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1.
黄土高原的土壤水分利用与生态环境的关系   总被引:12,自引:0,他引:12  
黄土高原的土壤水分利用与生态环境的关系韩仕峰,黄旭(中国科学院西北水土保持研究所,陕西杨陵712100)(水利部西北水土保持研究所,陕西杨陵712100)RelationshipBetweenSoilWaterUtilizationandEcologicalEnvironmentintheLoessPlateau¥HanShifeng;HuangXu(NorthwesternInstituteofSoilandWaterConsereation,AcademiaSinica,Yangling,ShaanxiProvince712100).ChineseJournalofEcology,1993,12(1):25-28。It'sconsideredbytheauthorsthattherearethreekindsofproblemsinutilizationofsoilwaterresourcesintheLoessPlateau:1.formationofadefinitethicknessofdrysoillayerduetointensivewaterabsorp-tionandconsumption  相似文献   

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黄土丘陵区柠条林地养分状况及其循环规律   总被引:16,自引:1,他引:15  
黄土丘陵区柠条林地养分状况及其循环规律刘增文李雅素(西北林学院,陕西省杨陵712100)FertilityandElementsBio-CyclingsoftheCaraganaMicrophylaL.ForestlandintheRolingLoe...  相似文献   

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农业气象灾害地域组合规律的初步研究   总被引:1,自引:0,他引:1  
农业气象灾害地域组合规律的初步研究石忆邵(西北农业大学经贸学院,陕西杨陵712100)PreliminaryStudyonAreaCombinationLawofAgro-MeteorologicalDisasters¥,ShiYishao(Nort...  相似文献   

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检测大麦抗BYDV的蚜虫获毒的酶联免疫吸附法   总被引:1,自引:0,他引:1  
检测大麦抗BYDV的蚜虫获毒的酶联免疫吸附法刘常宏(陕西省植物保护研究所,陕西杨陵712100)S.Haber(AgricultureCanada,WinnipegResearchStation,Canada)关键词酶联免疫吸附法,大麦,大麦黄矮病毒...  相似文献   

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黄土高原适生树种苗木的耗水特性   总被引:40,自引:3,他引:37  
黄土高原适生树种苗木的耗水特性韩蕊莲,梁宗锁,侯庆春,邹厚远(中国科学院西北水土保持研究所,杨陵712100)WaterconsumptionpropertiesofadaptablenurserystocksonLoessplateau¥HanRu...  相似文献   

6.
道路农田防护林系统水分关系研究   总被引:4,自引:0,他引:4  
道路农田防护林系统水分关系研究任勇,王佑民(北京林业大学,100083)(西北林学院,陕西杨陵712100)WatcrRelationsinFarmlandShelterbeltSystembytheRoads.RenYong¥(BeijinigForeslryUziuersity,100083),WangYoumin(NorthwesternCollegeofForestry,Yangling,Shaanxi,712100).ChineseJournalofEcology,1993,12(4):l-6.IntheregionfromloessplateautoNorthWeiRiver,20-100cmsoillaveristhemainlaverfromwhichtherootsystemofP.×dakuanensisHsuabsorbswater,and0-0.1HistherangeinwhichP.×dakua-nensisbytheroadsstronglyaffdctsbytheroadsstronglyaffectsmoistureconditionoffarmland.Theannual  相似文献   

7.
非持久性病毒传播机制的研究进展   总被引:3,自引:1,他引:2  
非持久性病毒传播机制的研究进展吴云峰(西北农业大学植物保护系,陕西杨陵712100)周广和(中国农业科学院植物保护研究所,北京100094)AdvancesinTransmissionMechanismofNonpersistentVirusesby...  相似文献   

8.
生态系统稳定性研究的历史与现状   总被引:27,自引:2,他引:25  
生态系统稳定性研究的历史与现状刘增文李雅素(西北林学院,陕西杨陵712100)HistoryandStatusofResearchofEcosystemStability.LiuZengwen,LiYasu(NorthwesternColegeofF...  相似文献   

9.
温度对麦长管蚜的影响   总被引:6,自引:0,他引:6  
温度对麦长管蚜的影响汪世泽,郝树广(西北农业大学陕西杨陵712100)EffectsofTemperatureonEnglishGrainAphid¥.WangShize;HaoShuguang(NorthwesternAgriculturalUniversity,Yangling,ShaanxiProvince712100).ChineseJournalofEcology,1993,12(3):53-56.InanexperimentalpopulationofEnglishgrainaphid,thedevelopmentrateV(t)ofalataeislowerthanthatofapterae,andtheV(t)of4thinstarofalataeistheIowest.Thealataeappearstobeabletotoler-ateawiderrangeoftemperature,butthesurvivalcurveisaffectedevidentlybyit.Atlowtemperature,thecurvedeclinesslowly,butathightemperature  相似文献   

10.
非致病微生物在植物—病原菌协同进化中的作用   总被引:2,自引:0,他引:2  
非致病微生物在植物-病原菌协同进化中的作用单卫星(西北农业大学植保系,陕西杨陵712100)TheRoleofNon-pathogenicMicroorganismsinPlant-pathogenCoevolution¥ShanWeixing(Depart-mentofPlantProtection,NorthwesternAgriculturalUniversity,Yangling,Shaanxi712100).ChineseJournalofEcology,1993,12(6),54-59.Inviewofpresentproblemsassociatedwithplantdiseasecontrol,coupledwithrecentadvancesinbiolog-icalcontrolofplantdiseasesandplant-pathogeninteractions,theauthorpointedouttheimportanceofnon-pathogenicmicroorganismsinhabitingplantsurfacesinregulationofplant-pathoge  相似文献   

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It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.  相似文献   

16.
Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

17.
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

18.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细  相似文献   

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For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.  相似文献   

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