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1.
不同季节卡拉麦里山盘羊生境选择分析   总被引:2,自引:0,他引:2  
采用样线法分析不同季节新疆卡拉麦里山盘羊戈壁亚种的生境选择。结果表明:春季,卡拉麦里山盘羊生境主要集中在海拔1 100 m以上、坡度30°~60°、与隐蔽物距离小于0.1 km、与水源地距离小于4.0 km、与居民点距离大于2.0 km以及中高隐蔽级(0.5~1.0)的区域。夏季,盘羊生境主要位于中上坡、与隐蔽物小于0.1 km、远离道路和居民点(大于2.0 km)、植被盖度小于0.1、隐蔽级高(0.9~1.0)的山坡。冬季,卡拉麦里山盘羊多选择距隐蔽物距离小于0.1 km、距离水源大于2.0 km、距离居民点大于2.0 km、食物丰富的山坡。不同季节卡拉麦里山盘羊生境变量特征值大于1的主成分累积贡献率分别达到了71.972%(春季)、71.782%(夏季)和73.613%(冬季),反映了不同季节生境因子特征。春季,盘羊生境因子主要受人为和自然因素的影响,其中海拔和人为干扰因子(与最近道路距离)是最重要的影响因子;夏季,盘羊生境的选择主要受海拔、植物种数和水源的影响;冬季,盘羊生境的选择主要受食物和人类活动的影响。  相似文献   

2.
2006年8月和12月,在新疆车尔臣河下游阿克塔孜牧场,对塔里木马鹿夏季和冬季生境的选择进行了研究。选择5类生态因子,并设置290个10 m×10 m样方。选择结果表明,塔里木马鹿喜欢胡杨和芦苇、植被覆盖度较大、水源距离较近和认为干扰距离>1 000 m的环境。其中,夏季多选择芦苇草甸,冬季选择胡杨林和柽柳灌丛。对生境特征的主成分分析显示,前3个主成分的累计贡献率夏季达到71.277%,冬季达到67.925%,可以反映塔里木马鹿的生境特征。同时表明,影响塔里木马鹿生境选择的主要因素依次为人为干扰、植被类型和距水源距离。  相似文献   

3.
云南省德宏州小麦条锈菌越夏调查初报   总被引:2,自引:0,他引:2  
小麦条锈菌越夏菌源量直接影响着小麦条锈病的发生与流行。为了明确云南省德宏州是否是小麦条锈病菌的越夏菌源地,2010年和2011年在德宏州芒市江东乡海拔1 600、1 700、1 800、1 900m和2 000m处设置了小麦条锈病菌源观察圃,对观测圃中小麦品种和周围落粒自生麦苗上条锈病的发病情况进行调查,实时记录各观察点的温湿度。结果表明:(1)海拔2 000m的菌源观察圃能观测到小麦条锈菌越夏和越冬的情况,越冬菌源量和春季条锈病的发病情况存在相互影响的关系;(2)海拔1 900m及以上的地区最高日平均温度和旬平均温度均低于22℃,为小麦条锈菌的越夏区域;1 600~1 900m的区域内其最高日平均温度在22℃至25℃之间,最高旬平均温度均大于20℃小于23℃,符合小麦条锈菌越夏的理论温度要求;并且海拔1 900m及以上地区的菌源观察圃中可观察到小麦条锈菌越夏。以上结论证实了云南省德宏州芒市是小麦条锈菌的越夏菌源地之一。  相似文献   

4.
针对内蒙古中部地区2005~2010年212次飞机人工增雨作业个例中的65架次作业条件及作业效果较好的个例,利用多种资料进行了飞机人工增雨概念模型的分析研究。结果表明:在河套气旋、蒙古低涡系统影响下,在天气系统的前部发展中的高层云和层积云云系中作业。云底高度在4-5月应低于2250m,6-10月低于1850m;云厚在2Km以上。在春季积分水汽要达到10mm以上,夏季达到25mm以上;700hpa温度露点差≤2。其雷达回波形态为大面积的片状、片絮状和片带状;回波面积在扫描范围的1/4以上;主体回波强度达到或超过25d Bz,主体回波顶高大于等于4-5km。  相似文献   

5.
为查明乌鲁木齐地区蜘蛛群落特征及其变化,2008年4月7月及9月中旬对该区6种不同生境蜘蛛群落特征进行了调查,共获得蜘蛛2195只,分别隶属于28科47属71种。在六种不同生境共有的优势类群为狼蛛科Lycosidae、跳蛛科Salticidae、园蛛科Araneidae和蟹蛛科Thomisidae等四科,占总捕获量的54.94%。常见类群为逍遥蛛科Philodromidae、球腹蛛科Theridiidae、狡蛛科Dolomedidae、妩蛛科Uloboridae、漏斗网蛛科Agelenidae、幽灵蛛科Pholcidae、皿网蛛科Linyphiidae等7科,占总捕获量的34.52%,其余7科为稀有类群,仅占总捕获量的4.54%。不同生境所获得蜘蛛个体数和类群数之间差异均为显著(P<0.05),其个体数顺序为自然榆林>草地>防护林>居民点>果园>菜地,类群数顺序为自然榆林>防护林>草地>果园>居民点>菜地。不同生境蜘蛛组成和数量分布在不同季节之间差异较大,个体数在不同季节之间差异均为显著(P<0.05),其顺序为夏季>春季>秋季。以上结果表明,乌鲁木齐地区蜘蛛资源比较丰富,生境类型影响蜘蛛群落分布格局,植被丰富度和人为干扰是影响蜘蛛群落的重要因素。  相似文献   

6.
为探究天山乌鲁木齐河源1号冰川(简称“乌源1号冰川”)积雪微生物群落特征及其与气候环境的关系,采集该区域2021年春季(4月)海拔3549 m处(TSX1)以及夏季(6月)海拔3770 m处(TSX2)和海拔3800 m处(TSX3)表层雪样,针对细菌16S rDNA V3-V4区、古菌16S rDNA V4-V5区和真菌ITS2区分别进行高通量测序,分析雪样中细菌、古菌和真菌的多样性。结果表明:(1)乌源1号冰川表层雪微生物多样性具有季节性差异,细菌多样性春季较高夏季较低,而真菌多样性则相反。(2)在物种组成上,细菌优势门为Proteobacteria(58.13%~89.10%)和Bacteroidetes(4.24%~40.74%),优势属为Flavobacterium(2.32%~33.64%)和Polaromonas(0.01%~24.72%);古菌优势门为Thaumarchaeota(38.10%~97.55%),其次为Nanoarchaeaeota(0%~61.90%)和Euryarchaeota(0%~2.82%);真菌优势门为Ascomycota(7.06%~88.4...  相似文献   

7.
黑河中游土地利用变化对生态系统服务的影响   总被引:7,自引:1,他引:6  
土地利用变化直接改变生态系统结构、功能和过程,是生态系统服务变化的重要驱动力之一。基于黑河中游2000年和2014年土地利用/覆被数据和相关地理信息数据,利用InVEST模型模拟了黑河中游2000年和2014年生境质量、土壤保持量、水源涵养和气体调节4种生态系统服务的价值及空间分布特征,并通过划分5 km×5 km的格网计算其与土地利用强度的Pearson相关系数,定量分析土地利用变化对生态系统服务的影响。结果表明:12014年,黑河中游生境质量一般,土壤保持总量6.92×10~8t,产水量3.93×10~8m~3,固碳4.55×10~7t;2从2000—2014年,生境质量、水源涵养和气体调节能力大幅下降,东南部表现最为显著,土壤保持功能基本稳定;3土地利用强度与土壤保持不存在显著相关性,与生境质量、水源涵养和气体调节服务均呈正相关关系,表明土地利用强度的增加在一定程度上有利于生态系统服务价值的提高。研究结果可为黑河中游生态系统管理提供借鉴。  相似文献   

8.
在天山西部根据生境特点设置90个1m×1m草本样方,研究了天山云杉林草本植物的物种多样性季节动态。结果表明:共调查到162种草本植物,隶属于34科、110属。草本植物多样性季节变化明显,生长季内物种数、Gleason丰富度指数、Simpson和Shannon-Wiener多样性指数均呈单峰型分布,即6、7月最高,4、9月最低。不同生境草本植物多样性变化明显,阴坡和林缘生境草本植物多样性最高,林冠干扰明显的生境中物种多样性最低。因此,草本植物多样性季节变化受微生境和人为干扰影响。  相似文献   

9.
以天山中部乌鲁木齐河流域为研究区,基于研究区DEN数据、二类森林资源调查数据及Landsat数据,运用3S(GIS、RS、GPS)技术,采用分布频率指数、生境综合指数定量分析流域尺度1989 ~2013年云杉林与地形因子(坡度、坡向、海拔)的关系,结果表明:1)云杉林分布面积大小与海拔服从韦伯函数分布,83%的云杉林分布在海拔2000 ~ 2600m,海拔2200~2400m是其最宜分布区;2)云杉林在坡向上的分布受生境综合指数制约,在生境综合指数最优(0.7 ~0.8)的阴坡分布58.93%的云杉林,在西北坡和东北坡分布30.25%云杉林,在生境综合指数最低(0.3 ~0.4)的阳坡则无云杉林分布;3)使用高斯函数可定量刻画云杉林在不同坡度上的分布状况,83%的云杉分布在坡度16°~45°之间,陡坡(26°~ 35°)云杉分布频率最大,达35%;4)云杉林海拔分布下限为1770m.上述研究明确并量化了天山云杉林分布规律及其与环境因子间的关系,为研究区森林调整与经营提供理论依据.  相似文献   

10.
正重庆市武隆区海拔800~1 500 m的高山地区,因特殊的立体气候条件,夏季冷凉,适宜多种蔬菜生长,为了丰富高山夏季蔬菜种类,调整种植结构,经过几年的摸索,高山黄瓜避雨栽培6—8月上市,病害少,可延长采收,又正值山下平坝区黄瓜收尾,价格好,效益高,每667 m~2产7 000~9 000 kg,是一项值得推广的高效栽培技术。一、品种选择  相似文献   

11.
Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.  相似文献   

12.
Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.  相似文献   

13.
The genera ofMicrogaster Latreille 1804 andHygroplitis Thomson 1895 from China are presented systematically in this paper. Thirty-two species ofMicrogaster and three species ofHygroplitis are known in China. Diagnosis, character variation, distribution and host of each species among the two genera are presented, including its host and distribution. Keys to the species ofMicrogaster andHygroplitis are given. http://www.phytoparasitica.org posting Dec. 19, 2006.  相似文献   

14.
Plant Viruses Transmitted by Whiteflies   总被引:18,自引:0,他引:18  
One-hundred and fourteen virus species are transmitted by whiteflies (family Aleyrodidae). Bemisia tabaci transmits 111 of these species while Trialeurodes vaporariorum and T. abutilonia transmit three species each. B. tabaci and T. vaporariorum are present in the European–Mediterranean region, though the former is restricted in its distribution. Of the whitefly-transmitted virus species, 90% belong to the Begomovirus genus, 6% to the Crinivirus genus and the remaining 4% are in the Closterovirus, Ipomovirus or Carlavirus genera. Other named, whitefly-transmitted viruses that have not yet been ranked as species are also documented. The names, abbreviations and synonyms of the whitefly-transmitted viruses are presented in tabulated form together with details of their whitefly vectors, natural hosts and distribution. Entries are also annotated with references. Whitefly-transmitted viruses affecting plants in the European–Mediterranean region have been highlighted in the text.  相似文献   

15.
Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.  相似文献   

16.
A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVYN strain and six to the PVYO strain. No PVYC was found. Two other isolates reacted serologically like PVYO, but were unable to elicit a hypersensitive response from the Nytbr gene and probably represent the PVYZ group. At the molecular level, these two isolates showed a combination of both PVYO and PVYN and could be recombinants of these strains. Another isolate reacted serologically like PVYO, but induced vein necrosis in tobacco, like PVYN-Wilga. Some PVYN isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVYNTN group. The PVYNTN, PVYN-Wilga and PVYZ groups probably represent pathotypes within strains PVYN and PVYO, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.  相似文献   

17.
The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed.  相似文献   

18.
In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population.  相似文献   

19.
Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.  相似文献   

20.
In 1975 many tumours were observed in plants ofBegonia Schwabenland grown in Aalsmeer. Submersion of the roots ofNicotiana megalosiphon seedlings in a homogenate of tumorous tissue, induced tumours after two weeks. Short periods of submergence yielded results similar to those obtained after longer periods. Tumour homogenates lost their infectivity after ten min at 50°C. Aphids transmitted the infectious agent.Treatment with propylene oxide did not inhibit infectivity completely. Filtration through a 450 nm filter removed the infectious agent.Tobacco tumor virus or a viroid could not be isolated. Cultures ofCorynebacterium fascians, isolated from tumours ofN. megalosiphon were highly infectious and induced tumours in healthyN. megalosiphon andBegonia. Tumorous tissue homogenates ofPelargonium zonale, Dahlia sp.,Gladiolus sp., andLilium sp. also caused tumours inN. megalosiphon, from whichC. fascians was isolated. It was not possible to produce tumours inN. megalosiphon with homogenates from roses with symptoms of bud proliferation.Samenvatting In 1975 werden vele tumoren waargenomen inBegonia Schwabenland op Aalsmeerse bedrijven (Fig. 1). De infectiositeit van tumorweefsel kon goed en snel worden vastgesteld door de wortels van zaailingen vanNicotiana megalosiphon in een homogenaat van tumorweefsel te dompelen. Tumoren ontstonden na twee weken, de eindbeoordeling geschiedde na een maand (Fig. 2). Ook verschillende andereNicotiana spp.,Melilotus officinalis (Fig. 3) enPisum odoratum (Fig. 4) werden aangetast.Bij de infectiositeitstoets gaven zeer korte dompeltijden even goede resultaten als langere (Tabel 1). Infectieus sap verloor zijn infectievermogen na 10 min verhitting bij 50°C. Bladluizen brachten de smetstof over. Propyleenoxide verminderde de infectiositeit wel, doch onderdrukte deze niet totaal. Bij filtratie door een 450 nm filter bleef het infectieuse agens op het filter achter. Het tumor-inducerende agens was ook aanwezig in die delen van planten met tumoren welke gezond leken en het ging voor een gering deel over met zaad (Tabel 2).Uit tumoren konden wij geen tabakstumorvirus of een viroïde isoleren. Culturen vanCorynebacterium fascians, geïsoleerd uit tumoren vanN. megalosiphon bleken zeer infectieus en veroorzaakten tumoren inN. megalosiphon enBegonia. Homogenaten van tumorweefsel vanPelargonium zonale, dahlia (Fig. 5), gladiool (Fig. 6) enLilium Mid Century Hybrid Enchantment (Fig. 7) veroorzaakten ook tumoren opN. megalosiphon, waaruitC. fascians werd geïsoleerd. Met sap van kroeskopzieke rozen konden wijN. megalosiphon niet besmetten.  相似文献   

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