Table of Content

15 March 2005, Volume 16 Issue 3

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Articles

Effects of artificial tending on Pinus tabulaeformis forest growth and its structural characteristics

CAO Yun^1,2,YANG Yie²,SONG Bingyu²,HUANG Heping², YANG Mingbo²,ZHENG Min²

2005, 16(03):  397-402 . 

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The investigation on the growth status,community composition,and structural characteristics of Pinus tabulaeformis forest artificially tended for six years showed that there were significant differences in the average DBH, height, and crown size of the forest among the treatments DA (trimming without intermediate cutting),FA (trimming and intermediate cutting) and CK (without trending).Treatment FA had the highest values of average DBH (7.8±0.29 cm),height (5.5±0.09 m) and crown size (249±7.24 cm),while the CK had the lowest ones.The average biomass of new leaf (1-year-old),old leaf (2 or more-year-old),and branch per tree increased significantly (P<0.01) with enhancing tending treatments.The aboveground biomass of treatment FA was the biggest (44.0 t·hm^-2),and that of CK was the smallest（14.9 t·hm^-2）.The leaf length and SLA at the early and terminal stages of development (May,June and September) had significant difference among the treatments, and the amount of community composition and the cover degree of undergrowth plants increased evidently under artificial tending treatments.

Niches of several mangrove species in Dongzhai Harbor of Hainan Island

LIAO Baowen¹,LI Mei¹,ZHENG Songfa¹,CHEN Yujun¹,ZHONG Cairong², HUANG Zhongqi²

2005, 16(03):  403-407 . 

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Employing the succession series of Kandelia candelAegiceras corniculatumcommunity in non-indigenous species Sonneratia apetala extension area as resource axes,and with three commonly used calculation formulae,this paper determined the niche breadth and overlap of mangrove populations. The results showed that the niche breadth decreased in order of Aegiceras corniculatum (3.8357) >Kandelia candel (3.3421) >Bruguiera gymnorrhiza (3.3180) >Avicennia marina (3.0975) >Sonneratia apetala (2.9137) >Sonneratia caseolaris (2.5724) > Ceriops tagal (1.8523) > Rhizophora stylosa (1.6897) > Bruguiera sexangula (1.0000),which could indicate the ecological adaptability and distribution range of the species.The niche overlap among K.candel,A.corniculatum,B.gymnorrhizaand A.marina was the largest,suggesting the intense competition among them,followed by the niche overlap of S.apetalawith S.caseolaris,A.corniculatum,K.candel and A.marina,S.apetala with R.stylosa and B.sexangula,S.apetala withC.tagal,and S.apetala with B.sexangula.

Effects of simulated water stress on photosynthesis rate and WUE of Fraxinus mandshurica

JI Lanzhu¹,XIAO Dongmei^1,2,WANG Miao¹

2005, 16(03):  408-412 . 

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This paper studied the photosynthesis characteristics and water use efficiency (WUE) of Fraxinus mandshurica under three years simulated water stresses 85%～100% (CK),65%～85% (MW) and 45%～65% (LW) of field water-holding capacity.The results showed that in comparing with CK,the photosynthesis rate and WUE were higher in treatment MW,but decreased by 7.26% and 1.13%,respectively in treatment LW,indicating that Fraxinus mandshurica could fully exert its photosynthesis potentiality under long-term medium water stress,and was more resistant to moderate than to critical water stress.In treatment CK,the diurnal change ofP_n and WUE was a single and a double peak curve,respectively,while in treatments MW and LW,the diurnal change of Pn was a double peak curve,but that of WUE had no significant peak,which correlated not only to the physiological characteristics of Fraxinus mandshurica under different water stress,but also to the diurnal change of environmental factors.

Population structure and its dynamics of rare and endangered plant Alsophila spinulosa

SONG Ping,HONG Wei,WU Chengzhen,FENG Lei,FAN Hanlan,ZHU Hui,LIN Yongming,ZHANG Qiong

2005, 16(03):  413-418 . 

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This paper analyzed the population structure of Alsophila spinulosa in seven plos by the method of spatial sere substituting for time sere,and measured its spatial distribution pattern and dynamics by applying five aggregate indices,C,K,m*,m*/m and Iδ.The spatial distribution pattern with different quadrat scale was examined,according to the map of individual location.The results indicated that the population structure of Alsophila spinulosa in the seven plots presented growing,stable,adult or senescent type,and the spatial distribution pattern was changed from clump to random with the development of Alsophila spinulosa population.The values of dispersion index Iδ of the population decreased with increasing quadrat scale.

Effects of salinity stress on poplars seedling growth and soil enzyme activity

ZHANG Jianfeng¹,ZHANG Xudong¹,ZHOU Jinxing¹,Franz Makeschin²

2005, 16(03):  426-430 . 

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A pot culture experiment with two clones of poplars (P₁ and P₂) showed that soil salinity had a definite inhibitory effect on the establishment and growth of seedlings.The survival rate,seedling height and weight,and root weight were all declined with increasing soil salinity.When the salinity was 0.2%, 0.4%,0.6% and 0.8%,the shoot growth of P₁ and P₂ decreased by 23.24%,48.56%,70.76% and 83.33%,and 71.77%,83.25%,86.28% and 91.39%,respectively,in comparing with the control.Regressive analyses showed that soil salinity had a linear relationship with chlorophyll content, and a binomial relationship with leaf proline content. The activities of soil β-glucosidase and L-asparaginase were decreased with increasing soil salinity.When the salinity was 0.2%,0.4%,0.6% and 0.8%,the β-glucosidase activity in P₁ and P₂ soils decreased by 10.96%,20.07%,30.96% and 37.44%, and 11.21%,18.94%,34.89% and 41.31%,respectively.The salinity tolerance of P₁ was better than that of P₂.

Effects of NaCl stress on Ca,Mg,Fe and Zn contents of different apple organs

XIA Yang¹,LIANG Huimin¹,WANG Taiming¹,SHU Huairui²,WANG Qinghua¹, CHAI Chuanhua¹

2005, 16(03):  431-434 . 

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The study with two-year-old potted apple tree (Fuji variety with M.hupehensisReld stock) showed that under NaCl stress,the average contents of Ca,Mg,Fe and Zn in different apple organs sampled at 4 periods had no significant changes,while the content ratios of test elements to Na decreased significantly,especially under high NaCl (3‰) stress,which would result in the umbalance of mineral nutrients in the tree.The Ca content of different apple organs under and without NaCl stress was in order of trunk phloem > leaf and vegetative shoot >root > trunk xylem;Mg content was vegetative shoot and root > trunk xylem and phloem,and leaf;Fe content was root > leaf > trunk phloem and vegetative shoot > trunk xylem;Zn content was vegetative shoot > leaf > root and trunk phloem > trunk xylem.The element contents under NaCl stress showed different degrees of fluctuation, comparing with the control.

Alfalfa growth and its relation with soil water status in loess hilly and gully region

CHENG Jimin,WAN Hui′e,WANG Jing

2005, 16(03):  435-438 . 

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This paper studied the dynamics of alfalfa growth and its relation with the excessive depletion and resumption of soil water in loess hilly and gully region.The results showed that alfalfa could grow in this region for 10 years,being most flourishing at the forth and fifth year,but declined gradually because of the excessive depletion of soil water.From 0 to 35 cm above ground,the stem biomass was higher than the leaf biomass,and the ratio of stem to leaf was 1.7∶1; at 40 cm above ground,the biomass of stem and leaf was equal; and from 45 to 90 cm above ground,the leaf biomass was higher than the stem biomass,with the ratio of leaf to stem 1.42∶1.The soil dry layer was not distinct in first two years of alfalfa growth,but getting thicker with time,being from 110 cm in third year to 260 cm in seventh year,with a 4.6%～6.2% of soil water content.It took 5 years for the natural resumption of soil water in degraded alfalfa grassland,and soil water content was increased with time.

Dynamics of soil nitrogen,phosphorus and organic matter in alfalfa-crop rotated farmland in semiarid area of Northwest China

WANG Jun^1,2，LI Fengmin²,JIA Yu²,WANG Yajun²

2005, 16(03):  439-444 . 

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Pasture-crop rotation is regarded as a key planting system in the semiarid area of China's Loess Plateau.This paper studied the dynamics of soil nitrogen,phosphorus and organic matter within the two years of alfalfa-crop rotation.The results showed that in comparing with continuous alfalfa planting,alfalfa-crop rotation induced a decline of soil total nitrogen and organic matter contents by 5.4% and 19.5%,and 46.8% and 28.2%, respectively, in the first and second year,but no significant difference was found in soil total phosphorus.Soil nutrient availability was improved due to the rotation.In the first and second year of rotation,soil nitrate nitrogen and available phosphorus contents increased by 15.5% and 159.1%,and 44.5% and 48.0%,respectively.Planting spring wheat could maintain soil fertility,the second was fallow and planting potato,while planting corn accelerated the depletion of soil total nitrogen,organic matter and available phosphorus.As a result,in the alfalfa-crop rotation,planting spring wheat could be more available to the maintenance of soil fertility.

Soil evaporation under perforated plastic mulch

LI Yi^1,3,WANG Quanjiu^3,4,WANG Wenyan⁴,SHAO Ming′an^2,3

2005, 16(03):  445-449 . 

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In arid and semiarid regions of northwestern China,where evaporation exceeds precipitation,perforated plastic mulches are widely used to decrease soil water evaporation.To determine the effects of various perforated plastic mulches on soil water evaporation after irrigation,a soil column experiment was conducted,which consisted of six mulches with different perforated rates and four levels of irrigation,and the soil water evaporation from each soil column was measured.The results showed that with 100% perforated mulch,the cumulative evaporation was 2.8～48.5 times higher than that of the control,and increased with increasing irrigation amount.There was a linear relationship between cumulative evaporation and time,which followed the Gardner's theory of bare soil evaporation.A three-factor (evaporation time,perforated rate and irrigation amount) function of cumulative evaporation and the functions of relative cumulative evaporation and cumulative evaporation per unit hole area film were established,which fitted the observed data very well.

Effects of simulated acid rain on physiological and biochemical characters of eggplant,the host plant of Tetranychus cinnabarinus

ZHANG Jianping^1,2,WANG Jinjun¹,ZHAO Zhimo¹,CHEN Yang¹, DOU Wei¹

2005, 16(03):  450-454 . 

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In a series of laboratory trials,this paper studied the responses of eggplant (Solanum melongena),the host plant of carmine spider mite Tetranychus cinnabarinus,to different pH values simulated acid rain.The results showed that with the increasing acidity of simulated acid rain,the CAT activity and the contents of P and soluble protein in egg plant leaves increased significantly first,reaching the highest at pH 4.0 or 3.0,and then decreased; while the POD activity and soluble sugar content were in adverse.The reduced sugar content and SOD activity of eggplant leaves increased,but the pH value decreased with increasing acidity of acid rain.Acid rain had no effect on leaf water content.Among the test indices,leaf POD was most insensitive to the acid rain,followed by leaf pH,SOD and CAT,while the others were very sensitive.Weak acid rain (pH > 4.0) promoted the protective ability of eggplant leaf and its growth,and the growth of T.cinnabarinus was also promoted because of the changed contents of soluble sugar,P and soluble protein in eggplant leaves being more favorable to its eating; while strong acid rain (pH<3.0) inhibited the growth of both host plant and mite.

Resource and ecological distribution of ectomycorrhizal fungi under pine forests of Huangshan Mountain district

KE Lixia，LIU Birong

2005, 16(03):  455-458 . 

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Pinus massoniana and Pinus taiwanensis are the most common and important tree species in the Huangshan Mountain district,and ectomycorrhizae plays an important role in their forestation.Our investigations in 1998～2003 showed that under the pine forests of this district,there were 43 species of ectomycorrhizal fungi belonging to 10 families and 17 genera,of which,43 were under Pinus massoniana forest, and 12 under Pinus taiwanensis forest.Only a few species were found under young Pinus massoniana forest,with the dominant of Pisolithus tinctorius (Pers.) Coken and Rhizopogon spp.,but under mature Pinus massoniana forest, there were plentiful species,with the dominant of Russulaceae, Amanitaceae,Boletaceae and Canthurellaceae.The relationships between woody species and ectomycorrhizal fungi,and between fungi distribution and temperature,moisture and soil condition were discussed in this paper,which would benefit to the further studies on the effects of different ectomyrrhizal fungi to Pinus massoniana and Pinus taiwanensis forests.

Effects of arbuscular mycorrhiza on drought tolerance of Poncirus trifoliata

WU Qiangsheng,XIA Renxue,HU Zhengjia

2005, 16(03):  459-463 . 

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This paper evaluated the effects of arbuscular mycorrhizal colonization on the growth and drought tolerance of Poncirus trifoliata in a potted culture under natural water stress and resuming water supply.The results showed that the arbuscular mycorrhizal colonization by Glomus mosseae- 93 could significantly increase the plant height,stem diameter,and fresh weight of myocrrhizal plant.By the end of the experiment,the survival percentage of transplanted mycorrhizal plant was 7.1% higher than that of nonmyocrrhizal plant.During natural water stress and resuming water supply,the soluble sugar and soluble protein contents and the SOD,POD and CAT activities of root or leaf were higher or significantly higher in mycorrhizal than in nonmycorrhizal plant,suggesting that arbuscular mycorrhizal colonization could improve the osmoregulatory response of myocrrhizal plant,enhance its protective capability,and depress its cell membrane oxidative damage to lipids. Consequently, the drought tolerance of inoculated Poncirus trifoliata was enhanced. It was considered that the functional mechanism of arbuscular mycorrhizal fungus in enhancing the drought tolerance of host plant was closely related to the protective systems such as SOD,POD,CAT,and soluble protein,etc.

Redistribution patterns of black soil in hillslope landform of Northeast China:A ¹³⁷Cs study

FANG Huajun^1，2,YANG Xueming¹,ZHANG Xiaoping¹,LIANG Aizhen^1，2

2005, 16(03):  464-468 . 

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In the black soil region of Northeast China,soil and water loss is quite serious, but not fully investigated due to the lack of reliable methods.¹³⁷Cs technology is a good one to study the medium-and long term erosion and sedimentation rates and the spatial redistribution of soil.With this technology and the existing calibration models,this paper studied the redistribution patterns of black soil in a typical hillslope landform of Northeast China.The results showed that in the study area,the reference ¹³⁷Cs value was 2232.75 Bq·m^-2,intervenient the background values in the Yangtse River Delta and Loess Plateau;and the¹³⁷Cs areal activity had a great differentiation in horizontal and vertical directions,being the lowest in the shoulder-slope positions,which suggested that the summits and back-slope positions suffered weak erosion,and some of the eroded soils were redeposited in foot-slope and toe-slope positions.The vertical distribution of ¹³⁷Cs in soil profile ranged from 20 cm on a shoulder-slope to 80 cm on a toe-slope position,indicating a significant erosion and deposition.Estimations with four existing calibration models showed that PM model underestimated while MBM-1 model overestimated the soil erosion rates very obviously,and both MBM-2 and MBM-3 gave similar and reasonable estimations.

Spatial and temporal differentiation of mountainous soil organic matter δ¹³C in Dinghushan Biosphere Reserve

CHEN Qingqiang^1,2,SHEN Chengde²,SUN Yanmin²,PENG Shaolin³, YI Weixi², LI Zhi'an³,JIANG Mantao²

2005, 16(03):  469-474 . 

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Based on the determinations of soil organic matter (SOM) content,SOM Δ¹⁴C,and SOMδ¹³C of the samples collected by thin-layered sampling method, this paper studied the spatial and temporal differentiation of SOM δ¹³C in the soil profiles at different altitudes in Dinghushan Biosphere Reserve.The results showed that the vertical differentiation of SOM δ¹³C at different altitudes was controlled by the development of soil profile,and closely correlated with the composition of SOM and its turnover processes.The fractionation of carbon isotope was happened during both the transformation of vegetation debris into topsoil organic matter (OM) and its regeneration after the topsoil buried,which resulted in a significant increase of SOM δ¹³C.Relative to plant debris δ¹³C,the δ¹³C increment of topsoil OM was more dependent on its turnover rate.Both the δ¹³C of plant debris and topsoil OM increased with altitude,indicating the regular variation of vegetations with altitude,which was consensus to the vertical distribution of vegetations in Dinghushan Biosphere Reserve.Soil profiles at different altitudes had similar characteristics in vertical differentiation of SOM δ¹³C, vertical distribution of SOM content,and increasing apparent age of SOM ¹⁴C with soil depth,which were resulted from the successive turnover of SOM during the development of soil profile.The maximum depth of SOM δ¹³C in soil profile was different in origin and magnitude with the penetration depth of ¹⁴C produced by nuclear explosion in the atmosphere,indicating the controlling effects of topography and vegetation on the distribution of SOM carbon isotope with soil depth.

Changes of land use and landscape pattern in Taihu Lake Basin

WAN Rongrong^1，2,YANG Guishan¹

2005, 16(03):  475-480 . 

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Based on three sets of land use data (1985,1995 and 2000),and by means of the techniques of remote sensing,geographical information system (GIS),and landscape ecology,this paper studied the changes of land use and landscape pattern from 1985 to 2000 in Taihu Lake Basin located at Yangtse River Delta.The results showed that in past 15 years,the farmland in this Basin decreased,while the built-up areas,woodland,grassland and water body increased.The decrease of the farmland occupied 89.64% of total decrement, while the increase of the built-up areas accounted for 79.21% of total increment.Under the disturbance of human activities,the landscape structure and landscape heterogeneity in Taihu Lake Basin changed greatly.The patches density decreased from 0.996 to 0.930,diversity indices decreased from 1.127 to 1.113,evenness indices decreased from 62.891% to 62.109%; while the edge density increased from 4.408 to 4.459,dominance indices increased from 0.665 to 0.679,and shape indices increased from 1.540 to 2.796.The landscape heterogeneity varied with different kinds of landscape, indicating the complexity of landscape ecosystem.In all kinds of landscapes, farmland and grassland had the highest values of diversity indices.The diversity indices of water bodies decreased firstly and then increased,while those of built-up areas were in adverse.The evenness index was decreased in the order of woodland > farmland > grassland > water body > builtup areas.Population,economy and policies were the driving forces of the dynamic changes of landscape pattern in Lake Taihu Basin during past 15 years,and land use change in the Basin caused distinct landscape effects,such as landscape fragmenting,edge effects intensification,and environmental quality declining.The mode of land use should be adjusted in landscape scale to rehabilitate and reconstruct the landscape ecosystems in Taihu Lake Basin.

Ditches protection in lake network based on landscape ecology

FAN Yingying,LIU Yong,GUO Huaicheng，MAO Guozhu

2005, 16(03):  481-485 . 

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As a typical corridor landscape in lake network,ditch is an important component of lake ecosystem.In recent years,the ecosystem quality of Hanyang lake network in Wuhan City becomes worse and worse,mainly caused by the degradation of ditch corridor's function.In order to restore its function,this paper made an optimized design of the ditches' landscape pattern on the basis of landscape ecology theories such as corridor scale effect,heterogeneity,edge effect and ecological rehabilitation,and the analyses of ditches status.The contents were to control the water quality in the whole area in a larger scale,to dredge and rebuild the ditches to strengthen the corridor function,and to project the banks of ditches to enhance the anti-disturbance ability.The study indicated that the theories of landscape ecology should be used reasonably in the ditches protection in lake networks.

Relationships between climate change and rice development and its yield formation:A simulation study

LIU Taoju,YIN Xinyou,QI Changhan,TANG Jianjun,CHEN Meiqiu

2005, 16(03):  486-490 . 

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With the application of mechanistic model (RICAM 1.3,RIce growth Calendar Model),this paper simulated the rice development and its yield formation under different climatic conditions at multi-locations of Asia.A threestage Beta model (3s-Beta) was developed to predict the flowering stage of rice and to describe its three successive phases of photo-thermal response,i.e.,basic vegetative phase,photoperiod-sensitive phase,and post photoperiod-sensitive phase.The 1980～1989 multi-location data of Morioka (Japan,39°43′N),Nanchang (China,28°36′N) and Los Banos (Philippines,14°11′N) were used to verify the suitability of the model in studying eco-system change.Comparisons of simulated results with observed data showed that this model could generally predict the eco-physiological processes of rice,and performed very well over a wide range of environments.

An ecological model for predicting amylose content in rice grain

LI Weiguo,ZHU Yan,DAI Tingbo,CAO Weixing

2005, 16(03):  491-495 . 

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By planting rice varieties Indica and Japonica under different ecological environments in China,Japan and Thailand,this study analyzed the relationships between the grain amylose content of test varieties and the environmental factors including latitude,altitude,temperature and solar radiation during grain filling period,established the factor-driven equations for amylose accumulation in rice grain,and developed an ecological model for predicting rice grain amylose content.The model was validated by using the data of different years,sites and varieties,with the RMSE being 0.4% and 0.5% for the grain amylose content of Indica and Japonica,and 0.39% and 0.50% for their planting areas,respectively.The results indicated that the model was accurate and applicable.

Effects of elemental sulphur and dicyandiamide on mitigating NO₃^--N leaching loss from vegetable soil

ZHAO Yanwen^1,2,LIU Changzhen^1,2,HU Zhengyi²,GAO Yimin³, WANG Cairong³, BI Dongmei¹

2005, 16(03):  496-500 . 

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In a pot experiment with allium as test plant and NH₄HCO₃ as nitrogen source,this paper studied the effects of element sulphur（S₀）and dicyandiamide (DCD) on mitigating the NO₃^--N leaching loss from soil and on soil inorganic nitrogen (NO₃^--N and NH₄⁺-N) content.The results showed that within the 12 weeks of the experiment,the cumulative leaching loss of soil NO₃^--N in treatments S₀+DCD and S₀ was 83%～86% and 83% lower,while that of soil NH₄⁺-N was 16.8～21.0 mg·pot^-1 and 20.4～25.0 mg·pot^-1 higher than CK,respectively,and the cumulative loss of soil (NH₄⁺+NO₃^-)-N was 60% lower.By the end of the experiment,soil inorganic nitrogen content in treatments S₀ +DCD and S₀ was 79.9%～85.4% and 74.9～82.6% higher than CK,respectively.The cumulative leaching loss of inorganic N in treatment S₀ +DCD was 4.6%～14.4% and 15.4%～30.1% lower,and the soil inorganic nitrogen content by the end of the experiment was 6.1% and 16.8%～36.0% higher than that of treatments S₀ and DCD,respectively.Similar results were obtained when S₀ was replaced by Na₂S₂O₃,but not by Na₂SO₄.The fact that the application of S₀ could obviously decrease the NO₃^--N leaching loss from soil could be contributed to the inhibitory effects of S₂O₃^2- and S₄O₆^2- originated from S₀ oxidation in soil on the nitrification of NH₄⁺-N.S₀ could retard the decomposition of DCD due to the effect of its oxidized products S₂O₃^2- and S₄O₆^2-,and thus,extend the inhibitory effect of DCD on NH₄⁺-N nitrification.It is suggested that S₀ combined with DCD could be used as an effective nitrification inhibitor to control the NO₃^--N leaching loss from vegetable soils.

Foraging habitat selection of Otis tarda dybowskilduring its breeding season

ZHAO Jiang¹,WAN Dongmei²,WANG Haitao³,GAO Wei³

2005, 16(03):  501-504 . 

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From April to July of 2000 and 2001,the authors studied the foraging habitat selection of Otis tarda dybowskil in the southeast Keerqin of Inner Mongolia by sampling method.The results showed that whether at burned or at nonburned grassland,the foraging habitat of Otis tarda dybowski had the same feature in vegetation structure,the plant height was about 13 cm on average,with the highest of 30 cm,and there were abundant species of plants and insects with big density that the bird favored to eat.The bird more concerned with the abundance of plants at burned grassland,while that of insects at non-burned grassland.

Field attraction effects of different trapping methods on Monochamus alternatus

WANG Sibao^1,2,LIU Yunpeng³,FAN Meizhen³,MIAO Xuexia¹,ZHAO Xieqiu³,LI Zengzhi³,SI Shengli¹,HUANG Yongping¹

2005, 16(03):  505-508 . 

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A comparative study on the field attraction effects of different attractant, trap,lure and controlled-releasing amount on Monochamus alternatus showed that four test attractants had a certain trapping ability to Monochamus alternatus,among which,MA2K05 was the strongest,with a mean capture efficiency of 26.3individuals each trap and being attractive to other species of Loleoptera and Hemiptera; MA2K13 took the second place,with 21.3 individuals each trap; while MA2K11 was the weakest,with 13.8 individuals each trap.Among the three lures tested,lures C (60 ml plastic cup with 2 of 5 cm round holes on the cover) and B (20 ml specified controlledreleasing plastic bottle) had a comparatively stronger effect,with a capture efficiency of 34.25 and 20.3 individuals each trap,respectively; while lure A (20 ml specified controlled-releasing plastic bottle,the releasing amount being smaller than that of lure B) was the weakest,with 14.7 individuals each trap.Because the attractant volume of lure C was 1.5 times larger than that of lures B and A,and the attractant for lure C was appended every 3～5 d, while that for lures B and A could be used for more than a month with once appended,lure B was the best on the whole.As for the test traps, Xuanzhou trap was superior to imitated Japanese trap,with a trapping efficiency of 36.4 and 9.7 individuals each trap,respectively.The attractiveness of attractants was not significantly enhanced when the dosage was increased from 20 ml to 80 ml,but significantly improved when it was up to 120 ml.

Feeding behavior of Serangium japonicum (Coleoptera:Coccinellidae),a predator of Bemisia tabaci (Homoptera:Aleyrodidae)

YAO Songlin^1,2,REN Shunxiang¹,HUANG Zhen¹

2005, 16(03):  509-513 . 

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Serangium japonicum is an important predator of whiteflies in China.In this study,the Bemisia tabaciattacking behavior of S.japonicum adults and larvae was observed by a videocassette recorder.The results showed that the predatory behavior of S.japonicum adults was characteristic with six events,i.e.,walking,feeding,clearing,resting,vibrating wings,and excreting.The starved larvae of S.japonicum was fond spending all times in feeding and walking on host eggs,with no time in resting or clearing throughout the process.The time included in feeding and walking was not significant different among different instars of S.japonicum.The handing time per egg decreased with S.japonicum larvae developed from instar I to Ⅳ,but differed little between instar Ⅲ and Ⅳ.The starved females of S.japonicum spent longer time on egg feeding，but less time on clearing,resting and walking than satiated females.The time for starved female to predate on B.tabaci nymphs and pupae increased as the host nymphs developed.

Effects of herbicides on diversity indices of cotton field arthropod community

2005, 16(03):  514-518 . 

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This paper studied the differences of the diversity,abundance and evenness of arthropod community and sub-community in cotton field among treatments haloxyfork (A),paraquat (B) and contrast (CK).The results showed that in the diversity of phytophagous subcommunity,t _A-CK=3.099 andt_B-CK =2.449 (t>t_0.05=2.228),the difference being significant,and in the diversity of predatory subcommunity,t_A-B=2.260 and t_A-CK=2.377 (t>t _0.05=2.228),the difference being also significant.In the arthropod community and subcommunity,no significant difference was found for A-CK,B-CK and A-B.The abundance of arthropod community t_A-CK=4.359,and that of phytophagous sub-community t_A-CK=2.963,the effect being all significant (t>t_0.05=2.228).No significant difference was found in the evenness of arthropod community and sub-community for A-B,A-CK and B-CK.The biodiversity had the same change trend for treatments haloxyforR (A) paraquat (B) and contrast (CK).

Effects of nitrogen supply on nutritional quality and antioxidative enzyme activities of spinach

ZHANG Yingpeng,LIN Xianyong,ZHANG Yongsong

2005, 16(03):  519-523 . 

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A hydroponic experiment was carried out to study the effects of nitrogen (N) supply on the nutritional quality and antioxidative enzyme activities of spinach.The results showed that when the N supply increased from 4 to 8 mmol·L^-1,the biomass of spinach and its leaf vitamin C (Vc) content increased significantly,but a further increase of the N supply induced an obvious decrease of Vc content.An increasing N supply increased the nitrate content in leaves.The soluble oxalate content in leaves decreased slightly with the N supply from 4 to 8 mmol·L^-1 N,but increased with a further increase of supplied N.Total oxalate content increased firstly,and then decreased with increasing N supply.SOD and POD activities increased with the N level up to 8 mmol·L^-1 N,but drastically decreased with increasing N levels.CAT activity decreased when N level elevated.MDA content decreased firstly and then increased with increasing N levels,while free proline content decreased with increasing N supply.All of these indicated that 8 mmol·L^-1 N was an appropriate N supply level for spinach to improve its biomass, nutritional quality,and resistance.

Effects of Bt corn straw decomposition on soil enzyme activities and soil fertility

WANG Jianwu,FENG Yuanjiao,LUO Shiming

2005, 16(03):  524-528 . 

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An incubation test with the straws of Bt corn 34B24 and its non-transgenic isogenic line 34B23,Bt corn Nongda 61,and non-transgenic Nongda 3138 was conducted to study the potential effects of Bt corn straw decomposition on soil enzyme activities and soil fertility.No significant difference in soil protease and acid phosphatase activities was found between treatments 34B24 and 34B23; but on day 75 of incubation,soil dehydrogenase activity was significantly higher in treatment 34B24 than in treatment 34B23.The same was true for soil invertase activity on days 15,45,60 and 75.Soil urease activity in treatment 34B24 was significantly increased on day 30,but decreased on days 45 and 75.A significant difference in several soil enzyme activities was also observed between the treatments of two Bt corn hybrids and their conventional cultivars at some sampling days.After incubation for 90 days,the contents of soil available P and K were significantly lower in treatment 34B24 than in treatment 34B23.The differences mentioned above resulted from the composition of test corn straws,which may be affected by the Bt gene transformation process.In order to accurately assess the effects of Bt corn straw decomposition on soil ecosystem,a standard classification system of soil enzyme activities should be established for different soil types from different regions.

Effects of Alternaria azukiae on physiological metabolism and active oxygeneliminating enzyme activities of Trifolium repens

LI Zheng,LIU Dengyi,DING Jiahong,WANG Yupeng

2005, 16(03):  529-532 . 

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A pot experiment was installed to study the effects of Alternaria azukiae inoculation on the cell membrane permeability,pigment and MDA contents,and activities of SOD,POD and CAT ofTrifolium repens.The results showed that A.azukiae infection made T.repens leaf tissue increase its cell membrane permeability,electric conductivity,over-oxidation and MDA content,but decrease its pigment content.The electric conductivity and MDA content were positively related with infection time,whereas the pigment content was negatively related with it.Due to the stimulation by A.azukiae,the overoxidation of cell membrane was intensified,which resulted in a large amount of active oxygen accumulated and beyond the defense ability,the active oxygen metabolism system was destroyed,and the balance of protective enzyme system was broken.After 12 days of A.azukiae inoculation,the activities of SOD and CAT decreased by 55.2% and 37.8%,respectively,while the POD activity increased by 1.6 times.

Effects of oxalate on acid phosphatase adsorption and its activity on soil colloids and minerals

ZHAO Zhenhua^1,2,HUANG Qiaoyun³,JIANG Xin²,WANG Daizhang³, GAO Hongjian²,LI Xueyuan³

2005, 16(03):  533-538 . 

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By a batch method,this paper studied the effects of different concentration and pH of oxalate,an important root exudate,on the adsorption of acid phosphatase and its activity on <2 μm colloids of yellow brown soil and latosol,and on minerals goethite and kaolinite.The results showed that the acid phosphatase adsorption by goethite was less affected by the concentration of oxalate; while the adsorbed amount of this enzyme by the other test colloids and kaolinite was sharply decreased with the increasing oxalate concentration (0～5 mmol·L^-1) first,and then gradually increased to the level equal to or less than the blank,which may be related to the coordination type of oxalate on soil colloids and minerals,and their surface charge change and dissolution.In the systems oxalate existed,the adsorbed amount of acid phosphatase by soil colloids and minerals decreased in order of goethite-yellow brown soil > kaolinite > latosol.The pH value for the maximum adsorption of acid phosphatase was between the IEP of the enzyme and the PZC of test colloids and minerals.After the enzyme was immobilized on colloids and minerals,the pH of its maximum specific activity had no change,or shifted to a higher value.

CH₄ and N₂O emission from a winter-time flooded paddy field in a hilly area of Southwest China

JIANG Changsheng^1,3，WANG Yuesi¹,ZHENG Xunhua¹,LI Jing¹,HUANG Yao¹,HAN Guangxuan²,ZHANG Zhongjie²,ZHU Bo²

2005, 16(03):  539-544 . 

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By the method of static opaque chamber/ modified gas chromatography,a oneyear field experiment was conducted to measure in situ the CH₄ and N₂O emission from a winter-time flooded paddy field in a hilly area of Southwest China.Gas samples were taken simultaneously from rice-involved and riceuninvolved plots.The results showed that during rice growth period,the CH₄ emission from the winter-time flooded paddy field was higher than that from other paddy fields,but largely lower than many previous reports for the similar regions in Southwest China.The average flux of CH₄ emission from riceinvolved plots was 22.76±2.76 mg CH4·m^-2·h^-1 during rice growth period,9.64±1.17 mg CH₄·m^-2·h^-1 per year,and 1.43±0.20 mg CH₄·m^-2·h^-1during non-rice growth season; while that from riceuninvolved plots was only 2.03±0.18 mg CH₄·m^-2·h^-1 per year,markedly lower than those from riceinvolved plots.During rice growth season,the mean emission rate of CH₄ and N₂O was 4.53±0.38 mg CH₄·m^-2·h^-1and 32.01±5.02 μg N₂O·m^-2·h^-1 from rice-uninvolved plots,but reached to 22.76±2.76 mg CH₄·m^-2·h^-1 and 73.04±5.03 μg N₂O·m^-2·h^-1 from rice-involved plots,respectively.Rice involvement resulted in 302% increment of CH₄ and 128% increment of N₂O mission.There was a clear trade-off between CH₄ and N₂O emission in paddy fields.Even with a span of 500 years,our calculation showed that in this winter-time flooded paddy field,the GWP contributed by N₂O production was 7.9% of the CH₄ contribution,and thus,the greenhouse effect of N₂O production from this field was very small.

Responses of soybean to O₃,CO₂ and their combination

BAI Yueming,WANG Chunyi,WEN Min

2005, 16(03):  545-549 . 

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With cultivar “Zhonghuang 14" as test crop,this paper studied the effects of CO₂ and/or O₃ on the growth and development of soybean （Glycine max L.）in an open top chamber.The results showed that an increasing CO₂ concentration could defer the leaf's O₃ injury,and relax the injury degree. After treated with CO₂ for 20 days,the stoma resistance and transpiration rate of soybean leaves had little difference with CK.Only when fumed with high concentration CO₂ and O₃,the stoma became closed,stoma resistance increased,and transpiration rate decreased obviously.Compared with ambient atmospheric CO₂ and O₃ (CK),doubled CO₂ significantly increased the dry matter accumulation and grain yield,reduced the coarse fat and raw protein contents of grain,but the harvest index had no obvious difference; while doubled O₃ decreased the dry matter accumulation,grain yield and harvest index of soybean,reduced the coarse fat content,but increased the raw protein content of grain.The interaction of doubled CO₂ and O₃ had no obvious effects on the dry matter accumulation,grain yield and harvest index of soybean,but reduced the grain raw protein content to a certain extent and increased the coarse fat content obviously.

Distribution,migration and purifying effect of cadmium in artificial Avicennia marina wetland system

CHEN Guikui¹,CHEN Guizhu²

2005, 16(03):  550-554 . 

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An artificial mangrove Avicennia marina wetland was set up in a greenhouse, and an irrigation experiment with synthetic wastewater was performed to research the behavior of cadmium in the artificial wetland system.The synthetic wastewater C₁ had the characteristics and strength similar to normal municipal sewage,while C₅ and C₁₀ had the nutrients and heavy metals as five and ten times as those in C₁,respectively.The control was of 15‰ salinity.All the test wastewater was quantitatively irrigated weakly for a year.The results showed that the cadmium in the synthetic wastewater discharged into the system was mainly stagnated in soil subsystem (87.67%～96.74%),and only a small portion (0.43%～3.23%) migrated into plants and litters.After a year trial,the Cd content in roots was more than that in stems and leaves.The artificial Avicennia marina wetland system did have a significant effect on purifying cadmium in synthetic wastewater,and the purification rate for C₁,C₅ and C₁₀ was 90.43%，97.17% and 97.06%, respectively.

A new precipitation distribution hydrological model and its application

ZHANG Shengtang^1,2, KANG Shaozhong^1,3,LIU Yin²

2005, 16(03):  555-558 . 

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In distribution hydrological models,precipitation is the key input data for analyzing and computing hydrological processes.Finding a way to produce distribution precipitation data is a hotspot in hydrological research.This paper presented the hypothesis that the distribution of precipitation on the earth surface is the result of the effects of atmosphere system and terrain. Moreover, the spatial distribution of natural precipitation is a group of concentric ovals on the flat earth surface,and has a definite centre with maximum precipitation not affected by terrain.Supporting by the hypothesis, this paper established a new precipitation distribution hydrological model which could simulate the spatial distribution of precipitation,and modified the terrain effect on precipitation through Newton interpolation.The position of the precipitation centre and its precipitation amount were simulated in first time,and thus,the model could have a practical value in basin storm analysis and realtime runoff forecasting.The model was tested by the precipitation data of the Xichuan river basin in the Loess Plateau,which indicated that the model had a high precision.

Effects of UV-B radiation enhancement on DNA damage of three red-tide microalgae species

CAI Hengjiang¹,TANG Xuexi¹,ZHANG Peiyu^1,2

2005, 16(03):  559-562 . 

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The ecotoxicological and biochemical study withHeterosigma akashiwo, Alexandrium tamarense and Skeletonema costatum showed that the test three species of red-tide microalgae had different sensitivities to UVB radiation enhancement,and the order from high to low was Heterosigma akashiwo, Alexandrium tamarense and Skeletonema costatum.The DNA damage of algal cells increased with UV-B radiation enhancement,being more notable in Heterosigma akashiwo than in Alexandrium tamarenseand Skeletonema costatum,and in Alexandrium tamarensethan in Skeletonema costatum.The DNA damage of Heterosigma akashiwo and Alexandrium tamarense could be significantly repaired (P<0.05) after 6 days of UV-B radiation removal,and that of Skeletonema costatum could be significantly repaired (P<0.05) after 3 days,which illustrated that the DNA damage of three red-tide microalgae species could not indicate the damaged degree of marine microalgae resulted from UV-B radiation enhancement.

Bioavailability of cadmium in seawater to Paralichthys olivaceus

ZHAO Yuanfeng,L Jingcai,WU Yichun,SONG Xiaoyang,LIU Changfa,WANG Fan,ZHAO Chong,ZHENG Wei

2005, 16(03):  563-567 . 

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With exposure experiment,this paper studied the accumulation and elimination of cadmium (Cd) in the viscera,muscle and gill of Paralichthys olivaceus,and the effects of TOC concentration in seawater on the Cd accumulation.The results showed that when the exposure concentration of Cd was 0.5 mg·L^-1,its accumulation in test tissues increased with time,and reached equilibrium on the 10th day.The accumulation was in order of viscera (147.73 mg·kg^-1DW) > gill (15.55 mg·kg^-1DW) > muscle (4.578 mg·kg^-1DW),which meant that viscera was the main place for Cd accumulation. Determinations after moving the fish into clear seawater on the 13th day of exposure showed that due to depuration,the Cd accumulation in test tissues decreased with time.On the 15th day after moving,the Cd elimination was in order of viscera (80.66%) > gill (73.66%) > muscle (56.84%),suggesting that the Cd accumulation in Paralichthys olivaceus could be reduced to meet safe food standard.The TOC concentration in seawater had a significant effect on Cd accumulation,i.e.,the accumulation of Cd decreased significantly with increasing TOC concentration,demonstrating that the TOC in seawater could decrease the bioavailability of cadmium.

Alien species invasion in Southern China and its countermeasures

FAN Jihui^1,2,JIANG Li^1,2,CHENG Genwei¹

2005, 16(03):  568-572 . 

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Alien species invasion may cause serious ecological damage,resulting in ecological crisis and biodiversity comedown,and further menacing existing human environment.At present,the invasion of alien species has brought very serious damage to China's environment and society.The direct annual loss of its agro-forestry industry accounts for 574 billion RMB.Taking the alien species in Southern China as an example,this paper analyzed the bioinvasion approaches,mechanics and damages,and aiming at the characters of invaded area and concerned ecosystems and species,proposed several prevention measurements,i.e.,pay attention to the phenomena of bio-invasion and to the basic researches on it; intensify the legislation and establish scientific strategies for introducing alien species; enforce the quarantine on invasive species and establish countrywide monitoring system on alien species; enhance people's defending consciousness; and strengthen international cooperation and collaboration.

Maintaining mechanism of species diversity of land plant communities

SHANG Wenyan,WU Gang,FU Xiao,LIU Yang

2005, 16(03):  573-578 . 

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The maintaining mechanism of species diversity of land plant communities is a key and advancing edge in biodiversity study.Botanists and ecologists have presented many hypotheses and theories with controversies,and no general theory system was available.In this paper,the problem was reviewed mainly on two scales.The first was big spatial scale,aiming at the physical and natural factors that affect the species diversity,including histories and ages of plant communities,gradient changes such as latitude gradient,water gradient,altitude gradient and soil nutrients gradient,area effect,and isolation; and the second was concentrated on a special plant community,and mainly discussed the relationships of biodiversity with biotic factors (primary productivity,relationship between species,and gap dynamics) and abiotic factors (succession,disturbance and spatial heterogeneity,and human activity).

Farmland nitrogen loss and its control strategies from the view of water environment

JIN Jie,YANG Jingping

2005, 16(03):  579-582 . 

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Nitrogen is a major factor in maintaining crop yield and getting better economic return,but its over-and unreasonable use may cause severe environmental pollution.From the view of water environment,this paper discussed the current effects of farmland nitrogen (N) loss on water pollution,the passes and mechanisms of farmland nitrogen loss,and its control strategies.To reduce the N surface runoff and leaching,effective measures should be taken,which include cutting down the paths from the source to transportation,and taking integrated measures to control N pollution.The BMPs (Best Management Practices) methods for N control suitable to China's situation were discussed on the basis of nitrogen source pollution rate.

Phosphatase activities in rice-planting meadow brown soil and their responses to fertilization

SHEN Jupei^1,2,CHEN Zhenhua^1,2,CHEN Lijun¹

2005, 16(03):  583-585 . 

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This study is aimed to investigate the activities of phosphomonoesterase (acid-,neutral-,and alkaline-),phosphodiesterase and phosphotriesterase in a rice-planting meadow brown soil at the lower reach of Liao River,and their responses to different fertilization treatments.The results showed that there was no significant difference in soil total P and organic P contents among all treatments,but soil available P content was significantly higher in treatment OM than in other treatments.Soil acid-and neutral phosphomonoesterase had a higher activity than alkaline phosphomonoesterase and phosphodiesterase, while phosphotriesterase had the lowest activity.No significant difference was found in phosphatase activities between different fertilization treatments.Soil acid phosphomonoesterase activity had a significant correlation with soil total P and available P contents,while soil phosphodiesterase activity significantly correlated with soil organic P content.

Effects of different light source and dark-adapted time on phototactic behavior of cotton bollworms (Helicoverpa armigera)

JING Xiangfeng,LUO Feng,ZHU Fen,HUANG Qiuying,LEI Chaoliang

2005, 16(03):  586-588 . 

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In this paper,the phototactic behaviors of different emergence period Helicoverpa armigerawere studied in a phototactic box.The results showed that under the five test wavelength lights,different emergence period female and male moths had no significant difference in their phototactic behaviors. The phototactic rate differed significantly when the dark-adapted time was between 15 and 30 min,but had no significant difference among 30,45 and 60 min.No significant difference was also found in phototactic rate between dark-adapted time 0 and 15 min under test wavelength lights except green one (500～565 nm).

Effects of artificial tending on Pinus tabulaeformis forest growth and its structural characteristics.

CAO Yun, YANG Yie, SONG Bingyu, HUANG Heping, YANG Mingbo, ZHENG Min

2005, 16(3):  397-402. 

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The investigation on the growth status,community composition,and structural characteristics of Pinus tabulaeformis forest artificially tended for six years showed that there were significant differences in the average DBH,height,and crown size of the forest among the treatments DA (trimming without intermediate cutting),FA (trimming and intermediate cutting) and CK (without trending).Treatment FA had the highest values of average DBH (7.8?0.29 cm),height (5.5?0.09 m) and crown size (249?7.24 cm),while the CK had the lowest ones.The average biomass of new leaf (1 year old),old leaf (2 or more year old),and branch per tree increased significantly (P<0.01) with enhancing tending treatments.The aboveground biomass of treatment FA was the biggest (44.0 t穐m^-2),and that of CK was the smallest(14.9 t穐m^-2).The leaf length and SLA at the early and terminal stages of development (May,June and September) had significant difference among the treatments,and the amount of community composition and the cover degree of undergrowth plants increased evidently under artificial tending treatments.

Niches of several mangrove species in Dongzhai Harbor of Hainan Island.

LIAO Baowen, LI Mei, ZHENG Songfa, CHEN Yujun, ZHONG Cairong, HUANG Zhongqi

2005, 16(3):  403-407. 

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Employing the succession series of Kandelia candel-Aegiceras corniculatum community in non indigenous species Sonneratia apetala extension area as resource axes,and with three commonly used calculation formulae,this paper determined the niche breadth and overlap of mangrove populations.The results showed that the niche breadth decreased in order of Aegiceras corniculatum (3.8357) > Kandelia candel (3.3421) > Bruguiera gymnorrhiza (3.3180) > Avicennia marina (3.0975) > Sonneratia apetala (2 9137) >Sonneratia caseolaris (205724) > Ceriops tagal (1.8523) > Rhizophora stylosa (1.6897) > Bruguiera sexangula (1.0000),which could indicate the ecological adaptability and distribution range of the species.The niche overlap among K.candel,A.corniculatum,B.gymnorrhiza and A.marina was the largest,suggesting the intense competition among them,followed by the niche overlap of S.apetala with S.caseolaris,A.corniculatum,K.candeli and A.marina,S.apetala with R.stylosa and B.sexangula,S.apetala with C.tagal,and S.apetala with B.sexangula.

Effects of simulated water stress on photosynthesis rate and WUE of Fraxinus mandshurica.

JI Lanzhu, XIAO Dongmei, WANG Miao

2005, 16(3):  408-412. 

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This paper studied the photosynthesis characteristics and water use efficiency (WUE) of Fraxinus mandshurica under three years simulated water stresses 85%～100% (CK),65%～85% (MW) and 45%～65% (LW) of field water holding capacity.The results showed that in comparing with CK,the photosynthesis rate and WUE were higher in treatment MW,but decreased by 7.26% and 1.13%,respectively in treatment LW,indicating that Fraxinus mandshurica could fully exert its photosynthesis potentiality under long term medium water stress,and was more resistant to moderate than to critical water stress.In treatment CK,the diurnal change of P n and WUE was a single and a double peak curve,respectively,while in treatments MW and LW,the diurnal change of P n was a double peak curve,but that of WUE had no significant peak,which correlated not only to the physiological characteristics of Fraxinus mandshurica under different water stress,but also to the diurnal change of environmental factors.

Population structure and its dynamics of rare and endangered plant Alsophila spinulosa

SONG Ping, HONG Wei, WU Chengzhen, FENG Lei, FAN Hanlan, ZHU Hui, LIN Yongming, ZHANG Qiong

2005, 16(3):  413-418. 

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This paper analyzed the population structure of Alsophila spinulosa in seven plots by the method of spatial sere substituting for time sere,and measured its spatial distribution pattern and dynamics by applying five aggregate indices, C,K,m ^*,m ^*/m and I δ.The spatial distribution pattern with different quadrat scale was examined,according to the map of individual location.The results indicated that the population structure of Alsophila spinulosa in the seven plots presented growing,stable,adult or senescent type,and the spatial distribution pattern was changed from clump to random with the development of Alsophila spinulosa population.The values of dispersion index I δ of the population decreased with increasing quadrat scale.

Transpiration water consumption of young Platycladus orientalis and Robinia pseudoacacia trees and their correction functions under different water supply

WANG Jinxin, HUANG Baolong, WANG Mingchun, WANG Dihai

2005, 16(3):  419-425. 

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Through artificial water control in the shed of rain free,this paper studied the physiological water requirement patterns of 2～3 years old Platycladus orientalis and Robinia pseudoacacia trees during their growth period,and the relationships between their transpiration water consumption and soil water supply.The results showed that the transpiration water consumption of Robinia pseudoacacia was increased with increasing soil water supply within the range of 40%～100% of field water holding capacity.Its maximum transpiration water consumption was at the early and accelerating growth stages,accounted for 80.5% of total annual water consumption.The transpiration water consumption of Robinia pseudoacacia was 5.13 times as much as that of Platycladus orientalis.Platycladus orientalis had a peak value of transpiration water consumption when the soil moisture content was 40%～100% of field water holding capacity.Its transpiration water consumption was the maximum at accelerating growth stage,accounted for 46.27% of total annual water consumption,next at later growth stage,and relatively small at early growth stage.The correction functions of transpiration water consumption to soil water supply and the time soil moisture functions of practical transpiration water consumption under insufficient water supply for two test species were put forward for the first time.

Effects of salinity stress on poplars seedling growth and soil enzyme activity

ZHANG Jianfeng, ZHANG Xudong, ZHOU Jinxing, Franz Makeschin

2005, 16(3):  426-430. 

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A pot culture experiment with two clones of poplars (P₁ and P₂) showed that soil salinity had a definite inhibitory effect on the establishment and growth of seedlings.The survival rate,seedling height and weight,and root weight were all declined with increasing soil salinity.When the salinity was 0.2%,0.4%,0.6% and 0.8%,the shoot growth of P₁ and P₂ decreased by 23.24%,48.56%,70.76% and 83.33%,and 71.77%,83.25%,86 28% and 91.39%,respectively,in comparing with the control.Regressive analyses showed that soil salinity had a linear relationship with chlorophyll content,and a binomial relationship with leaf proline content. The activities of soil β glucosidase and L asparaginase were decreased with increasing soil salinity.When the salinity was 0 2%,0 4%,0.6% and 0 8%,the β glucosidase activity in P₁ and P₂ soils decreased by 10.96%,20.07%,30.96% and 37.44%,and 11.21%,18.94%,34.89% and 41.31%,respectively.The salinity tolerance of P₁ was better than that of P₂.

Effects of NaCl stress on Ca,Mg,Fe and Zn contents of different apple organs

XIA Yang, LIANG Huimin, WANG Taiming, SHU Huairui, WANG Qinghua, CHAI Chuanhua

2005, 16(3):  431-434. 

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The study with two year old potted apple tree (Fuji variety with M.hupehensis Reld stock) showed that under NaCl stress,the average contents of Ca,Mg,Fe and Zn in different apple organs sampled at 4 periods had no significant changes,while the content ratios of test elements to Na decreased significantly,especially under high NaCl (3‰) stress,which would result in the umbalance of mineral nutrients in the tree.The Ca content of different apple organs under and without NaCl stress was in order of trunk phloem > leaf and vegetative shoot >root > trunk xylem;Mg content was vegetative shoot and root > trunk xylem and phloem,and leaf;Fe content was root > leaf > trunk phloem and vegetative shoot > trunk xylem;Zn content was vegetative shoot > leaf > root and trunk phloem > trunk xylem.The element contents under NaCl stress showed different degrees of fluctuation,comparing with the control.

Alfalfa growth and its relation with soil water status in loess hilly and gully region

CHENG Jimin, WAN Hui'e, WANG Jing

2005, 16(3):  435-438. 

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This paper studied the dynamics of alfalfa growth and its relation with the excessive depletion and resumption of soil water in loess hilly and gully region.The results showed that alfalfa could grow in this region for 10 years,being most flourishing at the forth and fifth year,but declined gradually because of the excessive depletion of soil water.From 0 to 35 cm above ground,the stem biomass was higher than the leaf biomass,and the ratio of stem to leaf was 1.7:1; at 40 cm above ground,the biomass of stem and leaf was equal; and from 45 to 90 cm above ground,the leaf biomass was higher than the stem biomass,with the ratio of leaf to stem 1.42:1.The soil dry layer was not distinct in first two years of alfalfa growth,but getting thicker with time,being from 110 cm in third year to 260 cm in seventh year,with a 4.6%～6.2% of soil water content.It took 5 years for the natural resumption of soil water in degraded alfalfa grassland,and soil water content was increased with time.

Dynamics of soil nitrogen,phosphorus and organic matter in alfalfa-crop rotated farmland in semiarid area of Northwest China

WANG Jun, LI Fengmin, JIA Yu, WANG Yajun

2005, 16(3):  439-444. 

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Pasture crop rotation is regarded as a key planting system in the semiarid area of China's Loess Plateau.This paper studied the dynamics of soil nitrogen,phosphorus and organic matter within the two years of alfalfa crop rotation.The results showed that in comparing with continuous alfalfa planting,alfalfa crop rotation induced a decline of soil total nitrogen and organic matter contents by 5.4% and 19.5%,and 46.8% and 28.2%,respectively,in the first and second year,but no significant difference was found in soil total phosphorus.Soil nutrient availability was improved due to the rotation.In the first and second year of rotation,soil nitrate nitrogen and available phosphorus contents increased by 15.5% and 159.1%,and 44.5% and 48.0%,respectively.Planting spring wheat could maintain soil fertility,the second was fallow and planting potato,while planting corn accelerated the depletion of soil total nitrogen,organic matter and available phosphorus.As a result,in the alfalfa crop rotation,planting spring wheat could be more available to the maintenance of soil fertility.

Soil evaporation under perforated plastic mulch

LI Yi, WANG Quanjiu, WANG Wenyan, SHAO Ming'an

2005, 16(3):  445-449. 

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In arid and semiarid regions of northwestern China,where evaporation exceeds precipitation,perforated plastic mulches are widely used to decrease soil water evaporation.To determine the effects of various perforated plastic mulches on soil water evaporation after irrigation,a soil column experiment was conducted,which consisted of six mulches with different perforated rates and four levels of irrigation,and the soil water evaporation from each soil column was measured.The results showed that with 100% perforated mulch,the cumulative evaporation was 2 8～48.5 times higher than that of the control,and increased with increasing irrigation amount.There was a linear relationship between cumulative evaporation and time,which followed the Gardner's theory of bare soil evaporation.A three factor (evaporation time,perforated rate and irrigation amount) function of cumulative evaporation and the functions of relative cumulative evaporation and cumulative evaporation per unit hole area film were established,which fitted the observed data very well.

Effects of simulated acid rain on physiological and biochemical characters of eggplant,the host plant of Tetranychus cinnabarinus

ZHANG Jianping, WANG Jinjun, ZHAO Zhimo, CHEN Yang, DOU Wei

2005, 16(3):  450-454. 

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In a series of laboratory trials,this paper studied the responses of eggplant (Solanum melongena),the host plant of carmine spider mite Tetranychus cinnabarinus,to different pH values simulated acid rain.The results showed that with the increasing acidity of simulated acid rain,the CAT activity and the contents of P and soluble protein in egg plant leaves increased significantly first,reaching the highest at pH 4.0 or 3.0,and then decreased; while the POD activity and soluble sugar content were in adverse.The reduced sugar content and SOD activity of eggplant leaves increased,but the pH value decreased with increasing acidity of acid rain.Acid rain had no effect on leaf water content.Among the test indices,leaf POD was most insensitive to the acid rain,followed by leaf pH,SOD and CAT,while the others were very sensitive.Weak acid rain (pH > 4.0) promoted the protective ability of eggplant leaf and its growth,and the growth of T.cinnabarinus was also promoted because of the changed contents of soluble sugar,P and soluble protein in eggplant leaves being more favorable to its eating; while strong acid rain (pH<3 0) inhibited the growth of both host plant and mite.

Resource and ecological distribution of ectomycorrhizal fungi under pine forests of Huangshan Mountain district

KE Lixia, LIU Birong

2005, 16(3):  455-458. 

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Pinus massoniana and Pinus taiwanensis are the most common and important tree species in the Huangshan Mountain district,and ectomycorrhizae plays an important role in their forestation.Our investigations in 1998～2003 showed that under the pine forests of this district,there were 43 species of ectomycorrhizal fungi belonging to 10 families and 17 genera,of which,43 were under Pinus massoniana forest,and 12 under Pinus taiwanensis forest.Only a few species were found under young Pinus massoniana forest,with the dominant of Pisolithus tinctorius (Pers.) Coken and Rhizopogon spp.,but under mature Pinus massoniana forest,there were plentiful species,with the dominant of Russulaceae,Amanitaceae,Boletaceae and Canthurellaceae.The relationships between woody species and ectomycorrhizal fungi,and between fungi distribution and temperature,moisture and soil condition were discussed in this paper,which would benefit to the further studies on the effects of different ectomyrrhizal fungi to Pinus massoniana and Pinus taiwanensis forests.

Effects of arbuscular mycorrhiza on drought tolerance of Poncirus trifoliata

WU Qiangsheng, XIA Renxue, HU Zhengjia

2005, 16(3):  459-463. 

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This paper evaluated the effects of arbuscular mycorrhizal colonization on the growth and drought tolerance of Poncirus trifoliata in a potted culture under natural water stress and resuming water supply.The results showed that the arbuscular mycorrhizal colonization by Glomus mosseae 93 could significantly increase the plant height,stem diameter,and fresh weight of myocrrhizal plant.By the end of the experiment,the survival percentage of transplanted mycorrhizal plant was 7.1% higher than that of nonmyocrrhizal plant.During natural water stress and resuming water supply,the soluble sugar and soluble protein contents and the SOD,POD and CAT activities of root or leaf were higher or significantly higher in mycorrhizal than in nonmycorrhizal plant,suggesting that arbuscular mycorrhizal colonization could improve the osmoregulatory response of myocrrhizal plant,enhance its protective capability,and depress its cell membrane oxidative damage to lipids.Consequently,the drought tolerance of inoculated Poncirus trifoliata was enhanced.It was considered that the functional mechanism of arbuscular mycorrhizal fungus in enhancing the drought tolerance of host plant was closely related to the protective systems such as SOD,POD,CAT,and soluble protein,etc.

Redistribution patterns of black soil in hillslope landform of Northeast China:A ¹³⁷Cs study

FANG Huajun, YANG Xueming, ZHANG Xiaoping, LIANG Aizhen

2005, 16(3):  464-468. 

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In the black soil region of Northeast China,soil and water loss is quite serious,but not fully investigated due to the lack of reliable methods. ¹³⁷Cs technology is a good one to study the medium and long term erosion and sedimentation rates and the spatial redistribution of soil.With this technology and the existing calibration models,this paper studied the redistribution patterns of black soil in a typical hillslope landform of Northeast China.The results showed that in the study area,the reference ¹³⁷Cs value was 2232.75 Bq穖^-2,intervenient the background values in the Yangtse River Delta and Loess Plateau;and the ¹³⁷Cs areal activity had a great differentiation in horizontal and vertical directions,being the lowest in the shoulder slope positions,which suggested that the summits and back slope positions suffered weak erosion,and some of the eroded soils were re deposited in foot slope and toe slope positions.The vertical distribution of ¹³⁷Cs in soil profile ranged from 20 cm on a shoulder slope to 80 cm on a toe slope position,indicating a significant erosion and deposition.Estimations with four existing calibration models showed that PM model underestimated while MBM₁ model overestimated the soil erosion rates very obviously,and both MBM₂ and MBM₃ gave similar and reasonable estimations.

Spatial and temporal differentiation of mountainous soil organic matter δ ¹³C in Dinghushan Biosphere Reserve.

CHEN Qingqiang, SHEN Chengde, SUN Yanmin, PENG Shaolin, YI Weixi, LI Zhi'an, JIANG Mantao

2005, 16(3):  469-474. 

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Based on the determinations of soil organic matter (SOM) content,SOM Δ¹⁴C,and SOM δ¹³C of the samples collected by thin layered sampling method,this paper studied the spatial and temporal differentiation of SOM δ¹³C in the soil profiles at different altitudes in Dinghushan Biosphere Reserve.The results showed that the vertical differentiation of SOM δ¹³C at different altitudes was controlled by the development of soil profile,and closely correlated with the composition of SOM and its turnover processes.The fractionation of carbon isotope was happened during both the transformation of vegetation debris into topsoil organic matter (OM) and its regeneration after the topsoil buried,which resulted in a significant increase of SOM δ¹³C.Relative to plant debris δ¹³C,the δ¹³C increment of topsoil OM was more dependent on its turnover rate.Both the δ¹³C of plant debris and topsoil OM increased with altitude,indicating the regular variation of vegetations with altitude,which was consensus to the vertical distribution of vegetations in Dinghushan Biosphere Reserve.Soil profiles at different altitudes had similar characteristics in vertical differentiation of SOM δ¹³C,vertical distribution of SOM content,and increasing apparent age of SOM ¹⁴C with soil depth,which were resulted from the successive turnover of SOM during the development of soil profile.The maximum depth of SOM δ¹³C in soil profile was different in origin and magnitude with the penetration depth of ¹⁴C produced by nuclear explosion in the atmosphere,indicating the controlling effects of topography and vegetation on the distribution of SOM carbon isotope with soil depth.

Changes of land use and landscape pattern in Taihu Lake Basin

WAN Rongrong, YANG Guishan

2005, 16(3):  475-480. 

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Based on three sets of land use data (1985,1995 and 2000),and by means of the techniques of remote sensing,geographical information system (GIS),and landscape ecology,this paper studied the changes of land use and landscape pattern from 1985 to 2000 in Taihu Lake Basin located at Yangtse River Delta.The results showed that in past 15 years,the farmland in this Basin decreased,while the built up areas,woodland,grassland and water body increased.The decrease of the farmland occupied 89.64% of total decrement,while the increase of the built up areas accounted for 79.21% of total increment.Under the disturbance of human activities,the landscape structure and landscape heterogeneity in Taihu Lake Basin changed greatly.The patches density decreased from 0.996 to 0.930,diversity indices decreased from 1.127 to 1.113,evenness indices decreased from 62.891% to 62.109%; while the edge density increased from 4.408 to 4.459,dominance indices increased from 0.665 to 0 679,and shape indices increased from 1.540 to 2.796.The landscape heterogeneity varied with different kinds of landscape,indicating the complexity of landscape ecosystem.In all kinds of landscapes,farmland and grassland had the highest values of diversity indices.The diversity indices of water bodies decreased firstly and then increased,while those of built up areas were in adverse.The evenness index was decreased in the order of woodland > farmland > grassland > water body > built up areas.Population,economy and policies were the driving forces of the dynamic changes of landscape pattern in Lake Taihu Basin during past 15 years,and land use change in the Basin caused distinct landscape effects,such as landscape fragmenting,edge effects intensification,and environmental quality declining.The mode of land use should be adjusted in landscape scale to rehabilitate and reconstruct the landscape ecosystems in Taihu Lake Basin.

Ditches protection in lake network based on landscape ecology

FAN Yingying, LIU Yong, GUO Huaicheng, MAO Guozhu

2005, 16(3):  481-485. 

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As a typical corridor landscape in lake network,ditch is an important component of lake ecosystem.In recent years,the ecosystem quality of Hanyang lake network in Wuhan City becomes worse and worse,mainly caused by the degradation of ditch corridor's function.In order to restore its function,this paper made an optimized design of the ditches' landscape pattern on the basis of landscape ecology theories such as corridor scale effect,heterogeneity,edge effect and ecological rehabilitation,and the analyses of ditches status.The contents were to control the water quality in the whole area in a larger scale,to dredge and rebuild the ditches to strengthen the corridor function,and to project the banks of ditches to enhance the anti disturbance ability.The study indicated that the theories of landscape ecology should be used reasonably in the ditches protection in lake networks.

Relationships between climate change and rice development and its yield formation:A simulation study

LIU Taoju, YIN Xinyou, QI Changhan, TANG Jianjun, CHEN Meiqiu

2005, 16(3):  486-490. 

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With the application of mechanistic model (RICAM 1.3,RIce growth Calendar Model),this paper simulated the rice development and its yield formation under different climatic conditions at multi locations of Asia.A three stage Beta model (3s Beta) was developed to predict the flowering stage of rice and to describe its three successive phases of photo thermal response, i.e.,basic vegetative phase,photoperiod sensitive phase,and post photoperiod sensitive phase.The 1980～1989 multi location data of Morioka (Japan,39°43'N),Nanchang (China,28°36'N) and Los Banos (Philippines,14°11'N) were used to verify the suitability of the model in studying eco system change.Comparisons of simulated results with observed data showed that this model could generally predict the eco physiological processes of rice,and performed very well over a wide range of environments.

An ecological model for predicting amylose content in rice grain

LI Weiguo, ZHU Yan, DAI Tingbo, CAO Weixing

2005, 16(3):  491-495. 

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By planting rice varieties Indica and Japonica under different ecological environments in China,Japan and Thailand,this study analyzed the relationships between the grain amylose content of test varieties and the environmental factors including latitude,altitude,temperature and solar radiation during grain filling period,established the factor driven equations for amylose accumulation in rice grain,and developed an ecological model for predicting rice grain amylose content.The model was validated by using the data of different years,sites and varieties,with the RMSE being 0.4% and 0.5% for the grain amylose content of Indica and Japonica,and 0.39% and 0 50% for their planting areas,respectively.The results indicated that the model was accurate and applicable.

Effects of elemental sulphur and dicyandiamide on mitigating NO₃^-N leaching loss from vegetable soil

ZHAO Yanwen, LIU Changzhen, HU Zhengyi, GAO Yimin, WANG Cairong, BI Dongmei

2005, 16(3):  496-500. 

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In a pot experiment with allium as test plant and NH₄HCO₃ as nitrogen source,this paper studied the effects of element sulphur(S⁰)and dicyandiamide (DCD) on mitigating the NO₃ - N leaching loss from soil and on soil inorganic nitrogen (NO₃ - N and NH₄⁺ N) content.The results showed that within the 12 weeks of the experiment,the cumulative leaching loss of soil NO₃^- N in treatments S⁰+DCD and S⁰ was 83%～86% and 83% lower,while that of soil NH₄⁺ N was 16 8～21.0 mg·pot^-1 and 20.4～25.0 mg·pot^-1 higher than CK,respectively,and the cumulative loss of soil (NH₄⁺+NO^3-) N was 60% lower.By the end of the experiment,soil inorganic nitrogen content in treatments S⁰ +DCD and S⁰ was 79.9%～85.4% and 74.9～82.6% higher than CK,respectively.The cumulative leaching loss of inorganic N in treatment S⁰ +DCD was 4.6%～14.4% and 15.4%～30.1% lower,and the soil inorganic nitrogen content by the end of the experiment was 6.1% and 16 8%～36 0% higher than that of treatments S⁰ and DCD,respectively.Similar results were obtained when S⁰ was replaced by Na₂S₂O₃,but not by Na₂SO 4.The fact that the application of S⁰ could obviously decrease the NO₃-N leaching loss from soil could be contributed to the inhibitory effects of S₂O₄^2- and S₄O₆^2- originated from S⁰ oxidation in soil on the nitrification of NH₄⁺ N.S⁰ could retard the decomposition of DCD due to the effect of its oxidized products S₂O₄^2- and S₄O₆^2-,and thus,extend the inhibitory effect of DCD on NH₄⁺ N nitrification.It is suggested that S⁰ combined with DCD could be used as an effective nitrification inhibitor to control the NO₃-N leaching loss from vegetable soils.

Foraging habitat selection of Otis tarda dybowskil during its breeding season

ZHAO Jiang, WAN Dongmei, WANG Haitao, GAO Wei

2005, 16(3):  501-504. 

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From April to July of 2000 and 2001,the authors studied the foraging habitat selection of Otis tarda dybowskil in the southeast Keerqin of Inner Mongolia by sampling method.The results showed that whether at burned or at non burned grassland,the foraging habitat of Otis tarda dybowski had the same feature in vegetation structure,the plant height was about 13 cm on average,with the highest of 30 cm,and there were abundant species of plants and insects with big density that the bird favored to eat.The bird more concerned with the abundance of plants at burned grassland,while that of insects at non burned grassland.

Field attraction effects of different trapping methods on Monochamus alternatus

WANG Sibao, LIU Yunpeng, FAN Meizhen, MIAO Xuexia, ZHAO Xieqiu, LI Zengzhi, SI Shengli, HUANG Yongping

2005, 16(3):  505-508. 

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A comparative study on the field attraction effects of different attractant,trap,lure and controlled releasing amount on Monochamus alternatus showed that four test attractants had a certain trapping ability to Monochamus alternatus,among which,MA2K05 was the strongest,with a mean capture efficiency of 26.3 individuals each trap and being attractive to other species of Loleoptera and Hemiptera; MA2K13 took the second place,with 21.3 individuals each trap; while MA2K11 was the weakest,with 13.8 individuals each trap.Among the three lures tested,lures C (60 ml plastic cup with 2 of 5 cm round holes on the cover) and B (20 ml specified controlled releasing plastic bottle) had a comparatively stronger effect,with a capture efficiency of 34.25 and 20 3 individuals each trap,respectively; while lure A (20 ml specified controlled releasing plastic bottle,the releasing amount being smaller than that of lure B) was the weakest,with 14.7 individuals each trap.Because the attractant volume of lure C was 1.5 times larger than that of lures B and A,and the attractant for lure C was appended every 3～5 d,while that for lures B and A could be used for more than a month with once appended,lure B was the best on the whole.As for the test traps,Xuanzhou trap was superior to imitated Japanese trap,with a trapping efficiency of 36.4 and 9.7 individuals each trap,respectively.The attractiveness of attractants was not significantly enhanced when the dosage was increased from 20 ml to 80 ml,but significantly improved when it was up to 120 ml.

Feeding behavior of Serangium japonicum (Coleoptera:Coccinellidae),a predator of Bemisia tabaci (Homoptera:Aleyrodidae)

YAO Songlin, REN Shunxiang, HUANG Zhen

2005, 16(3):  509-513. 

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Serangium japonicum is an important predator of whiteflies in China.In this study,the Bemisia tabaci attacking behavior of S.japonicum adults and larvae was observed by a videocassette recorder.The results showed that the predatory behavior of S.japonicum adults was characteristic with six events, i.e.,walking,feeding,clearing,resting,vibrating wings,and excreting.The starved larvae of S.japonicum was fond spending all times in feeding and walking on host eggs,with no time in resting or clearing throughout the process.The time included in feeding and walking was not significant different among different instars of S.japonicum.The handing time per egg decreased with S.japonicum larvae developed from instar I to Ⅳ,but differed little between instar Ⅲ and Ⅳ.The starved females of S.japonicum spent longer time on egg feeding,but less time on clearing,resting and walking than satiated females.The time for starved female to predate on B.tabaci nymphs and pupae increased as the host nymphs developed.

Effects of herbicides on diversity indices of cotton field arthropod community.

WANG Xiangyang, ZOU Yun ding, MENG Qinglei, ZHANG Bingwang

2005, 16(3):  514-518. 

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This paper studied the differences of the diversity,abundance and evenness of arthropod community and sub community in cotton field among treatments haloxyfor k (A),paraquat (B) and contrast (CK).The results showed that in the diversity of phytophagous sub community, t_A-CK =3.099 and t_B-CK =2.449 (t>t_0.05 =2.228),the difference being significant,and in the diversity of predatory sub community, t_A-B =2.260 and t_A-CK =2.377 (t>t_0.05 =2 228),the difference being also significant.In the arthropod community and sub community,no significant difference was found for A-CK,B-CK and A-B.The abundance of arthropod community t_A-CK =4.359,and that of phytophagous sub community t_A-CK =2.963,the effect being all significant (t>t_0.05 =2 228).No significant difference was found in the evenness of arthropod community and sub community for A B,A CK and B CK.The biodiversity had the same change trend for treatments haloxyfor R (A) paraquat (B) and contrast (CK).

Effects of nitrogen supply on nutritional quality and antioxidative enzyme activities of spinach

ZHANG Yingpeng, LIN Xianyong, ZHANG Yongsong

2005, 16(3):  519-523. 

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A hydroponic experiment was carried out to study the effects of nitrogen (N) supply on the nutritional quality and antioxidative enzyme activities of spinach.The results showed that when the N supply increased from 4 to 8 mmol稬^-1,the biomass of spinach and its leaf vitamin C (Vc) content increased significantly,but a further increase of the N supply induced an obvious decrease of Vc content.An increasing N supply increased the nitrate content in leaves.The soluble oxalate content in leaves decreased slightly with the N supply from 4 to 8 mmol稬^-1 N,but increased with a further increase of supplied N.Total oxalate content increased firstly,and then decreased with increasing N supply.SOD and POD activities increased with the N level up to 8 mmol稬^-1 N,but drastically decreased with increasing N levels.CAT activity decreased when N level elevated.MDA content decreased firstly and then increased with increasing N levels,while free proline content decreased with increasing N supply.All of these indicated that 8 mmol稬^-1 N was an appropriate N supply level for spinach to improve its biomass,nutritional quality,and resistance.

Effects of Bt corn straw decomposition on soil enzyme activities and soil fertility

WANG Jianwu, FENG Yuanjiao, LUO Shiming

2005, 16(3):  524-528. 

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An incubation test with the straws of Bt corn 34B24 and its non transgenic isogenic line 34B23,Bt corn Nongda 61,and non transgenic Nongda 3138 was conducted to study the potential effects of Bt corn straw decomposition on soil enzyme activities and soil fertility.No significant difference in soil protease and acid phosphatase activities was found between treatments 34B24 and 34B23; but on day 75 of incubation,soil dehydrogenase activity was significantly higher in treatment 34B24 than in treatment 34B23.The same was true for soil invertase activity on days 15,45,60 and 75.Soil urease activity in treatment 34B24 was significantly increased on day 30,but decreased on days 45 and 75.A significant difference in several soil enzyme activities was also observed between the treatments of two Bt corn hybrids and their conventional cultivars at some sampling days.After incubation for 90 days,the contents of soil available P and K were significantly lower in treatment 34B24 than in treatment 34B23.The differences mentioned above resulted from the composition of test corn straws,which may be affected by the Bt gene transformation process.In order to accurately assess the effects of Bt corn straw decomposition on soil ecosystem,a standard classification system of soil enzyme activities should be established for different soil types from different regions.

Effects of Alternaria azukiae on physiological metabolism and active oxygen eliminating enzyme activities of Trifolium repens

LI Zheng, LIU Dengyi, DING Jiahong, WANG Yupeng

2005, 16(3):  529-532. 

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A pot experiment was installed to study the effects of Alternaria azukiae inoculation on the cell membrane permeability,pigment and MDA contents,and activities of SOD,POD and CAT of Trifolium repens.The results showed that A.azukiae infection made T.repens leaf tissue increase its cell membrane permeability,electric conductivity,over oxidation and MDA content,but decrease its pigment content.The electric conductivity and MDA content were positively related with infection time,whereas the pigment content was negatively related with it.Due to the stimulation by A.azukiae,the over oxidation of cell membrane was intensified,which resulted in a large amount of active oxygen accumulated and beyond the defense ability,the active oxygen metabolism system was destroyed,and the balance of protective enzyme system was broken.After 12 days of A.azukiae inoculation,the activities of SOD and CAT decreased by 55.2% and 37.8%,respectively,while the POD activity increased by 1.6 times.

Effects of oxalate on acid phosphatase adsorption and its activity on soil colloids and minerals

ZHAO Zhenhua, HUANG Qiaoyun, JIANG Xin, WANG Daizhang, GAO Hongjian, LI Xueyuan

2005, 16(3):  533-538. 

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By a batch method,this paper studied the effects of different concentration and pH of oxalate,an important root exudate,on the adsorption of acid phosphatase and its activity on <2 μm colloids of yellow brown soil and latosol,and on minerals goethite and kaolinite.The results showed that the acid phosphatase adsorption by goethite was less affected by the concentration of oxalate; while the adsorbed amount of this enzyme by the other test colloids and kaolinite was sharply decreased with the increasing oxalate concentration (0～5 mmol·L^-1) first,and then gradually increased to the level equal to or less than the blank,which may be related to the coordination type of oxalate on soil colloids and minerals,and their surface charge change and dissolution.In the systems oxalate existed,the adsorbed amount of acid phosphatase by soil colloids and minerals decreased in order of goethiteyellow brown soil > kaolinite > latosol.The pH value for the maximum adsorption of acid phosphatase was between the IEP of the enzyme and the PZC of test colloids and minerals.After the enzyme was immobilized on colloids and minerals,the pH of its maximum specific activity had no change,or shifted to a higher value.

CH₄ and N₂O emission from a winter-time flooded paddy field in a hilly area of Southwest China

JIANG Changsheng, WANG Yuesi, ZHENG Xunhua, LI Jing, HUANG Yao, HAN Guangxuan, ZHANG Zhongjie, ZHU Bo

2005, 16(3):  539-544. 

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By the method of static opaque chamber/ modified gas chromatography,a one year field experiment was conducted to measure in situ the CH₄ and N₂O emission from a winter time flooded paddy field in a hilly area of Southwest China.Gas samples were taken simultaneously from rice involved and rice uninvolved plots.The results showed that during rice growth period,the CH₄ emission from the winter time flooded paddy field was higher than that from other paddy fields,but largely lower than many previous reports for the similar regions in Southwest China.The average flux of CH₄ emission from rice involved plots was 22.76±2.76 mg CH₄·m^-2 ·h^-1 during rice growth period,9.64±1.17 mg CH₄·m^-2 ·h^-1 per year,and 1.43±0.20 mg CH₄·m^-2 ·h^-1 during non rice growth season; while that from rice uninvolved plots was only 2.03±0.18 mg CH₄·m^-2 ·h^-1 per year,markedly lower than those from rice involved plots.During rice growth season,the mean emission rate of CH₄ and N₂O was 4.53±0.38 mg CH₄·m^-2 ·h^-1 and 32.01±5.02 μg N₂O·m^-2 ·h^-1 from rice uninvolved plots,but reached to 22.76±2.76 mg CH₄·m^-2 ·h^-1 and 73.04±5.03 μg N₂O·m^-2 ·h^-1 from rice involved plots,respectively.Rice involvement resulted in 302% increment of CH₄ and 128% increment of N₂O emission.There was a clear trade off between CH₄ and N₂O emission in paddy fields.Even with a span of 500 years,our calculation showed that in this winter time flooded paddy field,the GWP contributed by N₂O production was 7.9% of the CH₄ contribution,and thus,the greenhouse effect of N₂O production from this field was very small.

Responses of soybean to O₃,CO ₂ and their combination.

BAI Yueming, WANG Chunyi, WEN Min

2005, 16(3):  545-549. 

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With cultivar “Zhonghuang 14" as test crop,this paper studied the effects of CO₂ and/or O₃ on the growth and development of soybean (Glycine max L.)in an open top chamber.The results showed that an increasing CO₂ concentration could defer the leaf's O₃ injury,and relax the injury degree.After treated with CO₂ for 20 days,the stoma resistance and transpiration rate of soybean leaves had little difference with CK.Only when fumed with high concentration CO₂ and O₃,the stoma became closed,stoma resistance increased,and transpiration rate decreased obviously.Compared with ambient atmospheric CO₂ and O₃ (CK),doubled CO₂ significantly increased the dry matter accumulation and grain yield,reduced the coarse fat and raw protein contents of grain,but the harvest index had no obvious difference;while doubled O₃ decreased the dry matter accumulation,grain yield and harvest index of soybean,reduced the coarse fat content,but increased the raw protein content of grain.The interaction of doubled CO₂ and O₃ had no obvious effects on the dry matter accumulation,grain yield and harvest index of soybean,but reduced the grain raw protein content to a certain extent and increased the coarse fat content obviously.

Distribution,migration and purifying effect of cadmium in artificial Avicennia marina wetland system

CHEN Guikui, CHEN Guizhu

2005, 16(3):  550-554. 

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An artificial mangrove Avicennia marina wetland was set up in a greenhouse,and an irrigation experiment with synthetic wastewater was performed to research the behavior of cadmium in the artificial wetland system.The synthetic wastewater C₁ had the characteristics and strength similar to normal municipal sewage,while C₅ and C₁₀ had the nutrients and heavy metals as five and ten times as those in C₁,respectively.The control was of 15‰ salinity.All the test wastewater was quantitatively irrigated weakly for a year.The results showed that the cadmium in the synthetic wastewater discharged into the system was mainly stagnated in soil subsystem (87.67%～96.74%),and only a small portion (0.43%～3.23%) migrated into plants and litters.After a year trial,the Cd content in roots was more than that in stems and leaves.The artificial Avicennia marina wetland system did have a significant effect on purifying cadmium in synthetic wastewater,and the purification rate for C₁,C₅ and C₁₀ was 90.43%,97.17% and 97.06%,respectively.

A new precipitation distribution hydrological model and its application

ZHANG Shengtang, KANG Shaozhong, LIU Yin

2005, 16(3):  555-558. 

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In distribution hydrological models,precipitation is the key input data for analyzing and computing hydrological processes.Finding a way to produce distribution precipitation data is a hotspot in hydrological research.This paper presented the hypothesis that the distribution of precipitation on the earth surface is the result of the effects of atmosphere system and terrain.Moreover,the spatial distribution of natural precipitation is a group of concentric ovals on the flat earth surface,and has a definite centre with maximum precipitation not affected by terrain.Supporting by the hypothesis,this paper established a new precipitation distribution hydrological model which could simulate the spatial distribution of precipitation,and modified the terrain effect on precipitation through Newton interpolation.The position of the precipitation centre and its precipitation amount were simulated in first time,and thus,the model could have a practical value in basin storm analysis and real time runoff forecasting.The model was tested by the precipitation data of the Xichuan river basin in the Loess Plateau,which indicated that the model had a high precision.

Effects of UV-B radiation enhancement on DNA damage of three red-tide microalgae species

CAI Hengjiang, TANG Xuexi, ZHANG Peiyu

2005, 16(3):  559-562. 

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The ecotoxicological and biochemical study with Heterosigma akashiwo,Alexandrium tamarense and Skeletonema costatum showed that the test three species of red tide microalgae had different sensitivities to UV B radiation enhancement,and the order from high to low was Heterosigma akashiwo,Alexandrium tamarense and Skeletonema costatum.The DNA damage of algal cells increased with UV B radiation enhancement,being more notable in Heterosigma akashiwo than in Alexandrium tamarense and Skeletonema costatum,and in Alexandrium tamarense than in Skeletonema costatum.The DNA damage of Heterosigma akashiwo and Alexandrium tamarense could be significantly repaired (P<0.05) after 6 days of UV B radiation removal,and that of Skeletonema costatum could be significantly repaired (P<0.05) after 3 days,which illustrated that the DNA damage of three red tide microalgae species could not indicate the damaged degree of marine microalgae resulted from UV B radiation enhancement.

Bioavailability of cadmium in seawater to Paralichthys olivaceus

ZHAO Yuanfeng, L? Jingcai, WU Yichun, SONG Xiaoyang, LIU Changfa, WANG Fan, ZHAO Chong, ZHENG Wei

2005, 16(3):  563-567. 

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With exposure experiment,this paper studied the accumulation and elimination of cadmium (Cd) in the viscera,muscle and gill of Paralichthys olivaceus,and the effects of TOC concentration in seawater on the Cd accumulation.The results showed that when the exposure concentration of Cd was 0.5 mg稬^-1,its accumulation in test tissues increased with time,and reached equilibrium on the 10th day.The accumulation was in order of viscera (147.73 mg穔g^-1 DW) > gill (15.55 mg穔g^-1 DW) > muscle (4.578 mg穔g^-1 DW),which meant that viscera was the main place for Cd accumulation.Determinations after moving the fish into clear seawater on the 13th day of exposure showed that due to depuration,the Cd accumulation in test tissues decreased with time.On the 15th day after moving,the Cd elimination was in order of viscera (80.66%) > gill (73.66%) > muscle (56 84%),suggesting that the Cd accumulation in Paralichthys olivaceus could be reduced to meet safe food standard.The TOC concentration in seawater had a significant effect on Cd accumulation,i.e.,the accumulation of Cd decreased significantly with increasing TOC concentration,demonstrating that the TOC in seawater could decrease the bioavailability of cadmium.

Alien species invasion in Southern China and its countermeasures

FAN Jihui, JIANG Li, CHENG Genwei

2005, 16(3):  568-572. 

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Alien species invasion may cause serious ecological damage,resulting in ecological crisis and biodiversity comedown,and further menacing existing human environment.At present,the invasion of alien species has brought very serious damage to China's environment and society.The direct annual loss of its agro forestry industry accounts for 574 billion RMB.Taking the alien species in Southern China as an example,this paper analyzed the bio invasion approaches,mechanics and damages,and aiming at the characters of invaded area and concerned ecosystems and species,proposed several prevention measurements,i.e.,pay attention to the phenomena of bio invasion and to the basic researches on it; intensify the legislation and establish scientific strategies for introducing alien species; enforce the quarantine on invasive species and establish countrywide monitoring system on alien species; enhance people's defending consciousness; and strengthen international cooperation and collaboration.

Maintaining mechanism of species diversity of land plant communities

SHANG Wenyan, WU Gang, FU Xiao, LIU Yang

2005, 16(3):  573-578. 

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The maintaining mechanism of species diversity of land plant communities is a key and advancing edge in biodiversity study.Botanists and ecologists have presented many hypotheses and theories with controversies,and no general theory system was available.In this paper,the problem was reviewed mainly on two scales.The first was big spatial scale,aiming at the physical and natural factors that affect the species diversity,including histories and ages of plant communities,gradient changes such as latitude gradient,water gradient,altitude gradient and soil nutrients gradient,area effect,and isolation; and the second was concentrated on a special plant community,and mainly discussed the relationships of biodiversity with biotic factors (primary productivity,relationship between species,and gap dynamics) and abiotic factors (succession,disturbance and spatial heterogeneity,and human activity).

Farmland nitrogen loss and its control strategies from the view of water environment

JIN Jie, YANG Jingping

2005, 16(3):  579-582. 

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Nitrogen is a major factor in maintaining crop yield and getting better economic return,but its over and unreasonable use may cause severe environmental pollution.From the view of water environment,this paper discussed the current effects of farmland nitrogen (N) loss on water pollution,the passes and mechanisms of farmland nitrogen loss,and its control strategies.To reduce the N surface runoff and leaching,effective measures should be taken,which include cutting down the paths from the source to transportation,and taking integrated measures to control N pollution.The BMPs (Best Management Practices) methods for N control suitable to China's situation were discussed on the basis of nitrogen source pollution rate.

Phosphatase activities in rice planting meadow brown soil and their responses to fertilization

SHEN Jupei, CHEN Zhenhua, CHEN Lijun

2005, 16(3):  583-585. 

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This study is aimed to investigate the activities of phosphomonoesterase (acid,neutral,and alkaline),phosphodiesterase and phosphotriesterase in a rice planting meadow brown soil at the lower reach of Liao River,and their responses to different fertilization treatments.The results showed that there was no significant difference in soil total P and organic P contents among all treatments,but soil available P content was significantly higher in treatment OM than in other treatments.Soil acid and neutral phosphomonoesterase had a higher activity than alkaline phosphomonoesterase and phosphodiesterase,while phosphotriesterase had the lowest activity.No significant difference was found in phosphatase activities between different fertilization treatments.Soil acid phosphomonoesterase activity had a significant correlation with soil total P and available P contents,while soil phosphodiesterase activity significantly correlated with soil organic P content.

Effects of different light source and dark-adapted time on phototactic behavior of cotton bollworms (Helicoverpa armigera)

JING Xiangfeng, LUO Feng, ZHU Fen, HUANG Qiuying, LEI Chaoliang

2005, 16(3):  586-588. 

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In this paper,the phototactic behaviors of different emergence period Helicoverpa armigera were studied in a phototactic box.The results showed that under the five test wavelength lights,different emergence period female and male moths had no significant difference in their phototactic behaviors.The phototactic rate differed significantly when the dark adapted time was between 15 and 30 min,but had no significant difference among 30,45 and 60 min.No significant difference was also found in phototactic rate between dark adapted time 0 and 15 min under test wavelength lights except green one (500～565 nm).