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    25 December 2000, Volume 11 Issue 6
    Articles
    Relationship between light and regeneration character of Huangshan pine
    FU Songling, HUANG Chengling, CAO Hengsheng, WU Zemin
    2000, 11(6):  801-804. 
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    The growth and physiological characters of 1~3 years old Huangshan pine seedlings in pure and mixture plots with four different transparancy were determined,and the germination percentage of seeds and their complex stressing vigour were tested.Meanwhile,the regeneration mechanism of Huangshan pine in natural forest was studied in this paper.The results showed that the plumpness of seeds was 65%,the germination percentage was 27%,and the complex stressing vigour was 26%.The lower germination percentage affected the reproduction of Huangshan pine.The photosynthetic rate was more affected by solar energy,but less by humidity and surface temperature.With high light composation,Huangshan pine's regeneration under forest was difficult.The seedlings of Huangshan pine in mixed coniferous and broadleave tree plots were at a disadvantage because of slow growth and insufficient ligth.
    Impacts of forest and precipitation on runoff and sediment in Tianshui watershed and GM models
    OUYANG Hui
    2000, 11(6):  805-808. 
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    This paper analyzed the impacts of foret stand volume and precipitation on annual erosion modulus,mean sediment,maximum sediment,mean runoff,maximum runoff,minimum runoff,mean water level,maximum water level and minimum water level in Tianshui watershed,and also analyzed the effect of the variation of forest stand volume on monthly mean runoff,minimum runoff and mean water level.The dynamic models of grey system GM(1,N) were constructed to simulate the changes of these hydrological elements.The dynamic GM models on the impact of stand volumes of different forest types(Chinese fir,masson pine and broad leaved forests)with different age classes(young,middle aged,mature and over mature)and that of precipitation on the hydrological elements were also constructed,and their changes with time were analyzed.
    Articles
    Occurrence and control of frost in Tilia amurensis and Fraxinus mandshurica young plantations
    CHEN Xiangwei, ZHANG Yu, MA Hongbo
    2000, 11(6):  809-813. 
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    The changes of minimum temperature periodical biological phenomena and frost in yound Tilia amurensis and Fraxinus mandshurica plantation stands were systematically analyzed based on the vertical gradient observation and plot investigation.Meanwhile,the resistance of Tilia amurensis to late frost was also studied.The results showed that the phenophase of T.amurensis was later than that of F.mandshurica.Influenced by significant temperature inversions in this area,the phenophase of T.amurensis and F.mandshurica changed regularly in different aspects and slope positions.The sprouts on west slope started earlier than that on east slope.The higher they grew on the slope,the earlier they sprouted,with the earliest sprout at the top of slope.Late frost in this area only took place when the trees were sprouting, but air temperature decreased significantly at the same time.The degree of injury from the late frost could be controlled effectively by selecting suitable site.Sites down the slope,especially the east slope,were not suitable for T.amurensis and F.mandshurica plantation in this research area.Chemical treatment and biological shading could prevent late frost injury through putting off sprout.Mixed plantations could prevent F.mandshurica and T.anurensis from late frost injury significantly,and the frost injury index and the proportion of the tree number of different injury grades were lower than those in pure stands.
    Optimized models of logging-tending system in cutting areas
    GUO Jiangang, JING Yun, ZHANG Ruohong, XIONG Wenyu, SU Jinyun
    2000, 11(6):  814-818. 
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    The comprehensive advantages of different logging tending systems in Pinus massoniana forest cutting area were evaluated by set pair analysis,based on the comparison of their economic and ecological benefits.The results showed that the optimized model for P.massoniana forests in Northern Fujian comprised 40% selective cutting,manual skidding,clear cutting in ribbon,and natural regeneration with artificial aids,which could also be used in the nearby forests with conditions similar to the experimental area.
    Ecosystem management of settlement area in Xingshan County
    GUO Zhongwei, Li Dianmo
    2000, 11(6):  819-826. 
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    In the immigrant settlement area of Three-Gorges reservoir region in Xingshan County, Hubei Province,the ecological problems were the restoration of degraded ecosystem, rehabilitation of degraded crop land, and reconstruction of towns and villages. The key to the construction of the settlement area was reassigning the way of land use. The major aim of restoration of natural ecosystems should be to improve water conservation capacity of the land,because this area is located in the catchment of the Xiangxi River. The goals of management were determined as the coordinated development of both agricultural and natural forest ecosystems,the maintenance and increase of water conservation capacity of ecosystems,and the maintenance and extension of wildlife habitats.For the purpose of effective ecosystem management, the area was classified into four divisions of functional conservation region, functional rehabilitation, natural reserves and natural maintenance. The ecosystem management of the settlement area in Xingshan County was implemented in every land cell,using GIS and the typical grid-square survey method.The approach of multi-objects optimal spatial plan was developed in this paper,in which,special emphasis was put on the ecological, economic and social benefits in the construction of towns and villages. According to the scheme of management,the cover of forest in the settlement area,would increase by 30.19%, and water conservation capacity of the ecosystems would raise by 38.7%.
    Systematic analysis of agro-ecoclimatic resources in Gansu Province
    BAI Yongping
    2000, 11(6):  827-832. 
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    Based on the over years data from 86 meteorological stations in Gansu Province,the agro-ecoclimatic resources in this province was systematically analyzed.Resource indices Cr,efficiency indices Ce and utilization coefficient K were calculated by using the dynamic models of agro-ecoclimatic suitability degree.According to the average monthly efficiency indices Ce,the agro-ecoclimatic resources were divided into 7 types and 3 subtypes by fuzzy cluster.The potentiality matching condition and utility degree of agro-ecoclimatic resources showed the evident characteristic of spatial differentiation.Generally,the south was superior to the north,and the east was superior to the west in terms of these parameters,with the type of South Gansu Mountain much better than that of Hexi Corridor.Some suggestions about the exploitation and utilization of the agro-ecoclimatic resources in Gansu province were proposed.
    Cluster analysis methods appropriate for classification of drought-resistant wheat ecotypes
    CHAI Shouxi
    2000, (6):  833-838. 
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    The appropriate cluster analysis methods for classification of drought-resistant wheat ecotypes were investigated,based on the analysis of 21 morphologic and agronomic characters of 15 winter wheat cultivars. According to the proximity degree to the results from experts experiences,the cluster results using original data were orderly better than those using Varimax orthogonal rotation, Promax skew intersection rotation,and principal component analysis with phenotypic mean's correlation matrix. The results using Euclidean distance were greater than those using Mahalanobis distance.The clustering methods of correspondent analysis and fuzzy cluster were better than those of nearest distance, furthest distance or group average method (UPGMA).Among all cluster results from various methods combined,the two cluster results from the fuzzy cluster using original data and from the correspondence analysis method were closest to the results of experts' experience.Based on both comparisons of results and examination of the performance of different strategies with several statistical properties, the two methods mentioned above were also acceptable.
    A wintering habitat model for red crown crane
    LI Wenjun, WANG Zijian
    2000, (6):  839-842. 
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    A mathematical model was established based on GIS and RS to simulate and predict the habitat distribution of red crown crane(Grus japonensis) in Yancheng Biosphere Reserve,Jiangsu Province,China.The model was tested through calculating the match coefficience of observed and predicted presence/absence data,which was 72.63%,showing that the model could be used to reflect the habitat distribution of red crown crane.
    A method for designing buffer zone in Yancheng Biosphere Reserve:taking red crown crane as objective species
    LI Wenjun, WANG Zijian
    2000, (6):  843-847. 
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    Social,economic,ecological and geomorphic factors are needed to be considered when designing the buffer zone of natural reserve.In this paper,the Analytic Hierarchy Process(AHP) was applied to design the width of buffer zone.Under considerating the influences in different sections around the reserve,different widths of the buffer zone were designed,and a case study was carried out in Yancheng Biosphere Reserve.The results showed that the proposed method was reasonable and practicable in designing the buffer zone of nature reserve.
    Impact of starvation on predation by male adult Chrysopa septempunctata
    ZOU Yunding, LI Guiting, ZHOU Xiazhi, LIU Tongwen
    2000, (6):  848-850. 
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    The predation on Schizaphis graminum by male adult Chrysopa septempunctatata at various levels of starvation was examined in this paper.Th results showed that the functional reactive types of predator were not altered by its starvation duration,and the amount(Na) of catched S.graminum by C.septempunctata wihin 24hrs varied with duration time(t),which could be expressed by the model: Na=100/(1+e-0.3088-0.0996t).The relationship between predation rate(v) and time(x) could be described as v=6.7117x-0.7928.The male adult predators preferred feeding on the young preys.
    Articles
    Impact of high temperature on testicular growth and development of valuable silkworm Antheraea yamamai(Lepidoptera:Saturiidae)
    YE Gongyin, HU Cui, GONG He
    2000, 11(6):  851-855. 
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    The results indicated that high temperature had a significant impact on the growth and development of testis in Japanese oak silkworm Antheraea yamamai.The testicular size of the 3rd and 4th instar larvae increased within the range from 20 to 29℃,and slightly decreased at 32℃.While in the 5th instar,it decreased within the range from 20 to 26℃,with the biggest size at 20℃.The testis was almost hard to grow and develop because the larvae could not survive at 29 to 32℃.When the mature larvae were treated at 32℃ at the beginning of coconing or at the 1st or 6th day of pupating,the growth of testicular size and spermatogenesis were significantly arrested,and the sperm number and the content of soluble protein in the testis markedly decreased.When the male moth of the 1st day was treated at 32℃,the activity of the sperms in the testis obviously decreased,in contrast to the treatment at 20℃.It is concluded that for the egg raising of the silkworm,its mature larvae,puape in cocoons and male moths should not be exposed to 32℃ from cocooning to adult stage.The proper temperature for rearing 3rd,4th and 5th instar larvae was discussed.
    Lifetable of cotton bollworm under different control condition
    YANG Yizhong, PANG Xionfei, LIANG Guangwen
    2000, (6):  856-860. 
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    The lifetables of 3rd and 4th generation of cotton bollworm Helicoverpa armigera Hubner were established by action factors under four different control conditions.The results showed that under natural control,the egg parasitic rates of 3rd and 4th cotton bollworm were 4.39% and 1.19%,the predatory rates were 21.11% and 15.80%,and the larvae parasitic rates were 19.34% and 16.20% respectively.The indexes of population trend were only 0.0032 and 0.0014 respectively,after using selective pesticides IKI and Bt to control cotton bollworm.Though the index of population trend decreased to 48.66% and 61.67% after contantly praying chemical pesticides,the number of predators also decreaseed to 23.48% and 41.26% respectively.Transgenic Bt cotton could inhibit the population increase of cotton bollworm,but had no effect on predators.The parasitic rates of 3rd and 4th cotton bollworm on Transgenic Bt cotton were 51.14% and 0% respectively,as compared to control.
    Articles
    Effect of rice variety resistance on population dynamics of Nilaparvata lugens and Sogatella furcifera
    WANG Rongfu, ZHANG Chenglin, ZOU Yunding, LÜ Liang, CHENG Xianian
    2000, 11(6):  861-865. 
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    The effect of rice varieties with different insect resistance on dynamics of Nilaparvata lugens and Sogatella furcifera population was examined,based on the investigation of their inhabiting ratio,egg amount, survival rate of egg and nymph,nymph development,and the amount of their offspring population.Four rice varieties,TN1,N22,AsD7 and Ptb 33 were investigated.Ptb 33 had a significantly lower inhabiting ratio, egg amount,and survival ratio of eggs and nymphs of both parasitic populations,a prolonged development time from nymphs to adults,and an inhibited offspring population, indicating an evident resistance of this host variety.N22 and AsD7 inhibited the development of offspring S. furcifera and N. lugens, respectively.The parasitic populations of S. furcifera and N. lugens developed more rapidly on TN 1,compared with N.lugens population on N22 and S. furcifera on AsD7. The relationship between the quantitative dynamics of both population and rice variety replacement was discussed,and the possibility of using resistant rice varieties to control these two insect populations was also analyzed.
    Population growth, distribution pattern and sampling technique of Thrips palmi on eggplant
    GU Xiuhui, BEI Yawei, GAO Chunxian, CHEN Huaping
    2000, (6):  866-868. 
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    Population growth of Thrips palmi Karny on eggplant (Solanum melongena L.) were analyzed by mathematical models.The rate of population increase (r) of the adults and immature (instars 1~2) T.palmi were estimated to be 0.0630 and 0.0801 respectively in the open fields, and 0.0983 and 0.1036 respectively in the greenhouse. K value of logistic curve of T.palmi was estimated to be 33.90 in the greenhouse, and 23.50 in the open fields. The relationship between mean crowding (M*) and mean density (M) of T.palmi per eggplant leaf were estimated by Iwao's M*-M regression.The regression equation of adult and immature T.palmi on eggplant were:M*=0.6011+1.468M and M*=7.2515+2.064M respectively. The regression equation of the number of adult and immature was M*=7.5138+1.9119M.When the population density of the adults and immature T.palmi per eggplant leaf were 10 to 100, the number of sampling should be 78 to 44.
    Effects of temperature,relative humidity and pH on germination of chalkbrood fungus,Ascosphaera apis spore
    LIANG Qin, CHEN Dafu, WANG Jianding
    2000, (6):  869-872. 
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    Studies on the effects of environmental temperature,relative humidity and pH value on the germination of Ascosphaera apis spore at the stages of activation,enlargement and germ tube production showed that the germination was found to be independent of temperature within the range of 15~40℃ was and 25~40℃,respectively at the stage of activation and enlargement,but closely correlated with the temperature within the range of 25~37℃ at the stage of germ tube production,with the optimum range of 31~35℃.Relative humidity below 80% inhibited spore germination.pH value within the range of 5~7.8 did not affect the spore germination significantly,but pH<5 reduced the enlargement and germ tube production drastically.The results indicated that A.apis is a highly specialized pathogen for the life in honeybee larvae.
    Dynamics of respiration pathway in transgenic salt-tolerant wheat and its receptor under salt stress
    KONG Yingzhen, ZHOU Gongke, CUI Kairong, WANG Yafu, LI Hongyu
    2000, (6):  873-877. 
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    Using transgenic salt-tolerant wheat 89122 and its receptor Longchun 13 as test material, the dynamic changes of respiration pathway of wheat seedlings at different salt concentration were studied.The appearance of salt respiration was later in 89122 than in Longchun 13.The changes of Valt and ρValt of both varieties had different patterns during salt stress process.Valt was suppressed by high salt levels, but could be induced by low salt levels in Longchun 13. The ρValt and ρ'Vcyt of two varieties were cooperatively regulated with each other to adapt to salt stress,and ρ'Vcyt was the main electron transport pathway.The possible physiological roles of cyanide-resistant respiration were also discussed.It was suggested that the operation intensity of cyanide-resistant respiration could serve as a physiological index of plant salt-tolerance.
    Effect of osmotic stress on wheat membrane injury under different CO2 concentrations
    XU Yangcang, WANG Jin, LIN Jiusheng, WANG Genxuan
    2000, (6):  878-880. 
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    This paper studied the variation of active oxygen content and membrane permeability in leaves of spring wheat seedling exposed to osmotic stress under normal 350μl·L-1 and doubled CO2 concentration 700μl·L-1.The results indicate that the increasing rate of O2·- and H2O2,and the membrane permeability in wheat leaves exposed to osmotic stress in normal CO2 concentration were higher than those in doubled CO2.Accordingly,it is suggested that doubled CO2 can reduce the membrane oxidative injury caused by osmotic stress,and increase plant drought resistance.
    Effect of elevated CO2 concentration on photosynthesis and antioxidative enzyme activities of wheat plant grown under drought condition
    CHEN Xiong, WU Dongxiu, WANG Genxuan, RRN Hongxu
    2000, (6):  881-884. 
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    The photosynthesis and antioxidative enzyme activities of wheat plants grown in two open top chambers with CO2 concentrations of 350μmol·mol-1 and 700μmol·mol-1 were examined under drought stress.The result showed that elevated CO2 concentration obviously enhanced the photosynthesis,stomatal resistance and water use efficiency,but decreased the transpiration of wheat.Doubled CO2 concentration significantly increased the activities of CAT,POD and SOD,which enhanced the abilities of antioxidative defence and drought tolerance.
    Dynamic changes of respiration pathway and active oxygen levels in subcultured tobacco callus
    ZHOU Gongke, KONG Yingzhen, LI Hongyu, Wen Jiangqi, LIANG Houguo
    2000, (6):  885-888. 
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    During the growth and senescence of tobacco callus, the total respiration rate showed two peaks on the 11th and 19th day,respectively. The development and operation of alternative pathway increased gradually,reached the maximum between two respiration peaks,and then declined in the following days, but the cytochrome pathway was still as a main electron transport pathway consistently. Analysis on the levels of active oxygen species during the growth and senescence process in tobacco callus suggested that H2O2 and O2?- were involved in some way in the induction of the development and operation of the alternative pathway,but the increase of production rate of OH might suppress both the development and operation of the alternative pathway, which were enhanced by H2O2 and O2?- respectively. These results were further proved by the use of active oxygen scavengers. The possible participation of the alternative pathway enhanced by active oxygen in the initial senescence process was discussed.
    Effects of Ca2+,ABA and H3PO4 on relaxing stress of Na2CO3 and NaCl
    YAN Hong, SHI Decheng
    2000, (6):  889-892. 
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    Two groups of Aneurolepidium chinense seedlings were stressed by 300mmol稬-1 NaCl and 100mmol稬-1 Na2CO3,respectively and the effect of ABA,Ca2+ and H3PO4 on relaxing their stress was studied.The results show that external Ca2+,ABA and H3PO4 could obviously mitigat the inhibitory effect of NaCl and NaCO3 on seedling growth. In the treatment of Na2CO3,praying it on leaves had a better effect than root irrigating,while in the treatment of NaCl,there was no significant difference.The effect of Ca(NO3)2 was much better than that of CaCl2,and of mingling CaCl2 and ABA had a much better effect than CaCl2 or ABA alone.
    Nitrogen dynamics in different organs of Calamagrostis angustifolia and Carex lasiocarpa in Sanjiang plain
    SUN Xueli, LIU Jingshuang, CHU Yanru
    2000, (6):  893-897. 
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    The dynamics of nitrogen content and storage in different organs of Calamagrostis angustifolia and Carex lasiocarpa which are dominant vegetation in swamp wetland were determined,and the utilization rate of nitrogen and its nutrient limitation in the region were analyzed.The results showed that the aboveground and underground biomass might be described by p=γ+αtt2 and p=a0+b0t,respectively.The content of total N,NH4+-N and NO3--N varied widely with different organs because of the effects of soil water,nutrient content, atmospheric temperature,vegetable feature and selective absorption to nitrogen,etc.The content of NO3--N in different organs varied less than that of NH4+-N,and NH4+-N/NO3--N was <1.The N:P content less than 14 in two vegetations showed that it was N but not P was the limitation nutrient to the growth of vegetation in this region,moreover,the limitation was less in July than in August.This conclusion was also drawn from the analysis of the NH4+-N and NO3--N content in soil.
    Nitrogen content variation in litters of Deyeuxia angustifolia and Carex lasiocarpa in Sanjing plain
    LIU Jingshuang, SUN Xueli, YU Junbao
    2000, (6):  898-902. 
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    This paper dealt with the litter of two dominant species Deyeuxia angustifolia and Carex lasiocarpa in swamp of Sanjiang Plain,and analyzed the seasonal variation and content feature of nitrogen in litter and its roles on maintaining matter equilibrium in ecosystems.The nitrogen content in litter decreased with the increasing temperature and aboveground biomass.The weightlessness rate of litter increased with time,and the annual accumulative weightlessness rates of D.angustifolia and C.lasiocarpa were 32.2% and 27.7%,respectively.The annual accumulative nitrogen input amount of D.angustifolia community was 1478mg穖-2, C.lasiocarpa 587mg穖-2,while the annual accumulative nitrogen output amount in litter of D.angustifolia community was 759mg穖-2, C.lasiocarpa 410mg穖-2.It was suggested that the nitrogen input amount was higher than output,and that the state of nitrogen accumulation was beneficial to the stability of the ecosystems.
    Element concentrations in Rheum palmatum and R.likiangense plants and soil in Tibet plateau
    XIE Zongqiang
    2000, (6):  903-906. 
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    The characteristics of element concentrations in Rheum palmatum and R.likiangense plants and soil were studied using ICP method.The results showed that the P concentrations in soil was significantly lower than that in leaves and rhizomes;Fe concentration was 50~100 times higher in soil than in rhizomes,and leaves, and without significant difference between rhizomes and leaves;Na,Mn and Cu concentrations appeared soil>leaves>rhizomes;and Ca concentration showed soil <leaves <rhizomes for R.palmatum,and soil>leaves>rhizomes for R.likiangense. Although K, Mg, Ca, Mn and Zn concentrations were obviously different between soils of the 2 species, K and Mg concentrations were consistent in their leaves or rhizomes,and the difference of Ca, Mn and Zn concentrations between their rhizomes was insignificant.
    Ecological study on relationship between desertification process and vegetation dynamics in west of northeast China:Vegetation classification
    GUAN Wenbin, ZENG Dehui, JIANG Fengqi
    2000, (6):  907-911. 
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    Based on the data obtained from 72 plant community plots and 276 plant species in Hulunbeier Sandy Land and Kerqin Sandy Land in the northeast desertification region of China,TWINSPAN analysis was carried out. Meanwhile the practical classification result was obtained by Detrended correspondence Analysis (DCA). Under the vegetation classification principles of China, the vegetation classification system of the desertification regions in northeast China was preliminarily established,which includes 6 vegetation types,11 subtypes,40 formations,and 55 associations.
    Comparison analysis between potential and actual pattern of artificial oases in arid region
    JIA Baoquan, CI Longjun, YANG Xiaohui, YANG Jiequan, PAN Borong
    2000, (6):  912-916. 
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    Based on theoretical analysis and demonstration research, the conception of potential pattern in the agriculture landscape of artificial oases in Xinjiang arid region and its analysis unit were discussed. The potential landscape pattern was defined as the one composed by spatial units with basic characteristics and properties which had no change or less change with the time.In agriculture landscape,soil was found to be a relatively stable element,and hence,different soil classification unit could be used to analyze the potential landscape pattern. A case study was carried out to analyze the potential and actual pattern of the artificial oases in Shihezi reclamation area by using the indexes of diversity, evenness, aggregation, mean patch elongation, patch shape fragmentation and mean patch fractal dimension. The result showed that the landscape pattern changed orderly from the potential to actual pattern, and the potential pattern could be used as the absolute criterion for researches on pattern changes in agriculture landscape.
    Optimal models on sustainable management of oases ecosystem in southern margin of Taklamakan Desert
    LI Xiaoming, ZHANG Ximing, WANG Yuan, WU Yankui
    2000, (6):  917-922. 
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    On the basis of analyzing the distribution feature of water resource and the canal water utilization coefficient of oases in southern margin of Taklamakan Desert,observing the wind prevention efficiency of shelterbelt through a simulation experiment in wind tunnel,and 15 years researching the comprehensive control of desertified land in Cele Oasis,a series of optimal models on sustainable management of oases ecosystem is southern margin of Taklamakan Desert were proposed i.e.,the optimal model on “moderated osais”,the optimal model on structure of wind breaks, the optimal model on comprehensive control of desertified land,and the optimal model on planting structure of corps.
    Impact of precipitation and underground water level in the edge of oases on growth and decline of Nitraria tangugtorum community
    YANG Zihui, GAO Zhihai
    2000, (6):  927-930. 
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    Based on the data from underground water monitoring,meteorological measuring and fixed sample square investigating in successive years at the edge of the oasis in Minqin,Gansu,the impact of precipitation and underground water on the growth and decline of Nitraria tangutorum community was studied.The result showed that the desiccated environment in oases driven by the decline of underground water level was favorable for the growth and develoment of N.tangutorum community,and made this species more xerophilous.This declining underground water level was not a limiting factor for N.tangutorum growth in late years.These N.tangutorum-dominated communities were predicted to survive comparatively longer,and to function as sand fixer and wind breaker at oasis edge in Minqin.When average annual precipitation was about 110mm, N.tangutorum would maintain its normal growth,but the community couldn't spread freely.Only when the annual precipitation was up 140mm in two years running,could its growth be improved.
    Design and implementation of a landscape analysis system based on remote sensing data
    YUAN Yinhuan, QIN Qiming, LU Rongjiang
    2000, (6):  927-930. 
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    Because of the functions of Geographic Information System(GIS) being not satisfied to the requirements of landscape analysis,a landscape analysis system was designed with Visual C++ and demonstrated with remote sensing data.This system adopted the method f picking up patch boundary pixel set,improved the patch searching speed,and supplied some landscape analysis functions,such as the calculation of the distance between patches,and the boundary length of neighboring patch,which are not provided by current GIS.It was used to analyzed the landscape of suburbs in northwest Beijing,and the shortcomings of current GIS applied in landscape analysis were overcome.
    Effect of Cadmium on soil animal community structure
    LI Zhongwu, WANG Zhenzhong, ZHANG Youmei, XIN Xiejia
    2000, (6):  931-934. 
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    A indoor simulating test showed that there existed a close relationship between the community structure of soil animal and the concentration of soil Cd. When the concentration of soil Cd was high (99.48mg穔g-1),the species,quantity,diversity index,homogeneous index,and abundance of soil animal were low.With the concentration going down,all indexes above increased gradually.When the concentration of soil Cd was 2.27mg穔g-1,all the indexes were the same as control.The species and individuals of soil animal were negatively related with the natural logarithm of Cd concentration in soil.
    Correlation of photoplankton and its environmental factors in Rushan bay
    CUI Yi, CHEN Bijuan, MA Shaosai
    2000, (6):  935-938. 
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    The relationship between photoplankton and its environmental factors in Rushan Bay was studied from June to September,1995.The result shows that there existed a negative correlation between the number of photoplankton and the content of inorganic nutrients.The correlation coefficients for inorganic nitrogen and phosphorus were -0.67 and -0.80,respectively.The dissolved oxygen and chlorophyll-a were positively correlated to photoplankton,and their correlation coefficients were 0.92 and 0.85 respectively.Based on N/P analysis,the content of inorganic nitrogen was relatively short to the reproductive growth of photoplankton during experimental months,except for the last ten days of August.
    Environmental characteristic of walleye pollock fishing ground in high seas of the Okhotsk Sea in summer
    CHEN Jufa, TANG Qisheng
    2000, (6):  939-942. 
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    Based on the acoustic survey on the resource of walleye pollock (Theragra chalcogramma) in the high seas of the Okhotsk Sea,the distribution of walleye pollock and the environmental characteristics of its fishing ground were studied,and the relationship between them were analyzed.In August,the high schooling area of walleye pollock was situated in the waters with a depth of less than 500 meters and to the north of 55°N.Walleye pollock mainly distributed in 150~300m depth,and lived in groups.The main food was Euphausia pacifica,and the densely populated area of walleye pollock was roughly consistent with that of Euphausia pacifica.The thermocline was observed at 0~50m depth,the temperature changed at a rate of 0.25℃ per meter,and the cold water mass was roughly located in 50~150m layer.The fish was mainly distributed in the layer below the cold water mass,because of the impeding effect of thermocline and the limiting action of fish food.It seldom inhabited the water below 400m depth,partly because the dissolved oxygen there was rather low.
    Advance in studies on compensatory growth of aquatic animals after starvation or undernutrition
    WU Lixin, DONG Shuanglin
    2000, (6):  943-946. 
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    This paper reviewed the studies on the compensatory growth of aquatic animals after starvation or undernourisment.The extent of compensatory growth,its affecting factors,physiological mechanisms,changes in chemical composition and dynamics of growth rate were discussed.The experimental design problems and the application prospects of related studied were also analyzed.
    Protein secretion from drug-resistant bacteriaa suitable target for new antibiotics
    GUAN Jiafa, FAN Chengying, LIAO Lianhua
    2000, (6):  947-950. 
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    This paper reviewed the pathways of bacterial protein secretion and discussed the targets of pathogenic bacteria for antibiotics.Inhibition of protein secretion could lead to the growth decline,morphological alteration,and reduction of bacterial virulence,as well as the deprivation of their drug resistant.It was concluded that protein secretion could be a suitable target for new antibiotic agents.
    Factors affecting colonization of introduced microorganisms on plant roots
    ZHANG Bingxin, ZHANG Ping, CHEN Xiaobin
    2000, (6):  951-953. 
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    Microorganisms such as biological control agents (BCA), plant growth promoting rhizobacteria (PGPR) and yield increasing bacteria (YIB) were introduced along growing roots.The colonization process of introduced bacteria was proved that they attached root tipfirst,then distributed along roots,multiplicated there,and survived as certain population size.The colonization location was closely related with root exudates,which was usually at the junction between cortex cells or at the base of lateral roots or root hairs. The variation of colonization by introduced microorganisms in the rhizosphere was caused by biotic and abiotic factors. Biotic factors included the physiological characters of introduced microorganisms and interactions between introduced microorganisms and native microbes. The more important factors were plant genotypes which associated with introduced beneficial microbes and regulated the population and community of those microbes affecting the colonization of introduced microorganisms. Abiotic factors here referred to soil environmental conditions,e.g.,soil texture, water content,soil temperature and pH value.
    Ecotourism exploitation model in Bita Lake Natural Reserve of Yunnan
    YANG Guihua, WANG Yuehua, ZHONG Linsheng
    2000, (6):  954-956. 
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    Bita lake provincial natural reserve is located in Shangri-La region of North-western Yunnan,and was set as a demonstrating area for ecotourism exploitation in 1998.After a year's exploitation construction and half a year's operation as a branch of the 99' Kunming International Horticulture Exposition to accept tourists,it was proved that the ecotourism demonstrating area attained four integrated functions of ecotourism,i.e,tourism,protection,poverty clearing and environment education.Five exploitation and management models including function zoned exploitation model, featured tourism communication model signs system designing model,local Tibetan family reception model and environmental monitoring model,were also successful,which were demonstrated and spreaded to the whole province.Bita lake provincial natural reserve could be a good sample for the ecotourism exploitation natural reserves of the whole country.
    Effect of combined treatment of 60Coy-ray and EMS on antioxidase activity and ODAP content in Lathyrus sativus
    QIN Xincheng, WANG Fei, WANG Xiaojuan, ZHOU Gongke, LI Zhixiao
    2000, (6):  957-958. 
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    Lathyrus sativus seeds were treated with 60Coγ-ray and EMS(ethyl methane sulfonate), and their emergence rate and SOD,POD and CAT activities were determined. The result indicated that the treatment decreased the emergence rate. The activities of SOD and POD were changed in accordance with the increase of irradiation dose and EMS concentration, while that of CAT had no obvious change. After treatment, the ODAP content in Lathyrus sativus decreased. Amutant was developed, with toxin content of 0.1%, compared to 0.2% in control.
    Effect of Nerium indicum on killing Oncomelania hupensis
    YANG Yi, KE Wenshan, WANG Wanxian, MA Anning, CHEN Quansheng
    2000, (6):  959-960. 
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    A laboratory experiment at 20±5℃ shows that the water extract of fresh Nerium indicum had an obvious effect on killing Oncomelania hupensis. Treated with 0.1% water extract for four days, the mortality of O. hupensis was up to 100%. The effect of different tissues of N. indicum on O. hupensis was in order of stem phloem>leaf>root phloem>flower. The effect of N. indicum on O. hupensis was about ten times higher than that of Pterocarya stenoptera and Rumex japonicus, and was equal to that of 1×10-3mg·L-1 niclosamidum.
    Articles
    Relationship between light and regeneration character of Huangshan pine
    FU Songling, HUANG Chengling, CAO Hengsheng, WU Zemin
    2000, (6):  801-804. 
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    The growth and physiological characters of 1~3 years old Huangshan pine seedlings in pure and mixture plots with four different transparancy were determined,and the germination percentage of seeds and their complex stressing vigour were tested.Meanwhile,the regeneration mechanism of Huangshan pine in natural forest was studied in this paper.The results showed that the plumpness of seeds was 65%,the germination percentage was 27%,and the complex stressing vigour was 26%.The lower germination percentage affected the reproduction of Huangshan pine.The photosynthetic rate was more affected by solar energy,but less by humidity and surface temperature.With high light composation,Huangshan pine's regeneration under forest was difficult.The seedlings of Huangshan pine in mixed coniferous and broadleave tree plots were at a disadvantage because of slow growth and insufficient ligth.
    Impacts of forest and precipitation on runoff and sediment in Tianshui watershed and GM models
    OUYANG Hui
    2000, (6):  805-808. 
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    This paper analyzed the impacts of foret stand volume and precipitation on annual erosion modulus,mean sediment,maximum sediment,mean runoff,maximum runoff,minimum runoff,mean water level,maximum water level and minimum water level in Tianshui watershed,and also analyzed the effect of the variation of forest stand volume on monthly mean runoff,minimum runoff and mean water level.The dynamic models of grey system GM(1,N) were constructed to simulate the changes of these hydrological elements.The dynamic GM models on the impact of stand volumes of different forest types(Chinese fir,masson pine and broad leaved forests)with different age classes(young,middle aged,mature and over mature)and that of precipitation on the hydrological elements were also constructed,and their changes with time were analyzed.
    Articles
    Occurrence and control of frost in Tilia amurensis and Fraxinus mandshurica young plantations
    CHEN Xiangwei, ZHANG Yu, MA Hongbo
    2000, (6):  809-813. 
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    The changes of minimum temperature periodical biological phenomena and frost in yound Tilia amurensis and Fraxinus mandshurica plantation stands were systematically analyzed based on the vertical gradient observation and plot investigation.Meanwhile,the resistance of Tilia amurensis to late frost was also studied.The results showed that the phenophase of T.amurensis was later than that of F.mandshurica.Influenced by significant temperature inversions in this area,the phenophase of T.amurensis and F.mandshurica changed regularly in different aspects and slope positions.The sprouts on west slope started earlier than that on east slope.The higher they grew on the slope,the earlier they sprouted,with the earliest sprout at the top of slope.Late frost in this area only took place when the trees were sprouting, but air temperature decreased significantly at the same time.The degree of injury from the late frost could be controlled effectively by selecting suitable site.Sites down the slope,especially the east slope,were not suitable for T.amurensis and F.mandshurica plantation in this research area.Chemical treatment and biological shading could prevent late frost injury through putting off sprout.Mixed plantations could prevent F.mandshurica and T.anurensis from late frost injury significantly,and the frost injury index and the proportion of the tree number of different injury grades were lower than those in pure stands.
    Optimized models of logging-tending system in cutting areas
    GUO Jiangang, JING Yun, ZHANG Ruohong, XIONG Wenyu, SU Jinyun
    2000, (6):  814-818. 
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    The comprehensive advantages of different logging tending systems in Pinus massoniana forest cutting area were evaluated by set pair analysis,based on the comparison of their economic and ecological benefits.The results showed that the optimized model for P.massoniana forests in Northern Fujian comprised 40% selective cutting,manual skidding,clear cutting in ribbon,and natural regeneration with artificial aids,which could also be used in the nearby forests with conditions similar to the experimental area.
    Ecosystem management of settlement area in Xingshan County
    GUO Zhongwei, Li Dianmo
    2000, (6):  819-826. 
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    In the immigrant settlement area of Three-Gorges reservoir region in Xingshan County, Hubei Province,the ecological problems were the restoration of degraded ecosystem, rehabilitation of degraded crop land, and reconstruction of towns and villages. The key to the construction of the settlement area was reassigning the way of land use. The major aim of restoration of natural ecosystems should be to improve water conservation capacity of the land,because this area is located in the catchment of the Xiangxi River. The goals of management were determined as the coordinated development of both agricultural and natural forest ecosystems,the maintenance and increase of water conservation capacity of ecosystems,and the maintenance and extension of wildlife habitats.For the purpose of effective ecosystem management, the area was classified into four divisions of functional conservation region, functional rehabilitation, natural reserves and natural maintenance. The ecosystem management of the settlement area in Xingshan County was implemented in every land cell,using GIS and the typical grid-square survey method.The approach of multi-objects optimal spatial plan was developed in this paper,in which,special emphasis was put on the ecological, economic and social benefits in the construction of towns and villages. According to the scheme of management,the cover of forest in the settlement area,would increase by 30.19%, and water conservation capacity of the ecosystems would raise by 38.7%.
    Systematic analysis of agro-ecoclimatic resources in Gansu Province
    BAI Yongping
    2000, (6):  827-832. 
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    Based on the over years data from 86 meteorological stations in Gansu Province,the agro-ecoclimatic resources in this province was systematically analyzed.Resource indices Cr,efficiency indices Ce and utilization coefficient K were calculated by using the dynamic models of agro-ecoclimatic suitability degree.According to the average monthly efficiency indices Ce,the agro-ecoclimatic resources were divided into 7 types and 3 subtypes by fuzzy cluster.The potentiality matching condition and utility degree of agro-ecoclimatic resources showed the evident characteristic of spatial differentiation.Generally,the south was superior to the north,and the east was superior to the west in terms of these parameters,with the type of South Gansu Mountain much better than that of Hexi Corridor.Some suggestions about the exploitation and utilization of the agro-ecoclimatic resources in Gansu province were proposed.
    Cluster analysis methods appropriate for classification of drought-resistant wheat ecotypes
    CHAI Shouxi
    2000, (6):  833-838. 
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    The appropriate cluster analysis methods for classification of drought-resistant wheat ecotypes were investigated,based on the analysis of 21 morphologic and agronomic characters of 15 winter wheat cultivars. According to the proximity degree to the results from experts experiences,the cluster results using original data were orderly better than those using Varimax orthogonal rotation, Promax skew intersection rotation,and principal component analysis with phenotypic mean's correlation matrix. The results using Euclidean distance were greater than those using Mahalanobis distance.The clustering methods of correspondent analysis and fuzzy cluster were better than those of nearest distance, furthest distance or group average method (UPGMA).Among all cluster results from various methods combined,the two cluster results from the fuzzy cluster using original data and from the correspondence analysis method were closest to the results of experts' experience.Based on both comparisons of results and examination of the performance of different strategies with several statistical properties, the two methods mentioned above were also acceptable.
    A wintering habitat model for red crown crane
    LI Wenjun, WANG Zijian
    2000, (6):  839-842. 
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    A mathematical model was established based on GIS and RS to simulate and predict the habitat distribution of red crown crane(Grus japonensis) in Yancheng Biosphere Reserve,Jiangsu Province,China.The model was tested through calculating the match coefficience of observed and predicted presence/absence data,which was 72.63%,showing that the model could be used to reflect the habitat distribution of red crown crane.
    A method for designing buffer zone in Yancheng Biosphere Reserve:taking red crown crane as objective species
    LI Wenjun, WANG Zijian
    2000, (6):  843-847. 
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    Social,economic,ecological and geomorphic factors are needed to be considered when designing the buffer zone of natural reserve.In this paper,the Analytic Hierarchy Process(AHP) was applied to design the width of buffer zone.Under considerating the influences in different sections around the reserve,different widths of the buffer zone were designed,and a case study was carried out in Yancheng Biosphere Reserve.The results showed that the proposed method was reasonable and practicable in designing the buffer zone of nature reserve.
    Impact of starvation on predation by male adult Chrysopa septempunctata
    ZOU Yunding, LI Guiting, ZHOU Xiazhi, LIU Tongwen
    2000, (6):  848-850. 
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    The predation on Schizaphis graminum by male adult Chrysopa septempunctatata at various levels of starvation was examined in this paper.Th results showed that the functional reactive types of predator were not altered by its starvation duration,and the amount(Na) of catched S.graminum by C.septempunctata wihin 24hrs varied with duration time(t),which could be expressed by the model: Na=100/(1+e-0.3088-0.0996t).The relationship between predation rate(v) and time(x) could be described as v=6.7117x-0.7928.The male adult predators preferred feeding on the young preys.
    Impact of high temperature on testicular growth and development of valuable silkworm Antheraea yamamai(Lepidoptera:Saturiidae)
    YE Gongyin, HU Cui, GONG He
    2000, (6):  851-855. 
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    The results indicated that high temperature had a significant impact on the growth and development of testis in Japanese oak silkworm Antheraea yamamai.The testicular size of the 3rd and 4th instar larvae increased within the range from 20 to 29℃,and slightly decreased at 32℃.While in the 5th instar,it decreased within the range from 20 to 26℃,with the biggest size at 20℃.The testis was almost hard to grow and develop because the larvae could not survive at 29 to 32℃.When the mature larvae were treated at 32℃ at the beginning of coconing or at the 1st or 6th day of pupating,the growth of testicular size and spermatogenesis were significantly arrested,and the sperm number and the content of soluble protein in the testis markedly decreased.When the male moth of the 1st day was treated at 32℃,the activity of the sperms in the testis obviously decreased,in contrast to the treatment at 20℃.It is concluded that for the egg raising of the silkworm,its mature larvae,puape in cocoons and male moths should not be exposed to 32℃ from cocooning to adult stage.The proper temperature for rearing 3rd,4th and 5th instar larvae was discussed.
    Lifetable of cotton bollworm under different control condition
    YANG Yizhong, PANG Xionfei, LIANG Guangwen
    2000, (6):  856-860. 
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    The lifetables of 3rd and 4th generation of cotton bollworm Helicoverpa armigera Hubner were established by action factors under four different control conditions.The results showed that under natural control,the egg parasitic rates of 3rd and 4th cotton bollworm were 4.39% and 1.19%,the predatory rates were 21.11% and 15.80%,and the larvae parasitic rates were 19.34% and 16.20% respectively.The indexes of population trend were only 0.0032 and 0.0014 respectively,after using selective pesticides IKI and Bt to control cotton bollworm.Though the index of population trend decreased to 48.66% and 61.67% after contantly praying chemical pesticides,the number of predators also decreaseed to 23.48% and 41.26% respectively.Transgenic Bt cotton could inhibit the population increase of cotton bollworm,but had no effect on predators.The parasitic rates of 3rd and 4th cotton bollworm on Transgenic Bt cotton were 51.14% and 0% respectively,as compared to control.
    Articles
    Effect of rice variety resistance on population dynamics of Nilaparvata lugens and Sogatella furcifera
    WANG Rongfu, ZHANG Chenglin, ZOU Yunding, LÜ Liang, CHENG Xianian
    2000, (6):  861-865. 
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    The effect of rice varieties with different insect resistance on dynamics of Nilaparvata lugens and Sogatella furcifera population was examined,based on the investigation of their inhabiting ratio,egg amount, survival rate of egg and nymph,nymph development,and the amount of their offspring population.Four rice varieties,TN1,N22,AsD7 and Ptb 33 were investigated.Ptb 33 had a significantly lower inhabiting ratio, egg amount,and survival ratio of eggs and nymphs of both parasitic populations,a prolonged development time from nymphs to adults,and an inhibited offspring population, indicating an evident resistance of this host variety.N22 and AsD7 inhibited the development of offspring S. furcifera and N. lugens, respectively.The parasitic populations of S. furcifera and N. lugens developed more rapidly on TN 1,compared with N.lugens population on N22 and S. furcifera on AsD7. The relationship between the quantitative dynamics of both population and rice variety replacement was discussed,and the possibility of using resistant rice varieties to control these two insect populations was also analyzed.
    Population growth, distribution pattern and sampling technique of Thrips palmi on eggplant
    GU Xiuhui, BEI Yawei, GAO Chunxian, CHEN Huaping
    2000, (6):  866-868. 
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    Population growth of Thrips palmi Karny on eggplant (Solanum melongena L.) were analyzed by mathematical models.The rate of population increase (r) of the adults and immature (instars 1~2) T.palmi were estimated to be 0.0630 and 0.0801 respectively in the open fields, and 0.0983 and 0.1036 respectively in the greenhouse. K value of logistic curve of T.palmi was estimated to be 33.90 in the greenhouse, and 23.50 in the open fields. The relationship between mean crowding (M*) and mean density (M) of T.palmi per eggplant leaf were estimated by Iwao's M*-M regression.The regression equation of adult and immature T.palmi on eggplant were:M*=0.6011+1.468M and M*=7.2515+2.064M respectively. The regression equation of the number of adult and immature was M*=7.5138+1.9119M.When the population density of the adults and immature T.palmi per eggplant leaf were 10 to 100, the number of sampling should be 78 to 44.
    Effects of temperature,relative humidity and pH on germination of chalkbrood fungus,Ascosphaera apis spore
    LIANG Qin, CHEN Dafu, WANG Jianding
    2000, (6):  869-872. 
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    Studies on the effects of environmental temperature,relative humidity and pH value on the germination of Ascosphaera apis spore at the stages of activation,enlargement and germ tube production showed that the germination was found to be independent of temperature within the range of 15~40℃ was and 25~40℃,respectively at the stage of activation and enlargement,but closely correlated with the temperature within the range of 25~37℃ at the stage of germ tube production,with the optimum range of 31~35℃.Relative humidity below 80% inhibited spore germination.pH value within the range of 5~7.8 did not affect the spore germination significantly,but pH<5 reduced the enlargement and germ tube production drastically.The results indicated that A.apis is a highly specialized pathogen for the life in honeybee larvae.
    Dynamics of respiration pathway in transgenic salt-tolerant wheat and its receptor under salt stress
    KONG Yingzhen, ZHOU Gongke, CUI Kairong, WANG Yafu, LI Hongyu
    2000, (6):  873-877. 
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    Using transgenic salt-tolerant wheat 89122 and its receptor Longchun 13 as test material, the dynamic changes of respiration pathway of wheat seedlings at different salt concentration were studied.The appearance of salt respiration was later in 89122 than in Longchun 13.The changes of Valt and ρValt of both varieties had different patterns during salt stress process.Valt was suppressed by high salt levels, but could be induced by low salt levels in Longchun 13. The ρValt and ρ'Vcyt of two varieties were cooperatively regulated with each other to adapt to salt stress,and ρ'Vcyt was the main electron transport pathway.The possible physiological roles of cyanide-resistant respiration were also discussed.It was suggested that the operation intensity of cyanide-resistant respiration could serve as a physiological index of plant salt-tolerance.
    Effect of osmotic stress on wheat membrane injury under different CO2 concentrations
    XU Yangcang, WANG Jin, LIN Jiusheng, WANG Genxuan
    2000, (6):  878-880. 
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    This paper studied the variation of active oxygen content and membrane permeability in leaves of spring wheat seedling exposed to osmotic stress under normal 350μl·L-1 and doubled CO2 concentration 700μl·L-1.The results indicate that the increasing rate of O2·- and H2O2,and the membrane permeability in wheat leaves exposed to osmotic stress in normal CO2 concentration were higher than those in doubled CO2.Accordingly,it is suggested that doubled CO2 can reduce the membrane oxidative injury caused by osmotic stress,and increase plant drought resistance.
    Effect of elevated CO2 concentration on photosynthesis and antioxidative enzyme activities of wheat plant grown under drought condition
    CHEN Xiong, WU Dongxiu, WANG Genxuan, RRN Hongxu
    2000, (6):  881-884. 
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    The photosynthesis and antioxidative enzyme activities of wheat plants grown in two open top chambers with CO2 concentrations of 350μmol·mol-1 and 700μmol·mol-1 were examined under drought stress.The result showed that elevated CO2 concentration obviously enhanced the photosynthesis,stomatal resistance and water use efficiency,but decreased the transpiration of wheat.Doubled CO2 concentration significantly increased the activities of CAT,POD and SOD,which enhanced the abilities of antioxidative defence and drought tolerance.
    Dynamic changes of respiration pathway and active oxygen levels in subcultured tobacco callus
    ZHOU Gongke, KONG Yingzhen, LI Hongyu, Wen Jiangqi, LIANG Houguo
    2000, (6):  885-888. 
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    During the growth and senescence of tobacco callus, the total respiration rate showed two peaks on the 11th and 19th day,respectively. The development and operation of alternative pathway increased gradually,reached the maximum between two respiration peaks,and then declined in the following days, but the cytochrome pathway was still as a main electron transport pathway consistently. Analysis on the levels of active oxygen species during the growth and senescence process in tobacco callus suggested that H2O2 and O2?- were involved in some way in the induction of the development and operation of the alternative pathway,but the increase of production rate of OH might suppress both the development and operation of the alternative pathway, which were enhanced by H2O2 and O2?- respectively. These results were further proved by the use of active oxygen scavengers. The possible participation of the alternative pathway enhanced by active oxygen in the initial senescence process was discussed.
    Effects of Ca2+,ABA and H3PO4 on relaxing stress of Na2CO3 and NaCl
    YAN Hong, SHI Decheng
    2000, (6):  889-892. 
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    Two groups of Aneurolepidium chinense seedlings were stressed by 300mmol稬-1 NaCl and 100mmol稬-1 Na2CO3,respectively and the effect of ABA,Ca2+ and H3PO4 on relaxing their stress was studied.The results show that external Ca2+,ABA and H3PO4 could obviously mitigat the inhibitory effect of NaCl and NaCO3 on seedling growth. In the treatment of Na2CO3,praying it on leaves had a better effect than root irrigating,while in the treatment of NaCl,there was no significant difference.The effect of Ca(NO3)2 was much better than that of CaCl2,and of mingling CaCl2 and ABA had a much better effect than CaCl2 or ABA alone.
    Nitrogen dynamics in different organs of Calamagrostis angustifolia and Carex lasiocarpa in Sanjiang plain
    SUN Xueli, LIU Jingshuang, CHU Yanru
    2000, (6):  893-897. 
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    The dynamics of nitrogen content and storage in different organs of Calamagrostis angustifolia and Carex lasiocarpa which are dominant vegetation in swamp wetland were determined,and the utilization rate of nitrogen and its nutrient limitation in the region were analyzed.The results showed that the aboveground and underground biomass might be described by p=γ+αtt2 and p=a0+b0t,respectively.The content of total N,NH4+-N and NO3--N varied widely with different organs because of the effects of soil water,nutrient content, atmospheric temperature,vegetable feature and selective absorption to nitrogen,etc.The content of NO3--N in different organs varied less than that of NH4+-N,and NH4+-N/NO3--N was <1.The N:P content less than 14 in two vegetations showed that it was N but not P was the limitation nutrient to the growth of vegetation in this region,moreover,the limitation was less in July than in August.This conclusion was also drawn from the analysis of the NH4+-N and NO3--N content in soil.
    Nitrogen content variation in litters of Deyeuxia angustifolia and Carex lasiocarpa in Sanjing plain
    LIU Jingshuang, SUN Xueli, YU Junbao
    2000, (6):  898-902. 
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    This paper dealt with the litter of two dominant species Deyeuxia angustifolia and Carex lasiocarpa in swamp of Sanjiang Plain,and analyzed the seasonal variation and content feature of nitrogen in litter and its roles on maintaining matter equilibrium in ecosystems.The nitrogen content in litter decreased with the increasing temperature and aboveground biomass.The weightlessness rate of litter increased with time,and the annual accumulative weightlessness rates of D.angustifolia and C.lasiocarpa were 32.2% and 27.7%,respectively.The annual accumulative nitrogen input amount of D.angustifolia community was 1478mg穖-2, C.lasiocarpa 587mg穖-2,while the annual accumulative nitrogen output amount in litter of D.angustifolia community was 759mg穖-2, C.lasiocarpa 410mg穖-2.It was suggested that the nitrogen input amount was higher than output,and that the state of nitrogen accumulation was beneficial to the stability of the ecosystems.
    Element concentrations in Rheum palmatum and R.likiangense plants and soil in Tibet plateau
    XIE Zongqiang
    2000, (6):  903-906. 
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    The characteristics of element concentrations in Rheum palmatum and R.likiangense plants and soil were studied using ICP method.The results showed that the P concentrations in soil was significantly lower than that in leaves and rhizomes;Fe concentration was 50~100 times higher in soil than in rhizomes,and leaves, and without significant difference between rhizomes and leaves;Na,Mn and Cu concentrations appeared soil>leaves>rhizomes;and Ca concentration showed soil <leaves <rhizomes for R.palmatum,and soil>leaves>rhizomes for R.likiangense. Although K, Mg, Ca, Mn and Zn concentrations were obviously different between soils of the 2 species, K and Mg concentrations were consistent in their leaves or rhizomes,and the difference of Ca, Mn and Zn concentrations between their rhizomes was insignificant.
    Ecological study on relationship between desertification process and vegetation dynamics in west of northeast China:Vegetation classification
    GUAN Wenbin, ZENG Dehui, JIANG Fengqi
    2000, (6):  907-911. 
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    Based on the data obtained from 72 plant community plots and 276 plant species in Hulunbeier Sandy Land and Kerqin Sandy Land in the northeast desertification region of China,TWINSPAN analysis was carried out. Meanwhile the practical classification result was obtained by Detrended correspondence Analysis (DCA). Under the vegetation classification principles of China, the vegetation classification system of the desertification regions in northeast China was preliminarily established,which includes 6 vegetation types,11 subtypes,40 formations,and 55 associations.
    Comparison analysis between potential and actual pattern of artificial oases in arid region
    JIA Baoquan, CI Longjun, YANG Xiaohui, YANG Jiequan, PAN Borong
    2000, (6):  912-916. 
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    Based on theoretical analysis and demonstration research, the conception of potential pattern in the agriculture landscape of artificial oases in Xinjiang arid region and its analysis unit were discussed. The potential landscape pattern was defined as the one composed by spatial units with basic characteristics and properties which had no change or less change with the time.In agriculture landscape,soil was found to be a relatively stable element,and hence,different soil classification unit could be used to analyze the potential landscape pattern. A case study was carried out to analyze the potential and actual pattern of the artificial oases in Shihezi reclamation area by using the indexes of diversity, evenness, aggregation, mean patch elongation, patch shape fragmentation and mean patch fractal dimension. The result showed that the landscape pattern changed orderly from the potential to actual pattern, and the potential pattern could be used as the absolute criterion for researches on pattern changes in agriculture landscape.
    Optimal models on sustainable management of oases ecosystem in southern margin of Taklamakan Desert
    LI Xiaoming, ZHANG Ximing, WANG Yuan, WU Yankui
    2000, (6):  917-922. 
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    On the basis of analyzing the distribution feature of water resource and the canal water utilization coefficient of oases in southern margin of Taklamakan Desert,observing the wind prevention efficiency of shelterbelt through a simulation experiment in wind tunnel,and 15 years researching the comprehensive control of desertified land in Cele Oasis,a series of optimal models on sustainable management of oases ecosystem is southern margin of Taklamakan Desert were proposed i.e.,the optimal model on “moderated osais”,the optimal model on structure of wind breaks, the optimal model on comprehensive control of desertified land,and the optimal model on planting structure of corps.
    Impact of precipitation and underground water level in the edge of oases on growth and decline of Nitraria tangugtorum community
    YANG Zihui, GAO Zhihai
    2000, (6):  927-930. 
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    Based on the data from underground water monitoring,meteorological measuring and fixed sample square investigating in successive years at the edge of the oasis in Minqin,Gansu,the impact of precipitation and underground water on the growth and decline of Nitraria tangutorum community was studied.The result showed that the desiccated environment in oases driven by the decline of underground water level was favorable for the growth and develoment of N.tangutorum community,and made this species more xerophilous.This declining underground water level was not a limiting factor for N.tangutorum growth in late years.These N.tangutorum-dominated communities were predicted to survive comparatively longer,and to function as sand fixer and wind breaker at oasis edge in Minqin.When average annual precipitation was about 110mm, N.tangutorum would maintain its normal growth,but the community couldn't spread freely.Only when the annual precipitation was up 140mm in two years running,could its growth be improved.
    Design and implementation of a landscape analysis system based on remote sensing data
    YUAN Yinhuan, QIN Qiming, LU Rongjiang
    2000, (6):  927-930. 
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    Because of the functions of Geographic Information System(GIS) being not satisfied to the requirements of landscape analysis,a landscape analysis system was designed with Visual C++ and demonstrated with remote sensing data.This system adopted the method f picking up patch boundary pixel set,improved the patch searching speed,and supplied some landscape analysis functions,such as the calculation of the distance between patches,and the boundary length of neighboring patch,which are not provided by current GIS.It was used to analyzed the landscape of suburbs in northwest Beijing,and the shortcomings of current GIS applied in landscape analysis were overcome.
    Effect of Cadmium on soil animal community structure
    LI Zhongwu, WANG Zhenzhong, ZHANG Youmei, XIN Xiejia
    2000, (6):  931-934. 
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    A indoor simulating test showed that there existed a close relationship between the community structure of soil animal and the concentration of soil Cd. When the concentration of soil Cd was high (99.48mg穔g-1),the species,quantity,diversity index,homogeneous index,and abundance of soil animal were low.With the concentration going down,all indexes above increased gradually.When the concentration of soil Cd was 2.27mg穔g-1,all the indexes were the same as control.The species and individuals of soil animal were negatively related with the natural logarithm of Cd concentration in soil.
    Correlation of photoplankton and its environmental factors in Rushan bay
    CUI Yi, CHEN Bijuan, MA Shaosai
    2000, (6):  935-938. 
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    The relationship between photoplankton and its environmental factors in Rushan Bay was studied from June to September,1995.The result shows that there existed a negative correlation between the number of photoplankton and the content of inorganic nutrients.The correlation coefficients for inorganic nitrogen and phosphorus were -0.67 and -0.80,respectively.The dissolved oxygen and chlorophyll-a were positively correlated to photoplankton,and their correlation coefficients were 0.92 and 0.85 respectively.Based on N/P analysis,the content of inorganic nitrogen was relatively short to the reproductive growth of photoplankton during experimental months,except for the last ten days of August.
    Environmental characteristic of walleye pollock fishing ground in high seas of the Okhotsk Sea in summer
    CHEN Jufa, TANG Qisheng
    2000, (6):  939-942. 
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    Based on the acoustic survey on the resource of walleye pollock (Theragra chalcogramma) in the high seas of the Okhotsk Sea,the distribution of walleye pollock and the environmental characteristics of its fishing ground were studied,and the relationship between them were analyzed.In August,the high schooling area of walleye pollock was situated in the waters with a depth of less than 500 meters and to the north of 55°N.Walleye pollock mainly distributed in 150~300m depth,and lived in groups.The main food was Euphausia pacifica,and the densely populated area of walleye pollock was roughly consistent with that of Euphausia pacifica.The thermocline was observed at 0~50m depth,the temperature changed at a rate of 0.25℃ per meter,and the cold water mass was roughly located in 50~150m layer.The fish was mainly distributed in the layer below the cold water mass,because of the impeding effect of thermocline and the limiting action of fish food.It seldom inhabited the water below 400m depth,partly because the dissolved oxygen there was rather low.
    Advance in studies on compensatory growth of aquatic animals after starvation or undernutrition
    WU Lixin, DONG Shuanglin
    2000, (6):  943-946. 
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    This paper reviewed the studies on the compensatory growth of aquatic animals after starvation or undernourisment.The extent of compensatory growth,its affecting factors,physiological mechanisms,changes in chemical composition and dynamics of growth rate were discussed.The experimental design problems and the application prospects of related studied were also analyzed.
    Protein secretion from drug-resistant bacteriaa suitable target for new antibiotics
    GUAN Jiafa, FAN Chengying, LIAO Lianhua
    2000, (6):  947-950. 
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    This paper reviewed the pathways of bacterial protein secretion and discussed the targets of pathogenic bacteria for antibiotics.Inhibition of protein secretion could lead to the growth decline,morphological alteration,and reduction of bacterial virulence,as well as the deprivation of their drug resistant.It was concluded that protein secretion could be a suitable target for new antibiotic agents.
    Factors affecting colonization of introduced microorganisms on plant roots
    ZHANG Bingxin, ZHANG Ping, CHEN Xiaobin
    2000, (6):  951-953. 
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    Microorganisms such as biological control agents (BCA), plant growth promoting rhizobacteria (PGPR) and yield increasing bacteria (YIB) were introduced along growing roots.The colonization process of introduced bacteria was proved that they attached root tipfirst,then distributed along roots,multiplicated there,and survived as certain population size.The colonization location was closely related with root exudates,which was usually at the junction between cortex cells or at the base of lateral roots or root hairs. The variation of colonization by introduced microorganisms in the rhizosphere was caused by biotic and abiotic factors. Biotic factors included the physiological characters of introduced microorganisms and interactions between introduced microorganisms and native microbes. The more important factors were plant genotypes which associated with introduced beneficial microbes and regulated the population and community of those microbes affecting the colonization of introduced microorganisms. Abiotic factors here referred to soil environmental conditions,e.g.,soil texture, water content,soil temperature and pH value.
    Ecotourism exploitation model in Bita Lake Natural Reserve of Yunnan
    YANG Guihua, WANG Yuehua, ZHONG Linsheng
    2000, (6):  954-956. 
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    Bita lake provincial natural reserve is located in Shangri-La region of North-western Yunnan,and was set as a demonstrating area for ecotourism exploitation in 1998.After a year's exploitation construction and half a year's operation as a branch of the 99' Kunming International Horticulture Exposition to accept tourists,it was proved that the ecotourism demonstrating area attained four integrated functions of ecotourism,i.e,tourism,protection,poverty clearing and environment education.Five exploitation and management models including function zoned exploitation model, featured tourism communication model signs system designing model,local Tibetan family reception model and environmental monitoring model,were also successful,which were demonstrated and spreaded to the whole province.Bita lake provincial natural reserve could be a good sample for the ecotourism exploitation natural reserves of the whole country.
    Effect of combined treatment of 60Coy-ray and EMS on antioxidase activity and ODAP content in Lathyrus sativus
    QIN Xincheng, WANG Fei, WANG Xiaojuan, ZHOU Gongke, LI Zhixiao
    2000, (6):  957-958. 
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    Lathyrus sativus seeds were treated with 60Coγ-ray and EMS(ethyl methane sulfonate), and their emergence rate and SOD,POD and CAT activities were determined. The result indicated that the treatment decreased the emergence rate. The activities of SOD and POD were changed in accordance with the increase of irradiation dose and EMS concentration, while that of CAT had no obvious change. After treatment, the ODAP content in Lathyrus sativus decreased. Amutant was developed, with toxin content of 0.1%, compared to 0.2% in control.
    Effect of Nerium indicum on killing Oncomelania hupensis
    YANG Yi, KE Wenshan, WANG Wanxian, MA Anning, CHEN Quansheng
    2000, (6):  959-960. 
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    A laboratory experiment at 20±5℃ shows that the water extract of fresh Nerium indicum had an obvious effect on killing Oncomelania hupensis. Treated with 0.1% water extract for four days, the mortality of O. hupensis was up to 100%. The effect of different tissues of N. indicum on O. hupensis was in order of stem phloem>leaf>root phloem>flower. The effect of N. indicum on O. hupensis was about ten times higher than that of Pterocarya stenoptera and Rumex japonicus, and was equal to that of 1×10-3mg·L-1 niclosamidum.