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1.
采用资料收集和实地调查相结合的方法，系统分析了辽西地区人工林资源状况，明确了这一地区人工林资源的分布和结构特征以及存在的主要问题，为今后辽西林业的可持续发展提供依据。  相似文献   

2.
辽西地区相对资源承载力与可持续发展研究   总被引：3，自引：0，他引：3  
本文讨论并改进了相对资源承载力的概念、研究思路和计算方法,选择具有代表性的辽西地区,实证分析1988—2004年辽西地区相对土地资源承载力、相对经济资源承载力、相对生活水平承载力和综合承载力的演变和空间差异,预测2010年和2015年辽西地区的人口超载规模,分析辽西地区相对资源承载力存在问题的原因,提出辽西地区实现可持续发展的对策。  相似文献   

3.
甘肃小陇山日本落叶松人工林土壤优势真菌多样性探讨   总被引：1，自引：0，他引：1  
为了初步了解国家级自然保护区小陇山沙坝地区日本落叶松人工林夏季土壤真菌生态分布与多样性情况,利用全球卫星定位系统(GPS),在天水小陇山日本落叶松栽种区沙坝地区抽取10块日本落叶松人工林样地,采用稀释平板法对该地区日本落叶松人工林土壤真菌进行分离计数,结果表明该区土壤真菌数量较少。并分离鉴定出4个优势属,其中青霉属(Penicillium)和曲霉属(Aspergillum)是该地区最常见的类群。为了进一步了解该区日本落叶松人工林土壤质量与土壤真菌数量及多样性的反应机制,对该区日本落叶松人工林真菌区系又进行了多样性分析:不同采样区多样性指数波动较大,物种多样性较低,土壤真菌数量较少。  相似文献   

4.
为探明辽西地区设施蔬菜灰霉病菌抗药性发展现状,采集了172株灰霉病菌,对腐霉利、嘧霉胺、啶酰菌胺、氟啶胺进行抗性频率和抗药性水平检测。结果显示：辽西地区灰霉病菌对上述4种药剂的抗性频率分别为72.09%、87.79%、16.90%、2.32%;相应的EC50范围分别为0.175～7.147、0.003～107.823、0.172～74.329、0.001～2.678μg/mL。由此得出：嘧霉胺已不适合在辽西地区使用;腐霉利要严格使用次数,注意轮换用药;氟啶胺、啶酰菌胺抑菌活性较高,可作为主力防治药剂,但仍需科学使用。  相似文献   

5.
辽宁省循环经济发展水平区域差异分析   总被引：1，自引：0，他引：1  
循环经济是实现资源型城市经济转型、可持续发展的有效方式之一。科学评价循环经济发展水平对区域可持续发展及确定其未来发展方向有重要意义。根据国家统计局制定的循环经济评价指标体系和"3R"原则构建了辽宁省循环经济评价指标体系。运用模糊综合评判方法和GIS方法对辽宁省循环经济发展水平区域差异作了定量分析。结果表明:辽宁省14个地区循环经济发展水平差异显著,整体上沿海地区好于内陆地区;沈大沿线好于周边地区,并向东西两侧逐级递减;资源型城市水平普遍偏低;辽西半干旱地区水平最低。最后分析影响辽宁循环经济发展的主要因素,并提出循环经济发展建议。  相似文献   

6.
建平县位于辽西北地区，属大陆性半干旱气候，光照充足，土地资源丰富，适合梨树生长发育的要求，经多年的努力发展，该县已拥有梨树２８３３ｈｍ２，１２７万株，并取得了良好的经济效益。但是，由于近年来梨木虱的严重为害，经济损失严重，对梨树生产威胁较大。为此，建...  相似文献   

7.
辽西半干旱区秋后覆膜保墒对翌年春玉米生长发育的影响   总被引：2，自引：0，他引：2  
针对辽西半干旱地区春旱严重、降雨资源年内分布不均的气候特点,在秋收后、霜冻之前进行灭茬覆膜处理,试验对旱地雨水资源跨时间调节。翌年春季土壤含水量、玉米生长状况及产量的试验结果表明,秋覆膜处理的耕层土壤含水量比未覆膜处理高出60%,播种15d后玉米出苗率达到85%,抽穗期玉米株高比未覆膜处理高33cm、径粗增加0.42cm,秋收时玉米穗重比未覆膜处理提高了49.62%。研究表明,春墒秋保、跨时间调控农田水分状况是北方干旱半干旱地区有效的农业节水措施。  相似文献   

8.
采用RT-PCR对辽西地区采集的45份核果叶片样品进行了李属坏死环斑病毒(PNRSV)的鉴定,其中9份样品为阳性。以阳性样品总RNA为模板,克隆了PNRSV基因组RNA3近全长序列。序列长度在1 612~1 619 bp之间,一致性为93.8%~100%。以本研究获得的9个和Gen Bank登录的42个PNRSV近全长RNA3序列为基础,截取cp基因、mp基因和近全长RNA3序列分别构建系统发育树,三者结果一致:均可将51个PNRSV分离物分为4个组,即PV32、PV96、PE5和本文报道的一个新的PNRSV组,9个辽西分离物分别属于PV32组或PV96组。本研究明确了我国辽西地区PNRSV的遗传多样性,证明了PNRSV基因组RNA3在研究PNRSV遗传多样性中的适用性,同时发现了一个新的PNRSV组,对于PNRSV遗传多样性研究意义重大。  相似文献   

9.
基于Copula函数的辽西地区农业气象干旱灾害分析   总被引：1，自引：0，他引：1  
干旱作为辽西地区频发的自然灾害之一,对农业影响显著。综合考虑气象干旱灾害的多要素作用,本文基于SPI指数利用游程理论提取辽西地区1956—2014年农业气象干旱的历时和强度,在确定单变量边缘分布的基础上采用Copula函数分析干旱发生的联合概率和重现期,并以1991—2011年农作物旱灾实况为依据,探讨气象干旱重现期与作物旱灾损失之间的联系。结果显示:(1)干旱历时和干旱强度分别符合Weibull和Gev分布,Frank-Copula适合模拟辽西地区的干旱联合分布;(2)本区发生历时和强度双低、短历时-高强度、长历时-低强度干旱的可能性较大;(3)高强度-短历时和低强度-长历时组合下重现期多为2—4个月,辽西多轻、中旱;(4)1991—2011年旱灾实际重现期与理论重现期接近,表明联合重现期能更好地体现灾害发生频次;(5)重现期低于2个月为轻度干旱,2—8个月为中度干旱,高于8个月为重度干旱,农业部门可根据联合重现期预测出的干旱等级采取有针对性的防旱抗旱措施。  相似文献   

10.
亚寒带荒漠草原不同树种人工林土壤生态化学计量特征   总被引：1，自引：0，他引：1  
《干旱区研究》2021,38(5):1385-1392
为了阐明亚寒带荒漠草原不同树种人工林间土壤养分含量及生态化学计量特征的差异,通过野外调查与室内分析相结合的方法,在哈萨克斯坦首都努尔苏丹选取种植白桦、樟子松、梣叶槭3种不同树种,林龄为11 a的亚寒带荒漠草原人工林为研究对象,以裸地为对照,对其土壤养分含量及其生态化学计量特征进行了分析。结果表明:(1)土壤养分含量受树种的影响,但不同树种间生态化学计量特征差异不显著。(2)种植人工林后,不同树种人工林土壤有机碳与全氮含量均显著增加,针叶林与阔叶林土壤表层有机C、全N含量差异显著。(3)土壤C、N、P含量呈极显著正相关关系,C含量是C:N、C:P的控制因子,N含量是N:P的控制因子。研究区种植人工林后,虽然土壤养分含量显著增加,但是总体含量仍小于全球平均水平,当地土壤养分仍处于匮乏状态。N是该地区养分循环和植物生长的限制性因素,在人工林生长过程中适当施用氮肥,可加快人工林生长和生态恢复进程。本研究可为哈萨克斯坦首都努尔苏丹的人工林建设和持续经营管理提供科学依据。  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.
We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.  相似文献   

13.
《干旱区科学》2014,(6):782-782
正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad  相似文献   

14.
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   

15.
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   

16.
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   

17.
Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.  相似文献   

18.
Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F 3, F 4 and F 5, but not in F 1 and F 2 that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F 1 and F 2 in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.  相似文献   

19.
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20.
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   

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