remediation technology for contaminated soils is being developed rapidly in recent years. However, there is a hysteresis in enacting remediation standards for contaminated soils. In particular, no corresponding research has been done in China. Methodology of enacting standards for the remediation of contaminated soils is discussed in order to promote the work in this field. It is emphasized that technological cleanup levels including limits of detection, environmental background levels and regulatory cleanup levels should be fully considered in the enactment of remediation standards.
    Research advance in ecotoxicology and environmental impact of veterinary medicines
    DIAO Xiaoping, SUN Zhenjun, SHEN Jianzhong
    2004, (2):  321-325. 
    Asbtract ( 0 )  
    Veterinary medicines or their metabolites could be discharged to the environment through different exposure routes, and had potential impacts to ecosystem in different levels, including individual, population, community and ecosystem. Their fate and potential impact have been widely researched in the world. This paper reviewed their exposure routes, fate in the environment, and impact on organisms in soils and waters and on soil processes. The significance of their environmental risk assessment was also analyzed.
    Influence of dissolved organic matter (DOM) on environmental behaviors of organic pollutants in soils
    LING Wanting, XU Jianmin, GAO Yanzheng, WANG Haizhen
    2004, (2):  326-330. 
    Asbtract ( 0 )  
    Dissolved organic matter (DOM) is an important component of solutions in terrestrial and aquatic ecosystems through its influence on acidity, nutrient availability, and toxicity. DOM could enhance the apparent solubility of organic pollutants and alter adsorption-desorption equilibrium of organic pollutants on soil. The enhancement of organic pollutants desorption in the presence of DOM could facilitate the mobility of organic pollutants in soil. On the other hand, the sorption of DOM by solid sorbents in soil could also enhance the retention of DOM-associated organic pollutants in soil. Furthermore, as a photosensitizer, DOM could promote the photogradation of organic pollutants in soil. And under certain condition, DOM also affected the hydrolysis of organic pollutants in soil solution. The effects of DOM on environmental behaviors of organic pollutants in soils were related to the physico-chemical characteristics of organic pollutants, DOM, and soil.
    Physiological adaptations of Sichuan golden monkeys (Rhinopithecus roxellana)to high altitude habitat in the Qinling Mountains
    GAO Yunfang
    2004, (2):  331-334. 
    Asbtract ( 0 )  
    The golden monkey (Rhinopithecus roxellana) is a special species in China, and possesses the highest altitude habitat (4 167 m) in all kinds of primates. So it is very important to study this monkey how to adapt to such a high and severe habitat. According to our research results in recent years and relative publications, this paper, from digestive, respiratory, blood, circulative and reproductive systems, inquired into the Sichuan golden monkey (Rhinopithecus roxellana), a named species for golden monkey, how to adapt to the high altitude habitat in the Qinling Mountains and what was the mechanism of these adaptations.
    Conservation tillage systems in North America and their significance for China
    YANG Xueming, ZHANG Xiaoping, FANG Huajun, LIANG Aizhen, QI Xiaoning, WANG Yang
    2004, (2):  335-340. 
    Asbtract ( 0 )  
    Soil degradation through erosion and desertification reduces soil productivity, and is a serious problem in agricultural production of China. To avert our arable land from further degradation, soil management must be shifted from degrading tillage to conservation practices. Over viewing the technology used in the 20th century for controlling soil degradation from erosion, conservation tillage developed in the United States and adopted in South America and Africa is one of the most successful measures to overcome soil degradation problems. This paper reviewed the historical development and the current situation of conservation tillage systems used in North and South America, with special reference to their effects on soil erosion control and soil quality. The increasing adoption of conservation tillage systems in North and South America and Africa followed an enhanced awareness of the increasing risk of soil erosion and the high cost of fuel associated with conventional tillage. Many crucial points for successfully adopting conservation tillage systems were emphasized, such as equipment/tool development and chemical weed control. Adopting conservation tillage could provide China with low-priced means of reducing soil degradation and improving soil and water quality.
    Impact of pesticides on biodiversity in agricultural areas
    WU Chunhua, CHEN Xin
    2004, (2):  341-344. 
    Asbtract ( 0 )  
    Large amount application of pesticides caused a lot of ecological and environmental problems, among which, the impact of pesticides on biodiversity was most important. In this paper, an overview of the impacts of pesticides on biodiversity in agricultural areas, including the community structure of insects, populations of soil invertebrates and microorganisms, and plant communities was provided, and the reasonable use of pesticides and the measures of protecting biodiversity in agricultural areas were also put forward.
    Effects of rice volatile infochemicals on insects
    ZHOU Qiang, XU Tao, LUO Shiming
    2004, (2):  345-348. 
    Asbtract ( 0 )  
    Plant volatile is not only the key of the relationship among plant, herbivore and its natural enemy, but also the foundation for the theory and practice of pest manage. In this paper, the chemical characteristic of rice volatile and its function among herbivore and its natural enemy were reviewed. The application and development direction of rice volatile infochemicals were proposed. Two directions to study the rice volatile infochemicals, which could be used in pest control, were also discussed. One was the physiology and biochemistry of little molecule signals, which was the key of rice second metabolize, and the other was the base of sense, identify and learn of pest insect to rice volatile infochemicals.
    Forest health ecological risk assessment in China
    XIAO Fengjin, OUYANG Hua, CHENG Shulan, ZHANG Qiang
    2004, (2):  349-353. 
    Asbtract ( 0 )  
    Forest health ecological risk assessment is an important factor in forest resources management. In this paper, we selected forest fire, forest disease-pest disasters and acid rain as main risk sources, described the risk resources by probability, intensity and distributing, and mapped each risk source. The endpoints were the damages that the risk acceptor might and these damages might cause ecosystems' organization and function changing under the uncertainty risk sources. Endpoints of forest might compose of productivity descent, reducing biodiversity, forest degrading, forest ecological function declining, furthermore, forest disappearing. We described exposure in terms of intensity, space, and time. In the exposure and hazard analysis, we used fragile index to show frangibility or resistibility (resistibility is reverse to frangibility), and analyzed the damages by different risk sources. Risk assessment and management was the integrated phase of the research. Because of the spatial heterogeneity of risk sources, all risk index were overlaid in the China map by GIS, which divided the region into 30 ecological risk sub-zones (provinces), according to risk index of each risk sub-zone, and the forest in China was divided into six levels of risk zones. In every level of risk zones, we also put forward the countermeasures for forest health ecological risk management. The result of assessment could provide scientific basis for forest management.
    Application of artificial neural network based on the genetic algorithm in predicting the root distribution of winter wheat
    LUO Changshou, ZUO Qiang, LI Baoguo
    2004, (2):  354-356. 
    Asbtract ( 0 )  
    In this study, a controlled experiment of winter wheat under water stress at the seedling stage was conducted in soil columns in greenhouse. Based on the data gotten from the experiment, a model to estimate root length density distribution was developed through optimizing the weights of neural network by genetic algorithm. The neural network model was constructed by using forward neural network framework, by applying the strategy of the roulette wheel selection and reserving the most optimizing series of weights, which were composed by real codes. This model was applied to predict the root length density distribution of winter wheat, and the predicted root length density had good agreement with experiment data. The way could save a lot of manpower and material resources for determining the root length density distribution of winter wheat.
    Structure and dynamics of Taxus chinensis var. mairei clonal population
    LI Xiankun, XIANG Wusheng, SU Zongming
    2004, (2):  177-180. 
    Asbtract ( 1033 )   PDF (1192KB) ( 345 )  
    Structure and dynamics of Taxus chinensis var. mairei clonal population were studied. The results showed that according to the life history of Taxus chinensis var. mairei, the modular population could be divided into 6 classes. The development of Taxus chinensis var. mairei population was greatly depended on its ramets, which sprouted on its stem, and the population size structure was stable. The survival curve of Taxus chinensis var. mairei population showed a revered ‘J' type. To expanding and continuing the population, there were high ramet sprouting rate and the resource limit induced a higher seedling and sapling mortality rate. When sapling grew up as young tree, its adventitious root stretched into soil to assimilate the nutrient and water, and it became independence individual. Before germination, the seed of Taxus need to dormant for more than one year, and the bird and beast liked to eat the seed, so it was hard to find seedling and sapling from seed. Therefore Taxus chinesis var. mairei had been considered to be a decline or none descendant population. In this study, it was found that Taxus chinensis var. mairei had a powerful asexual multiplication in Yuanbaoshan, especially ramet sprouting on stem. It was depend on this way to develop and expand the population.
    Influence of shelterbelts structure on snow distribution pattern in shelternets in Northeast China
    FAN Zhiping, ZENG Dehui, CHEN Fusheng, ZHU Jiaojun, JIANG Fengqi, SHA Jianguo
    2004, (2):  181-185. 
    Asbtract ( 1186 )   PDF (1365KB) ( 300 )  
    The amount of snow that falls in farmland during winter in Northeast China is the important source of soil water in farmland, so the influence of shelterbelt structure on snow distribution pattern is the key problem in order to adjust structure of shelterbelts according to porosity in management practice. Based on snow depths in shelternets composed of shelterbelts with three levels of porosity, which were shelternet No. 1, shelternet No. 2, and shelternet No. 3, the snow distribution patterns in farmland were studied. The results showed that the structure of shelternet had great influence on snow distribution in farmland. With different levels of porosities, spatial pattern of snow distribution were obviously different in three shelternets. The more variant in porosity, the more obvious difference in snow distribution pattern, and the best uniformity of snow distribution appeared in shelternet with porosity of φ2w=0.579,φ2s=0.268, in which snow depth in farmland was relative even and the variability of snow depth was the least. Consequently, the relationship of porosity of shelterbelt with snow distribution pattern could be used to guide structure adjustment and optimization management of shelterbelts.
    Diversity of Frankia in nodules of Alnus nepalensis at Gaoligong mountains revealed by IGS PCR-RFLP analysis
    DAI Yumei, CAO Jun, TANG Xiaomeng, ZHANG Chenggang
    2004, (2):  186-190. 
    Asbtract ( 974 )   PDF (793KB) ( 291 )  
    nodule samples were used to assess the diversity of Frankia strains symbiotically associated with Alnus nepalensis naturally occurring at the Gaoligong Mountains in Yunnan Province, China. DNA was extracted directly from nodules, and its two target DNA regions that encode nifD-nifK intergenic spacer (IGS) and 16S-23S rDNA IGS was studied by PCR-RFLP. The PCR fragments yielded by the nifD-nifK IGS were noticeably different in size, and when they were digested by HaeⅢ and AfaⅠ, 15 nif-type Frankia strains could be detected, the PCR-RFLP result of this region also could show that more than one genotype Frankia strains could form symbiosis with individual plants at the same time.The 16S-23S rDNA IGS had similar PCR fragments, but still identified 15 rrn-type strains after digested by HaeⅢ and AfaⅠ. 20 genotype strains could be found only when combined the PCR-RFLPs of two target regions.
    Effects of gap in primitive subalpine fir forest on diversity of herb and shrub in Tibet
    BIANBA Duoji, GUO Quanshui, CI Bai, LUO Daqing
    2004, (2):  191-194. 
    Asbtract ( 1083 )   PDF (1575KB) ( 271 )  
    Effects of gap in primitive fir forest in southeast Tibet on species diversity of herb and shrub were studied. The results showed that species composition, distribution and diversity in gap were different from those in non-gap. The improvement of illumination and other habitat conditions resulted in richer species of herb and shrub in gap. There were shade-tolerant and photophilic herb species and shrub species in gap, however, only shade-tolerant herb species and shrub species grew in non-gap. Species diversity and evenness in gap were higher than in non-gap. The diminutive similar coefficient between herb and shrub communities showed that certain difference existed between herb and shrub communities in stands of gap and non-gap. The similar coefficients were little correlative between gap area and communities. Gap was important to improve growth of herb and shrub and maintain species diversity of primitive subalpine fir forest in southwest Tibet.
    Relationships between water and productivity of seabuckthorn (Hippophae) in different habitats of the Loess Plateau, China
    WEI Yukun, LIANG Zongsuo, CUI Langjun, HAN Ruilian
    2004, (2):  195-200. 
    Asbtract ( 942 )   PDF (1320KB) ( 339 )  
    This paper deals with the relationships between water and productivity of seabuckthorn in different habitats of the Loess Plateau in north Shaanxi. The typical habitats were classified with hilltop, sunny, shady, semi-shady and semi-sunny hillside. The results showed that values of transpiration of five kinds of habitats were different, and transpiration of semi-shady was relatively stronger in the morning while others were weaker. With the variation of directions of sunshine, transpiration of shady and sunny was declining and meanwhile transpiration of hilltop was steady. transpiration of semi-shady reached the peak in 12:00. In the afternoon, these values of transpiration all reduced in different extents except seabuckthorn of shady, especially semi-shady. The mean transpiration of 5 habitats was ordered in semi-shade >shade >semi-sunny >hilltop >sunny. There were remarkable difference between diffuse resistance and transpiration, and same relationship was found between relative humidity and transpiration. But this relationship was not found between light intensity and transpiration. Different habitats had different productivities, and productivity of seabuckthorn in shade habitat was higher than those in other habitats.
    Response of stomatal characteristics and its plasticity to different light intensities in leaves of seven tropical woody seedlings
    CAI Zhiquan, QI Xin, CAO Kunfang
    2004, (2):  201-204. 
    Asbtract ( 1274 )   PDF (1828KB) ( 542 )  
    Stomatal characteristics and its plasticity in leaves of four canopy species, Shorea chinensis, Pometia tomentosa, Anthocephalus chinensis, Calophyllun polyanthum and three middle-layer species, Barringtonia pendula, Garcinia hanburyi, Horsfieldia tetratepala acclimated to different light conditions (8%, 25%, 50% and 100% of full sunlight) for more than one year were surveyed. All plant's stomata were distributed on the abaxial of leaves. Pometia tomentosa and Barringtonia pendula had higher stomatal density, and the guard cell length of Anthocephalus chinensis and Calophyllun polyanthum were much greater than others'. Stomatal density and stomatal index (ratio of stomatal numbers to epidermal cell number) were increased with growth irradiance increased, while numbers of stomata per leaf were higher in the low than the high relative PFD, and stomatal conductance of leaves was the highest in the 50% of sunlight except for Anthocephalus chinensis. The relative PFD had little effects on the guard cell length of all seven plants. There was a significant negative correlation between stomatal density and leaf area, but the stomatal conductance was not significantly positive with the stomatal conductance in some degree. The analysis of phenotypic plasticity of stomatal characteristics showed that plasticity index for stomatal index and numbers of stomatal per leaf were similar for canopy and middle-layer species, while the plasticity index of stomatal density and stomatal conductance were significantly greater for canopy species than middle-layer species. The high plasticity of canopy species was consistent with the hypothesis that specialization in a more favorable environment increases plasticity.
    Comparative study on daily change of photosynthesis rate of the rhizomatous grasses in milky ripe stage
    HE Wenxing, YI Jin, LI Hongmei
    2004, (2):  205-209. 
    Asbtract ( 931 )   PDF (1408KB) ( 352 )  
    Comparative study on daily change of photosynthesis rate of the rhizomatous grasses in their milky ripe stage was carried out, and the results showed that photosynthetic rate of five grasses appeared to be two-apex curve, except Elytrigia intermedia appeared to be one-apex curve. The general trend was that the higher the root/shoot ratio was, the later the first apex of the photosynthetic rate reached, and the shorter the noon break period was. Moreover, low relative humidity and high leaf temperature were the important factors for noon break. Leymus chinense, Pascopyrum smithii Rydb. cn. Rosana, Leymus secalinus, Leymus racemosus, Agropyron mongolicum and Elytrigia intermedia reached the first apex at 10:12, 10:00, 9:51, 9:39, 9:06 and 8:13, the noon break period was 471, 474, 464, 467 and 551 min, and the average leaf temperature during noon break was 37.8, 37.5, 36.9, 37.0 and 36.3 ℃, respectively. Leymus chinense and Agropyron mongolicum, Leymus secalinus and Leymus racemosus had similar daily change in photosynthetic rate, respectively, and their r values were 0.88 and 0.96 respectively when R=0.01.
    Simplification of crop shortage water index and its application in drought remote sensing monitoring
    LIU Anlin, LI Xingmin, HE Yanbo, DENG Fengdong
    2004, (2):  210-214. 
    Asbtract ( 869 )   PDF (1392KB) ( 348 )  
    Based on the principle of energy balance, the method for calculating latent evaporation was simplified, and hence, the construction of the drought remote sensing monitoring model of crop water shortage index was also simplified. Since the modified model involved fewer parameters and reduced computing times, it was more suitable for the operation running in the routine services. After collecting the concerned meteorological elements and the NOAA/AVHRR image data, the new model was applied to monitor the spring drought in Guanzhong, Shanxi Province. The results showed that the monitoring results from the new model, which also took more considerations of the effects of the ground coverage conditions and meteorological elements such as wind speed and the water pressure, were much better than the results from the model of vegetation water supply index. From the view of the computing times, service effects and monitoring results, the simplified crop water shortage index model was more suitable for practical use. In addition, the reasons of the abnormal results of CWSI>1 in some regions in the case studies were also discussed in this paper.
    Phosphorus translocation and distribution in intercropping systems of soybean (Glycine max) and citrus (Citrus poonensis)
    ZHOU Weijun, WANG Kairong, LI Hesong
    2004, (2):  215-220. 
    Asbtract ( 976 )   PDF (328KB) ( 298 )  
    A field mini-plot experiment was conducted on clay loamy oxisol using 32P trace technique when P fertilizer was applied in three depth soil (15, 35 and 55 cm soil layer) to compare P absorption, distribution and translocation in plant organ and soil profile under soybean and citrus monoculture and intercropping at Taoyuan Experimental Station of Agroecosystem Research of Chinese Academy of Science. Total P uptake (PT) and P accumulation in different parts (PA) of soybean were remarkably decreased under intercropping. When 32P was applied in topsoil (15 cm soil layer), 32P uptake ( 32PT) by soybean was significantly lower in intercropping than in monoculture. Whereas 32PT uptake by soybean was significantly greater in intercropping than in monoculture when 32P was applied in deep soil layer (35 cm or 55 cm soil layer). However, considerable difference was not observed for 32P translocation and distribution among soybean organs. 32PT uptake by citrus was much lower under intercropping than under monoculture. The P uptake by citrus newly could be transferred rapidly to aboveground and prior to active growing organ. Intercropping did not affect 32P distribution in citrus organ, but when P was applied in deep soil layer, the speed of 32P transferred to aboveground and active organ was slowed down. P mobility was strengthened in soil profile, and P of deep soil layer was promoted to move to topsoil in intercropping. The experimental results showed the optimal depth of applied P should be within 20 cm soil layer in soybean-citrus intercropping system.
    Effects of peanut mixed cropping with different gramineous plants on apoplast iron accumulation and reducing capacity of peanut.
    ZUO Yuanmei, ZHANG Fusuo
    2004, (2):  221-225. 
    Asbtract ( 927 )   PDF (636KB) ( 335 )  
    The effects of peanut mixed cropping with five different gramineous plants on apoplast iron accumulation and reducing capacity of peanut were investigated by soil culture experiment. The results showed that mixed cropping of maize, barley, oats, wheat, and sorghum with peanut could improve iron nutrition of peanut respectively. The phytosiderophores excretion rate of barley, oats and wheat were much higher than that of maize, and the phytosiderophores excretion rate of sorghum was lower than that of maize. In comparison with peanut in monocropping, the iron content in different organs of peanut mixed with maize, barley, oats, wheat and sorghum were increased. The Fe content in root apoplast of peanut mixed with five different gramineous was gradually increased and higher than that of peanut in monocropping at different growth days. At the same time, the mixed cropping systems remarkably improved the soil Fe availability in the rhizosphere and root Fe reducing capacity of peanut. The higher root Fe (Ⅲ) reducing capacity and much more available Fe in the rhizospe (Ⅲ) of peanut in mixed cropping played an important role in improving iron nutrition of peanut.
    Accumulation pattern of dry matter, nitrogen, phosphorus, potassium and silicon in rice genotypes and their relationships
    JIANG Ligeng, GAN Xiuqin, WEI Shanqing, XU Jianyun, CAO Weixing
    2004, (2):  226-230. 
    Asbtract ( 1147 )   PDF (669KB) ( 383 )  
    The accumulation of dry matter, nitrogen, phosphorus, potassium and silicon in 30 rice genotypes and their relationships under field condition were studied. The results showed that dry matter accumulated at ripening stage linearly increased with increase of nitrogen, phosphorus, potassium and silicon accumulation with highly significant correlation coefficients at both early and late season. At the same time, balance of nitrogen, phosphorus, potassium and silicon accumulation was beneficial for dry matter accumulation, which linearly increased with increase of nutrient balance index and decreased with increase of nutrient deviation index. The nitrogen, phosphorus, potassium and silicon were accumulated at the rate of 3.76:1:4.55:7.10 at early season and 2.88:1:4.54:8.09 at late season. During growth period, dry matter accumulation was the highest at middle stage, then late stage and early stage. But nitrogen accumulation was the highest at early stage, then middle stage and late stage. The dry matter accumulated before heading was mainly distributed in stem and leaf sheath, with the highest ratio of stem and leaf sheath to total dry matter at heading stage. In contrast, nitrogen accumulated before heading was mainly distributed in leaf blade, and the ratio of nitrogen in leaf blade to total nitrogen was higher than that of dry matter at either growth stages. Dry matter, nitrogen, phosphorus accumulated at ripening stage were mainly distributed in panicle with rates of 58.01%,66.42% and 70.06%, respectively. But potassium accumulated at ripening stage was mainly distributed in stem and leaf sheath with the rate of 62 08%. Silicon was largely distributed in stem and leaf sheath at early season with the rate of 43.11%, but distributed largely in panicle at late season with the rate of 46.99%.
    A dynamic knowledge model for wheat target yield design and variety selection
    ZHU Yan, CAO Weixing, DAI Tingbo, JIANG Dong
    2004, (2):  231-236. 
    Asbtract ( 864 )   PDF (385KB) ( 282 )  
    Based on integrating the effects of yield potential of photosynthesis and temperature, average yield level of last three years, soil fertility, fertilization and water management level and production technology level on yield increment, the dynamic yield increment index was quantified and a wheat knowledge model for design of target yield under different temporal and spatial environments was developed through knowledge engineering and system analysis method. By quantitatively calculating suitability of variety characteristics to environmental conditions and production requirements, a knowledge model for variety selection was established. Case studies on the target yield design with the data sets of five different eco-sites, three climatic years and average yield levels of last three years, two soil fertility levels and three fertilization and water management levels, and on suitable variety selection models with the data sets of five different eco-sites, normal climatic year and fifteen typical varieties indicated a good performance of the model system in decision-making and wide applicability.
    Microbial eco-characterization and its restoration in copper reclaimed wasteland in red soil area of China Ⅱ. Effects on soil microbial characteristics and community structure
    LONG Jian, HUANG Changyong, TENG Ying, YAO Huaiying
    2004, (2):  237-240. 
    Asbtract ( 903 )   PDF (1124KB) ( 354 )  
    Soil microbial features in Lipu copper mining and non-mine soil were studied comparatively. The results indicated that mine soil possessed obviously different microbial features such as lower microbial biomass carbon and soil basal respiration strength, Cmic/Corg decreasing, and higher microbial ecophysiological parameters qCO2, indicating that heavy metal had a depressive impact on soil microbial eco-characteristics. Biolog data showed that mine soil microbial community structure was changed obviously, the speed and quantity of carbon consuming were increased significantly, and the kinds of carbon sources which soil microorganism used were changed, led to consume much more energies for maintaining the normal needs of its life. But the utilization efficiency was lower compared with the control. All the results showed that soil microbial eco-characteristics could be used as a sensitive, effective and liable index of mine soil environment qualities.
    Modification and its application of generalized Schumacher model
    HONG Wei, WU Chengzhen, YAN Shujun
    2004, (2):  241-244. 
    Asbtract ( 1009 )   PDF (1484KB) ( 276 )  
    Based on the concrete analysis on growth equations presented by others, a modified Schumacher growth equation was proposed as, which included Gompertz function, Schumacher equation and generalized Schumacher equation, and had stronger self-adaptability and practicality. The analytic character and adaptability of the modified Schumacher equation were analyzed. According to the genetic algorithms method, this model was used to fit the growth data of endangered plant of Tsuga longibracteata and Platycladus orientalis. The results showed that the modified Schumacher equation was not only better than Schumacher equation and generalized Schumacher equation significantly, but also better than classical Logistic model and Li's self-adaptive model. So it could be used to study the dynamics simulation for tree growth and dynamics law for population growth.
    Problems in development of agriculture-animal husbandry ecotone and its countermeasures
    BAOYIN Taogetao, BAI Yongfei
    2004, (2):  245-248. 
    Asbtract ( 927 )   PDF (524KB) ( 273 )  
    Problems in development of Duolun, a typical agriculture-animal husbandry ecotone, and its countermeasures were discussed in this paper. Economic structure was not rational in Duolun, and it should develop industry and commerce, limit the scope of agriculture and animal husbandry, and actively increase efficiency of agriculture and animal husbandry. The structure of land use was not rational, and the main countermeasures were to increase area of forestland and grassland, and decrease cultivated area. On resources use, the main countermeasures were to exploit water resource rationally and bring into play resource superiority of mutually benefits on agriculture and animal husbandry. The ecological environment construction was the foundation of the national economy for sustainable development in agriculture-animal husbandry ecotone.
    Analysis on the dynamics of desert-oasis vegetation in the Sangong River Basin
    ZHAO Chengyi, SONG Yudong, WANG Yuchao, JIANG Pingan
    2004, (2):  249-254. 
    Asbtract ( 923 )   PDF (2091KB) ( 329 )  
    Taking the Sangong River Basin as a typical research area, the relationships between the change of landscape pattern of desert-oasis and the dynamics of vegetation were studied in this paper, and the evolution of the landscape pattern of desert-oasis was also discussed. The results showed that the main characteristics of landscape pattern were the dynamics of vegetation. It had the impact on the vegetation by the changes of topography, water resources using, corridor of river and drainage channel. It was shown the great variability for the height, cover and biomass of vegetation with the change of landscape pattern. Taking the corridor of river as the center, it usually showed a zone distribution from inside to outside for the desert-oasis landscape pattern. The vegetation types evolved from the tree-shrub mixed forest, thicket meadow, salinized meadow to desert with the change of the condition of water and heat in the basin. The stability of natural patch was higher than that disturbed by mankind or manmade patch. Usually, the stability of each patch was in order of desert>sandy land>urban>pond>paddy field>grass land>vegetable plot>woodland>residential area>saline-alkali land>wasteland>farming land>orchard. The landscape pattern of desert-oasis in the research area was developed by human activities based on natural oasis.
    Establishment and growth of Lolium multiflorum for phyto-remediation of Pb/Zn tailings
    JIAN Shuguang, YANG Zhongyi, JIAN Weijun
    2004, (2):  255-260. 
    Asbtract ( 995 )   PDF (388KB) ( 293 )  
    Following the cropping of Sesbania rostrata, Lolium multiflorum was cropped as the subsequent species on an acidified Pb/Zn tailings site. As the experimental treatments, S.rostrata issues harvested on the site were removed from the site or buried into the tailings as the green manure. Changes of tailings chemical and physical properties, germination, growth and heavy metal accumulation of Lolium multiflorum were investigated. The results showed that cropping of S.rostrata improved the chemical and physical properties of the tailings, especially for the contents of organic matter, total nitrogen, available phosphorus and available potassium. The strong acidity (pH<3) in the Pb/Zn tailings was the main factor that limited the establishment of L.multiflorum.The tailings acidity was decreased temporarily by lime application and it seemed to be helpful only for the germination because the strong acidity was restituted in the end of the experiment. In the most cases,L.multiflorum succeeded to germinate, grow and establish on the Pb/Zn tailings, and yielded relatively great biomass (DM 1.4～3.2 t·km-2). Compared to CK (without S.rostrata cropping), cropping S.rostrata increased the biomass of subsequent L.multiflorum by 4.8%～39.5% in case without S.rostrata green manure using and by 7.7%～139.5% in case with the green manure using, and the green manure application resulted in 2.7%～75.8% increment of L.multiflorum biomass. The results proved that the artificial vegetation process using S.rostrata and subsequent L.multiflorum would be a successful pioneer stage for restoration of the Pb/Zn tailings.
    Effects of different light transmission rate on American ginseng's photosynthesis
    LI Wanlian, WAN Zhihu, YANG Shuyun
    2004, (2):  261-264. 
    Asbtract ( 1009 )   PDF (496KB) ( 319 )  
    From 1997 to 1998, series of experiments were carried out to study American ginseng's photosynthesis related to light transmission rate of plastic cover. The results showed that American ginseng's light saturation point for photosynthesis was different under the different light transmission rate (LTR) because of shading. At about 29 0℃ and under 12%, 30%, 42% LTR, 4-year-old American ginseng's light saturation point were 171 0, 323 0, and 429 0 μmol·m-2·s-1, respectively. The maximum net photosynthesis rate (Pn) was 6.54 mg CO2·dm-2·h-1, which appeared under the shading of 30% LTR. The daily course of 3-year-old American ginseng's Pn changed with LTR. When LTR was less than 25.8%, the daily curves of Pn had a single peak, and when LTR was higher than 25.8%, it had two peaks and the leaf's photosynthesis noon break phenomenon was remarkable. The results of single correlative analysis showed that the dominant factor that influenced Pn was photon flux density (PFD), and the results of plural regression analysis showed that the synthetic effect of all the influencing factors together on Pn was significant.
    Vertical distribution character of nutrient elements in peat of Sanjiang Plain
    YU Junbao, WANG Jinda, LIU Jingshuang
    2004, (2):  265-268. 
    Asbtract ( 884 )   PDF (399KB) ( 292 )  
    Based on the methods of sampling in winter and dividing soil layer on the site, the vertical distribution character of normal amount nutrient elements N, P, Mg, Ca, Fe and nutrient trace elements Cu, Zn, Mn, B in peat of river bed-flood land and valley depression land in the Sanjiang Plain was studied systematically. The results showed that TN was accumulated in surface layer of peat, and TP was accumulated in root layer. The contents of TN and TP were decreased with the section depth increasing. Zn, Mn, B, Mg and Fe were gathered in root layer and accumulated sharply in gley horizon of silt sub-clay, and the content of Ca was regular relatively in each layer of section. There were close correlations among some nutrient elements in peat section.
    Spatial pattern analysis of forest landscape in low coteau of Middle Qilian Mountains
    YANG Guojing, XIAO Duning
    2004, (2):  269-272. 
    Asbtract ( 953 )   PDF (1705KB) ( 418 )  
    Based on the vegetation map and the relief map, using GIS and Fragstats, the spatial pattern of forest landscape of Xishui reserve in Qilian Mountains were analyzed. The results showed that the distribution of the vegetation was impacted mostly by altitude and aspect, grassland was mostly distributed on the land of altitude 2 500～2 900 m and aspect of south and southwest,Picea crassifolia forest was always in the land of altitude 2 900～3 300 m and aspect of north, northeast, east and northwest, and shrubbery was in the land of altitude 3 300～3 700 m. The grassland had the biggest area and its connectivity and integrality were the best. The biggest MPFD of Picea crassifolia forest meant that its shape was the most complicated, its mean patch area was small, and the distance between the patches was short. So Picea crassifolia forest was easy to be impacted by some disturbance. The forest suitable land and Sabina przewalskii forest showed more outstretched characteristics than farmland and land with few trees. The mean nearest-neighbor distance of the poplar forest was the biggest in all the landscape elements, so the poplar forest's fragmentized degree was the highest in all the landscape elements.
    Analysis of the landscape diversity dynamics of small watershed in the Loess Plateau
    WANG Xiaoyan, XU Zhigao, YANG Mingyi, TIAN Junliang
    2004, (2):  273-277. 
    Asbtract ( 947 )   PDF (1070KB) ( 253 )  
    Taking Zhifanggou Gully as the study area, some landscape diversity indexes were attained under the support of GIS technology. Utilizing the indexes such as patch size, average fractal dimension, diversity index, dominance, evenness, fragmentation and conglomeration, the changes of landscape diversity in the small watershed in Loess Plateau during the past 40 years were studied. The landscape diversities had been increasing for the recent 40 years due to the effect of both human activity and plants' endogenesis succession. The patches number increased, and the dryland matrix was substituted gradually by other matrixes such as meadow and woodland. The landscape pattern trended to be fragmentized and the indexes of landscape type diversity and evenness increased, while landscape diversities changed greater during 1978～1998 than during 1958～1978. Homogeneous dryland matrix landscape ecosystem in 1958 had already changed into heterogeneous meadow and woodland matrix landscape ecosystem, which had greater structure stability and stronger function than before.
    Distributed modeling of nutrient transport in basin with support of remote sensing and geography information system
    LI Shuo, SUN Bo, ZENG Zhiyuan, ZHAO Qiguo
    2004, (2):  278-282. 
    Asbtract ( 1042 )   PDF (566KB) ( 371 )  
    Agricultural non-point source pollution has become serious in our country. Modeling the processes of nutrient(especially nitrogen and phosphorus) transport in basin and evaluating the adopted management practices are important for controlling the impact of non-point pollution on environment. A research scheme for distributed simulation of nutrient transport processes in Lianshui Basin, Xingguo County, Jiangxi Province was designed, with the support of remote sensing (RS) and geography information system (GIS). The research procedure included model selection, discretization and spatial parameterization of the basin, prediction, and validation. SWAT model was selected, and basin-subbasin-hydrological response unit discretization scheme was designed. Supported by RS and GIS and based on the topographic features of the watershed, the subwatershed discretization divided the watershed into subbasins, and each subbasin could be further partitioned into multiple hydrologic response units (HRUs), which were unique soil/land use combinations within the subbasin and modeled through statistical spatial overlay analysis. The parameters of land use were obtained from the supervised classification of TM imagery based on field training samples, and those of soil were obtained from field sampling and further interpolated through geostatistical method. The simulation was carried out by using the data from 1991 to 2000. The results showed that the simulation accuracy of annual runoff water yield and sediment yield was 89.9% and 70.2%, respectively.
    Spatial distribution and landscape ecological impact degree assessment of quarry in Zhuhai City
    WU Zhifeng, WANG Jizeng, ZHUO Muning, WAN Hongfu
    2004, (2):  283-286. 
    Asbtract ( 926 )   PDF (351KB) ( 269 )  
    Artificial erosion is one of the typical artificial landscape degradation. Based on the support of GIS and RS and combined with field investigation data, the spatial distribution characteristics and landscape ecological impact degree of quarry were analyzed. There were 235 quarries in Zhuhai city, which concentrated on Sanzao town and Jingan town. According to buffer analysis, the quarries distribution had a obviously logarithm relationship with its distances from roads. 152 quarries with the area of more than 5000 m2 were assessed by landscape ecological impact degree (LEI) index. The results indicated that 9 quarries belonged to great influence level and 19 quarries belonged to strong influence on ecological environment.
    Distribution and stock of mercury in typical wetland plant in the Sanjiang Plain
    LIU Ruhai, WANG Qichao, LU Xianguo, LI Zhibo, WANG Yan
    2004, (2):  287-290. 
    Asbtract ( 997 )   PDF (276KB) ( 288 )  
    Total mercury concentration of typical wetland plant was analyzed. There were great difference in mercury content among different plants, and the order was moss > alga > carex > herb > shrub. There was a trend of increasing total Hg concentrations from vascular plants to bryophytes, and from dry to wet site. The wetland soil was the source of mercury in the air close to the ground, so it influenced the content of mercury in the plant. In different components of plants, mercury contents were in the order of dead stand > root > leaf > stem. Mercury concentration increased in initial stage and decreased in the end of the growing season. According to the mercury content and biomass, the mercury stock of plant were calculated, and it was 24 9 μg·m-2 in the above ground of plant in Calamagrostis angustifolia wetland and 35 8 μg·m-2 in Carex lasiocarpa wetland.
    Difference of lead uptake and distribution in rice cultivars and its mechanism
    LIU Jianguo, LI Kunquan, ZHANG Zujian, LU Xiaolong, YU Biyu, CAI Yixia, YANG Jianchang, ZHU Qingsen
    2004, (2):  291-294. 
    Asbtract ( 930 )   PDF (1125KB) ( 341 )  
    In order to investigate the uptake of lead by rice plant and the distribution of lead in different parts of rice, pot experiment was conducted with 20 rice cultivars of different genotypes by adding lead to soil. The results showed that there existed significant differences among the cultivars in the lead uptake and distribution by rice plants, but the differences had no obvious relationship with rice genotypes. The lead concentrations decreased rapidly from roots to grains along rice plants, so the concentrations of lead were very low in grains compared with other parts of rice plants. The regression analysis showed that there were significant negative correlations between adjacent organs of rice plant, but positive correlations, mostly significant, between disconnected organs, for the lead concentrations in them. Lead concentration in the leaf of heading stage showed a significant positive correlation with that in the grain of ripening stage. Lead was not distributed uniformly in different parts of grain structure, and the lead accumulation in polished rice was only 32.88% of the total lead accumulation in grain.
    Degradation of methyl parathion in soil and Chinese chive by strain DLL-1
    ZHANG Ruifu, JIANG Jiandong, CUI Zhongli, LI Shunpeng
    2004, (2):  295-298. 
    Asbtract ( 1031 )   PDF (630KB) ( 283 )  
    Degradation of methyl parathion in soil and Chinese chive by strain DLL-1 was studied. Usage of methyl parathion at 7.5, 15, and 22.5 kg(a.i.)穐m-2 resulted in the average amount of residue of 0.663, 1.270, and 1.901 mg穔g-1 in Chinese chive respectively. The natural degradation rate was 98.94%, 96 44%, and 96.04% corresponding to the 3 levels of usage. The amount of pesticide residue could be significantly decreased through the application of high effective degrading microbial agents. The amount of pesticide residue in Chinese chive and soil was 0.269 and 0.099 mg穔g-1 with the usage of 75 kg穐m-2 of degradation bacterium, which was decreased by 78.82% and 98.68% compared with the control. Increasing the bacterium usage led to the increase of degradation rate. Usage of degradation bacterium more than 75 kg穐m-2 did not increase the degradation rate further. The best time of the application of the degrading microbe was 3 days after the application of the pesticide.
    Host plant suitability and reproductive isolation of two Schizotetranychus bambusae populations from the bamboo species Phyllostachys pubescens and Neosinocalamus affini
    LIU Huai, ZHAO Zhimo, DENG Yongxue, DENG Xinping, HE Lin, WU Shiyuan, SHUAI Xia
    2004, (2):  299-302. 
    Asbtract ( 1006 )   PDF (165KB) ( 279 )  
    Development, survivorship, reproduction and procreation isolation of Schizotetranychus bambusae from the bamboo species Phyllostachys pubescens and Neosinocalamus affinis reared on different host plants were evaluated in laboratory. The results showed that the population of S.bambusae from Phyllostachys pubescens (PhS) failed to complete its life cycle when reared on the leaf of N.affinis. When the population of S.bambusae from N.affinis (NeS) was reared on the leaf of P.pubescens, the survivorship and fecundity decreased. The rm, λ and Ro were 0.0391, 1.0399 and 2.5542, respectively. At 27℃, when the PhS was reared on P.pubescens, rm, λ and Ro were 0.1415, 1.1520, and 15.6298, respectively, whereas NeS was reared on N.affinis,rm,λ, and Ro were 0.0993, 1.1044, and 10.0622, respectively. Reciprocal cross test between PhS and NeS showed that the two populations could mate, but laid unfertilized eggs that produced male only, indicating the existence of reproductive isolation.
    Cooperative effect of Spodoptera litura nuclear polyhedrosis virus with parasite wasp, Microplitis sp. on the S.litura larvae
    JIANG Jiexian, JIANG Zhurui, LEI Runhua
    2004, (2):  303-307. 
    Asbtract ( 1034 )   PDF (352KB) ( 231 )  
    The relationship between the survival rate, developmental duration of Microplitis sp. in Spodoptera litura larvae and time of exposure of the host larvae to virus, the inoculation virus concentration were investigated to determined if parasites which emerged from virus-infected S.litura larvae had normal survive, and if the parasites could sever as the vector for S.litura nuclear polyhedrosis virus (SlNPV). There was no significant difference in time that parasites spent in virus-infected larvae and healthy one, indicating the SlNPV did not affect the developmental period of Microplitis sp. Parasite larvae in hosts exposed to virus after parasitization compmeted their development before their hosts died of virus infection. The proportion of parasites survived varied with the inoculation virus concentration and the time of exposure of the host larvae to virus, the percent of parasites survived increased as the time between host parasitization and host virus exposure increased, and decreased as the inoculation virus concentrations increased. The female parasites which developed or oviposited in virus-infected hosts, and manually contaminated the ovipositor of the females with virus suspension could all carry infective doses of the virus, and transmit virus from infected larvae to healthy one through ovipositor. A female parasite which developed or oviposited in virus-infected hosts transmitted infective doses of the virus to an average of 2.14, 2.45 healthy host larvae exposed to it respectively. A female parasite from the cocoon contaminated with SlNPV of different virus concentration could transfer infective doses of the virus to an average of 1.45 healthy host larvae.A female parasite exposed to the mixture of different virus concentration and 10% honey-water solution could also transmit virus to an average of 0.94 larva.
    Population dynamics of Microtus fortis in Dongting Lake region and its forecasting
    WANG Yong, GUO Cong, ZHANG Meiwen, LI Bo, CHEN Anguo
    2004, (2):  308-312. 
    Asbtract ( 1048 )   PDF (265KB) ( 221 )  
    The population dynamics of Microtus fortis in Yueyang, Hunan Province was studied from 1991 to 1996. M. fortis lived on the beach of the lake from early autumn to next spring, but moved to the farmland in summer when the beach was flooded. When lived on the beach, its population increased gradually. Usually, M. fortis made great damage on the crops when moved to the farmland. The population dynamics of M. fortis was different on the beach and on the farmland, and the key affecting factors were also different. Lake beach was the most suitable habitat for M. fortis. When it emerged in autumn, M. fortis moved back on it. The main breeding season of M. fortis inhabited on the beach was from October to May, and its population density increased gradually. The period between the beach emerged and been flooded determined the population size of the animal moved to farmland. Another factor was the rainfall in March. Farmland was not the suitable habitat for M. fortis. Because of the low breeding potential, high mortality and dispersal on farmland, its population density kept decreasing, and was very low in winter. The population density on farmland dropped dramatically when the lake beach emerged. The animal population was forecasted by means of regression analysis, and a linear regression equation was obtained. The predicted values matched with the real population densities of the animal in the field.
    Suspending particulates in rotifer-culturing pond ecosystem
    ZHAO Wen, LI Xiaodong, ZHAO Zhenxing, LIU Qing
    2004, (2):  313-315. 
    Asbtract ( 987 )   PDF (176KB) ( 249 )  
    A comparative study on the structure and dynamics of suspending particulates in static and current water rotifer-culturing ponds showed that the total content of suspending pariculates varied from 6.76 to 65.39 mg稬-1, with an average of 11.50 mg稬-1 in static water ponds, among which, organic pariculates accounted for 66.8%, while inorganic particulartes occupied 33.2%. In the organic pariculates, both particulate detritus and bacteria accounted for 31%, while phytoplankton and zooplankton occupied 30.5% and 5.3%, respectively. The amount of suspending pariculates in current water ponds was 41.83 mg稬-1 in average, among which, organic pariculates accounted for 70.4%, while inorganic pariculates occupied 29.6%. In the organic pariculates, both particulate detritus and bacteria accounted for 39.2%, while phytoplankton and zooplankton occupied 30% and 1.2%, respectively. The content of suspending pariculates in static water ponds was less than those in current water ponds. Rotifer-culturing pond was a special type of ecosystem, where Brachionus plicatilis was the major consumer, its community structure was sample, and the abiotic factors were easy to be changed, which resulted in the dynamics of suspending pariculates content in ponds. The ratio of organic to total pariculates in rotifer-culturing ponds was higher, and the contents of both particulate detritus and bacteria were corresponding to that of plankton.
    Methodology of enacting standards for remediation of contaminated soils
    ZHOU Qixing
    2004, (2):  316-320. 
    Asbtract ( 1001 )   PDF (1841KB) ( 850 )  
    Remediation technology for contaminated soils is being developed rapidly in recent years. However, there is a hysteresis in enacting remediation standards for contaminated soils. In particular, no corresponding research has been done in China. Methodology of enacting standards for the remediation of contaminated soils is discussed in order to promote the work in this field. It is emphasized that technological cleanup levels including limits of detection, environmental background levels and regulatory cleanup levels should be fully considered in the enactment of remediation standards.
    Research advance in ecotoxicology and environmental impact of veterinary medicines
    DIAO Xiaoping, SUN Zhenjun, SHEN Jianzhong
    2004, (2):  321-325. 
    Asbtract ( 979 )   PDF (627KB) ( 464 )  
    Veterinary medicines or their metabolites could be discharged to the environment through different exposure routes, and had potential impacts to ecosystem in different levels, including individual, population, community and ecosystem. Their fate and potential impact have been widely researched in the world. This paper reviewed their exposure routes, fate in the environment, and impact on organisms in soils and waters and on soil processes. The significance of their environmental risk assessment was also analyzed.
    Influence of dissolved organic matter (DOM) on environmental behaviors of organic pollutants in soils
    LING Wanting, XU Jianmin, GAO Yanzheng, WANG Haizhen
    2004, (2):  326-330. 
    Asbtract ( 1373 )   PDF (980KB) ( 883 )  
    Dissolved organic matter (DOM) is an important component of solutions in terrestrial and aquatic ecosystems through its influence on acidity, nutrient availability, and toxicity. DOM could enhance the apparent solubility of organic pollutants and alter adsorption-desorption equilibrium of organic pollutants on soil. The enhancement of organic pollutants desorption in the presence of DOM could facilitate the mobility of organic pollutants in soil. On the other hand, the sorption of DOM by solid sorbents in soil could also enhance the retention of DOM-associated organic pollutants in soil. Furthermore, as a photosensitizer, DOM could promote the photogradation of organic pollutants in soil. And under certain condition, DOM also affected the hydrolysis of organic pollutants in soil solution. The effects of DOM on environmental behaviors of organic pollutants in soils were related to the physico-chemical characteristics of organic pollutants, DOM, and soil.
    Physiological adaptations of Sichuan golden monkeys (Rhinopithecus roxellana)to high altitude habitat in the Qinling Mountains
    GAO Yunfang
    2004, (2):  331-334. 
    Asbtract ( 946 )   PDF (240KB) ( 343 )  
    The golden monkey (Rhinopithecus roxellana) is a special species in China, and possesses the highest altitude habitat (4 167 m) in all kinds of primates. So it is very important to study this monkey how to adapt to such a high and severe habitat. According to our research results in recent years and relative publications, this paper, from digestive, respiratory, blood, circulative and reproductive systems, inquired into the Sichuan golden monkey (Rhinopithecus roxellana), a named species for golden monkey, how to adapt to the high altitude habitat in the Qinling Mountains and what was the mechanism of these adaptations.
    Conservation tillage systems in North America and their significance for China
    YANG Xueming, ZHANG Xiaoping, FANG Huajun, LIANG Aizhen, QI Xiaoning, WANG Yang
    2004, (2):  335-340. 
    Asbtract ( 973 )   PDF (1408KB) ( 491 )  
    Soil degradation through erosion and desertification reduces soil productivity, and is a serious problem in agricultural production of China. To avert our arable land from further degradation, soil management must be shifted from degrading tillage to conservation practices. Over viewing the technology used in the 20th century for controlling soil degradation from erosion, conservation tillage developed in the United States and adopted in South America and Africa is one of the most successful measures to overcome soil degradation problems. This paper reviewed the historical development and the current situation of conservation tillage systems used in North and South America, with special reference to their effects on soil erosion control and soil quality. The increasing adoption of conservation tillage systems in North and South America and Africa followed an enhanced awareness of the increasing risk of soil erosion and the high cost of fuel associated with conventional tillage. Many crucial points for successfully adopting conservation tillage systems were emphasized, such as equipment/tool development and chemical weed control. Adopting conservation tillage could provide China with low-priced means of reducing soil degradation and improving soil and water quality.
    Impact of pesticides on biodiversity in agricultural areas
    WU Chunhua, CHEN Xin
    2004, (2):  341-344. 
    Asbtract ( 920 )   PDF (889KB) ( 658 )  
    Large amount application of pesticides caused a lot of ecological and environmental problems, among which, the impact of pesticides on biodiversity was most important. In this paper, an overview of the impacts of pesticides on biodiversity in agricultural areas, including the community structure of insects, populations of soil invertebrates and microorganisms, and plant communities was provided, and the reasonable use of pesticides and the measures of protecting biodiversity in agricultural areas were also put forward.
    Effects of rice volatile infochemicals on insects
    ZHOU Qiang, XU Tao, LUO Shiming
    2004, (2):  345-348. 
    Asbtract ( 975 )   PDF (1007KB) ( 298 )  
    Plant volatile is not only the key of the relationship among plant, herbivore and its natural enemy, but also the foundation for the theory and practice of pest manage. In this paper, the chemical characteristic of rice volatile and its function among herbivore and its natural enemy were reviewed. The application and development direction of rice volatile infochemicals were proposed. Two directions to study the rice volatile infochemicals, which could be used in pest control, were also discussed. One was the physiology and biochemistry of little molecule signals, which was the key of rice second metabolize, and the other was the base of sense, identify and learn of pest insect to rice volatile infochemicals.
    Forest health ecological risk assessment in China
    XIAO Fengjin, OUYANG Hua, CHENG Shulan, ZHANG Qiang
    2004, (2):  349-353. 
    Asbtract ( 829 )   PDF (1130KB) ( 317 )  
    Forest health ecological risk assessment is an important factor in forest resources management. In this paper, we selected forest fire, forest disease-pest disasters and acid rain as main risk sources, described the risk resources by probability, intensity and distributing, and mapped each risk source. The endpoints were the damages that the risk acceptor might and these damages might cause ecosystems' organization and function changing under the uncertainty risk sources. Endpoints of forest might compose of productivity descent, reducing biodiversity, forest degrading, forest ecological function declining, furthermore, forest disappearing. We described exposure in terms of intensity, space, and time. In the exposure and hazard analysis, we used fragile index to show frangibility or resistibility (resistibility is reverse to frangibility), and analyzed the damages by different risk sources. Risk assessment and management was the integrated phase of the research. Because of the spatial heterogeneity of risk sources, all risk index were overlaid in the China map by GIS, which divided the region into 30 ecological risk sub-zones (provinces), according to risk index of each risk sub-zone, and the forest in China was divided into six levels of risk zones. In every level of risk zones, we also put forward the countermeasures for forest health ecological risk management. The result of assessment could provide scientific basis for forest management.
    Application of artificial neural network based on the genetic algorithm in predicting the root distribution of winter wheat
    LUO Changshou, ZUO Qiang, LI Baoguo
    2004, (2):  354-356. 
    Asbtract ( 860 )   PDF (226KB) ( 233 )  
    In this study, a controlled experiment of winter wheat under water stress at the seedling stage was conducted in soil columns in greenhouse. Based on the data gotten from the experiment, a model to estimate root length density distribution was developed through optimizing the weights of neural network by genetic algorithm. The neural network model was constructed by using forward neural network framework, by applying the strategy of the roulette wheel selection and reserving the most optimizing series of weights, which were composed by real codes. This model was applied to predict the root length density distribution of winter wheat, and the predicted root length density had good agreement with experiment data. The way could save a lot of manpower and material resources for determining the root length density distribution of winter wheat.