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1.
近54 a来甘肃省河东地区气候时空变化特征   总被引:2,自引:1,他引:1  
用甘肃省河东及其周围地区近54 a来26个观测站气温、降水量资料,分析气温和降水的时空变化特征及其突变情况。结果表明:近54 a来甘肃河东地区气温呈明显的上升趋势,年平均气温倾向率为0.26 ℃/10 a,特别是20世纪90年代以来气温明显升高;空间分布上,年平均气温变化总体上呈增加趋势,以陇东高原中北部和陇中高原北部地区升温幅度最为明显;季节上气温均呈升高趋势,其中以冬季气温升高最为显著。近54 a来全区年平均降水量呈减少趋势,平均每10 a减少12.01 mm,其东南部地区减少的幅度高于西北部。此外,甘肃河东地区气温在1997年发生了由冷到暖的突变,而降水量突变不明显。进而讨论了气温升高和降水减少对该地区农业生产的影响。  相似文献   

2.
1960-2009年甘肃省极端气温的变化   总被引:2,自引:1,他引:1  
利用1960-2009年甘肃省26个气象站的气温资料,采用线性倾向估计法、反距离加权法、Mann-Kendall突变检测法,分析甘肃省50 a来极端气温事件的时空间变化。结果表明:甘肃省极端气温的年代变化趋势基本一致;年际变化极端高温呈增加(上升)趋势,极端低温呈减少(下降)趋势;在空间分布上大部分地区极端高温呈增加(上升)趋势,极端低温呈减少(下降)趋势,但空间差异明显。另外,甘肃省近50 a来极端气温指数发生了明显的突变(通过0.05的置信度检验)。  相似文献   

3.
河西走廊干旱区农业气候资源变化特征   总被引:6,自引:0,他引:6  
以1960~2005年河西走廊地区19个气象站46年的气候资料为基础,运用气候变化倾向率方法对该地区年及春、夏、秋、冬四季的光、热、水等主要农业气候资源要素进行诊断分析,并应用Mann-Kendall方法对主要农业气候资源要素的突变性进行了检测和分析。结果表明,近46年来,河西走廊区域内的气温呈平缓上升趋势,热量资源比较丰富,特别是平均最低气温增温幅度明显,冬季增温大于春、夏、秋季,但总体增温幅度低于我国平均增温水平,温度等热量资源在20世纪90年代中期同步发生突变。降水量变化比较平缓,呈略有增加的趋势,且季节性明显,夏季降水增加的贡献最大,与降水有密切关系的蒸发潜力自60年代起一直呈上升趋势,并在90年代中期发生突变,增速加快,降水蒸发差从70年代起呈缓慢下降趋势,不存在突变现象。太阳辐射与日照时数变化趋势一致,总体呈上升趋势,变化倾向率均为正值,从地域分布上看,北部及中部走廊绿洲区数值增加明显。河西走廊区域内总体的农业气候变化以"气温升高,降水略增、日照增加"为主要特点。文章最后简要分析讨论了农业气候资源的变化给河西走廊农业生产带来的主要影响。  相似文献   

4.
利用甘肃省27个测站,近46a年历年夏季(6-8月)平均地面月气温资料,采用EOF、REOF、子波分析、Mann-Kendal突变检验法等方法,分析了气温的空间分布特征、时间变化特点并对平均气温时间序列可能的突变点分别进行了检测.结果表明:1)甘肃省夏季平均气温异常的全区一致性是主要特点,也存在河东、河西气温异常的差异...  相似文献   

5.
利用1960-2010年甘肃35站夏季(6-8月)逐日观测资料,分析暴雨、干燥和异常温度事件的变化特征。结果表明:近51 a甘肃河西区暴雨基本稳定在0.1次/a左右,而河东区在20世纪70年代中期前为显著下降趋势,之后其变化趋势不显著。两区暴雨事件的强度变化均不显著,但在时间上分布比较分散,80年代中期之后暴雨事件发生的时段较之前提前了约2候;河东、河西区的严重干燥事件频次均在1991年发生突变,突变后的显著增加主要是受降水日数在同期突变后显著减少的影响;异常高、低温频次均在90年代中期发生突变,突变后异常高温频次显著增加,异常低温频次显著减少。  相似文献   

6.
近47年来京津冀地区降水的变化   总被引:2,自引:3,他引:2  
利用线性回归、突变分析和小波分析方法,分析了京津冀地区1960-2006年84个地面台站降水量的变化。结果表明:47年来京津冀降水量呈下降趋势,气候倾向率为15mm/10a。除夏季外,其余季节降水量均呈增加趋势。由于华北地区夏季降水量集中了全年降水量的60%至70%,所以夏季降水量的显著减少使得年平均降水量呈下降趋势;京津冀地区夏季降水量在1996年代初减少是一突变现象,其他季节降水量无突变现象;京津冀地区年降水量和四季降水量大致存在3个主要周期的变化。  相似文献   

7.
近58年河西走廊地区气温变化及突变分析   总被引:18,自引:4,他引:14  
根据河西走廊地区敦煌、瓜州、酒泉、张掖、武威及乌鞘岭6个地面气象站1951-2008年的逐月平均气温、月平均最高、月平均最低气温资料,运用线性拟合、滑动平均和Mann-Kendall方法进行趋势和突变分析。研究表明:近58年来河西走廊地区年平均气温、最高气温、最低气温均呈上升趋势,其中最低气温的增温趋势明显大于平均气温和最高气温的上升趋势。年平均气温和最高气温暖突变均出现在20世纪90年代中后期,最低气温暖突变出现在1994年,气温年较差呈减小趋势。就各季而言,冬季气温的递增率最大,暖突变出现在80年代中后期,早于其他各季,说明河西走廊地区的增暖首先是从冬季开始的。  相似文献   

8.
姚俊强  杨青  赵玲 《干旱区研究》2012,29(2):320-327
利用天山地区44个站1961-2009年水汽压数据,采用线性趋势估计、距平分析、Mann-Kendall趋势统计突变检验和功率谱等方法,分析天山地区近地面水汽变化及其与区域气候变化的关系。结果表明:天山地区近49 a来水汽总体呈增多趋势,年和四季水汽变化具有年际和年代际差异,最大增多趋势均出现在20世纪90年代中后期至21世纪初,最小值出现在70年代中后期和80年代中期,最大值出现在21世纪初。突变和周期分析得出,水汽年变化与西北地区气候变化趋势具有明显一致性。年降水变化与水汽相关最高,温度和青藏高原指数次之,其他因子相关一般。  相似文献   

9.
阜康绿洲环境变化的气候特征   总被引:2,自引:4,他引:2  
利用月气象资料,对过去近30 a阜康绿洲气候变化特征进行分析和比较,结果表明:阜康绿洲气温具有显著的增暖趋势,年平均气温增加约0.6 ℃,对年气温变暖贡献最大的是春冬两季,分别升高1.2 ℃和1.3 ℃;阜康绿洲变暖的主要特征是最低气温升高,最低平均气温增幅达0.7 ℃;在20世纪80年代中期之前,不论是年还是季节的日照时数均呈上升趋势,之后呈下降趋势,并且总体呈下降趋势;蒸发量呈明显的下降趋势,90年代比70年代蒸发量下降约537.9 mm,夏季是年蒸发量下降的主要季节;降水量呈明显的上升趋势,90年代比70年代降水增加约60.54 mm,春夏两季是年降水量增加的主要季节.  相似文献   

10.
根据河西地区14个气象站点1961-2015年的逐月气象观测资料,基于SPEI指数采用Mann-Kendall趋势检验法、反距离加权插值(IDW)等方法分析了近55年来河西地区年代际、四季干旱及空间变化特征,并探讨了ENSO 事件与该区干旱的关系。结果表明:在年代际变化上,自20世纪90年代以来河西地区干旱次数增多、干旱程度加重。季节时间变化上,河西地区春、夏、秋季均呈干旱化趋势,春季干旱化趋势最为突出,夏季次之,冬季略呈变湿趋势。空间变化上,整个河西地区春季均呈干旱化趋势,而且大部分地区的春旱趋势极为显著,其中春旱趋势最显著的地方是金塔;冬季整个研究区趋于湿润化。各季节干旱高频区分别集中在:春季在金塔、民勤地区,夏季在河西西北部,秋季在河西中东部及西部的安西—玉门一线,冬季在101°E以西的河西地区。河西地区秋季SPEI与SSTA指数的相关性最为显著,春季次之,夏季最弱。ENSO事件发生强度与河西地区SPEI影响因子的多项式拟合关系表明,ENSO事件强度对温度的影响高于降水;其中在ENSO暖事件(厄尔尼诺事件)发生年份,气温有明显的上升趋势;在ENSO冷事件(拉尼娜事件)发生年份,少数年份降水有所增加,对气温的影响较弱。  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.
Molecular diagnostic techniques have been developed to differentiate the Ascochyta pathogens that infect cool season food and feed legumes, as well as to improve the sensitivity of detecting latent infection in plant tissues. A seed sampling technique was developed to detect a 1% level of infection by Ascochyta rabiei in commercial chickpea seed. The Ascochyta pathogens were shown to be genetically diverse in countries where the pathogen and host have coexisted for a long time. However, where the pathogen was recently introduced, such as A. rabiei to Australia, the level of diversity remained relatively low, even as the pathogen spread to all chickpea-growing areas. Pathogenic variability of A. rabiei and Ascochyta pinodes pathogens in chickpea and field pea respectively, appears to be quantitative, where measures of disease severity were based on aggressiveness (quantitative level of infection) rather than on true qualitative virulence. In contrast, qualitative differences in pathogenicity in lentil and faba bean genotypes indicated the existence of pathotypes of Ascochyta lentis and Ascochyta fabae. Therefore, reports of pathotype discrimination based on quantitative differences in pathogenicity in a set of specific genotypes is questionable for several of the ascochyta-legume pathosystems such as A. rabiei and A. pinodes. This is not surprising since host resistance to these pathogens has been reported to be mainly quantitative, making it difficult for the pathogen to overcome specific resistance genes and form pathotypes. For robust pathogenicity assessment, there needs to be consistency in selection of differential host genotypes, screening conditions and disease evaluation techniques for each of the Ascochyta sp. in legume-growing countries throughout the world. Nevertheless, knowledge of pathotype diversity and aggressiveness within populations is important in the selection of resistant genotypes.  相似文献   

19.
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   

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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