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1.
本文对兰州北山集流造林的九年生柽柳属十个种的保存率及生长状况进行了研究分析，筛选出适于当地生长的优良种为中国柽柳、多枝柽柳、密花柽柳、刚毛柽柳、异花柽柳和甘蒙柽柳共六种，为造林地树种选择提供了科学依据。  相似文献   

2.
沙漠油田基地路生物防沙试验段林木生长状况   总被引：6，自引：3，他引：3  
对沙漠油田基地路生物防沙技术示范工程中不同立地条件下所种植的梭梭、柽柳、沙拐枣三类灌木的生长状况进行了调查，对盐水灌溉后各种立地类型的沙地土壤水盐状况进行了取样分析。研究结果表明：在塔中沙漠油田基地路生物防护体系建设的过程中，在沙丘和平沙地上应选用沙拐枣和梭梭，如种植柽柳则需采取适当的土壤保水措施（如在种植坑内加施草碳、固水剂、粘土等）。在含有下伏亚粘土层的沙地上应选用柽柳和梭梭，在丘间板结沙地上要想营造防护林，必需采取适当的技术措施，使土壤疏松（如深开沟、回填流沙等）。  相似文献   

3.
通过对头状沙拐枣、白梭梭苗木在春季不同沙地含水量试验地造林调查,和体内水分平衡状况的测定,建立了萌发率、成活率和株高生长量与沙地含水量关系的数学模型。指出头状沙拐枣造林的沙地含水量应保证在5.5%左右,白梭梭应保证在5.0%左右。  相似文献   

4.
戈壁人工梭梭林保存率及其生长状态一直是一个备受关注的问题,文中基于戈壁区野外调查和室内试验,分析了阿拉善左旗、右旗、额济纳旗沙砾质地不同树龄人工梭梭林的保存率及生长状态。结果表明：1)沙砾质戈壁人工梭梭林在左旗、右旗、额济纳旗平均保存率分别为76%,74%,38%。2)戈壁栽植梭梭在造林初期破坏砾石层,加速地表沙化,随着林龄增加,风沙对梭梭林地表干扰程度小,林下表层土壤组分相对稳定。3)戈壁区梭梭林造林成本高,左旗、右旗、额济纳旗3年平均造林成本分别为11169.41元/hm2、11641元/hm2、9832.29元/hm2。4)沙砾质地戈壁人工梭梭林与盐湖、沙地人工梭梭林相比生长表现差,同为2、3年林龄盐湖与沙地人工梭梭林株高-冠幅-基径特征与戈壁人工梭梭林相比,株高分别是戈壁人工梭梭林的1.9倍、2倍,基径是戈壁人工梭梭林的2.6倍、1.5倍;研究区内人工梭梭林生长表现差、保存率低、造成地表扰动、造林成本高、因此不建议在极端干旱地势平坦的沙砾质戈壁进行大面积造林。  相似文献   

5.
吐鲁番盆地是我国地势最低的地方,盆地最低点在海平面之下155 m,以高温、干燥、多大风而著称。全年大于八级的大风日为26.8 d,干热风、风沙灾害极为严重。营造防沙林带便成为防治风沙灾害的一种重要措施。吐鲁番市灌木防护林采用的造林模式有：1.片状灌木防风固沙林即在沙荒地成片造林,根据灌水方式有平地造林和开沟造林两种方式。平地造林是视地形围拦水坝,将坝内沙地大致推平后全面灌水,然后造林。  相似文献   

6.
通过对60 a来民勤西沙窝沙区生态植被观测研究,在地下水位持续下降过程中,植被演替主要经历了4个阶段：退化草甸、柽柳群系阶段;柽柳群系、白刺群系阶段;白刺群系、退化柽柳群系阶段及白刺群系阶段,是植物多样性持续降低、植被覆盖度显著下降、生态严重退化与沙漠化快速发展的过程;随着雨养面积不断扩大,降水量较大的年份,沙旱生草本植物增长,其物种多样性与植被覆盖度增加,降水量小的年份则反之;沙旱生灌木植被相对稳定,年降水量超过140 mm,促进灌木植物种群生长发育,100～140 mm维持生长,低于100 mm趋于退化;多数人工固沙造林树种已退化和衰亡,梭梭作为外来树种生态适应性强,已发展为民勤沙区最大的人工固沙林,造林密度大、干旱是梭梭林退化的主要原因,按植被承载量,低密度造林后可持续性增强;近年来,随着流域综合治理,统筹用水,民勤生态用水供给增加,局部区域地下水位有所上升,形成了一些微域性湿地,过去的草甸植被重现,生态正向发展,而多数沙区的地下水位下降也在减缓,荒漠化仍在发展。  相似文献   

7.
短毛柽柳(Tamarix karelinii)是分布于盐渍化沙地和重盐碱地的灌木。为了阐明短毛柽柳种子的萌发特性,设置不同的温周期、储藏时间和盐分梯度,采用室内控制实验研究这些因子对种子萌发的影响。结果表明:1短毛柽柳种子在4个温周期中均具有高的萌发率,并且温周期温度越高,种子的萌发速率越快。2室温贮藏1个月显著提高种子的萌发速率,在贮藏6个月内,种子的最终萌发率都能达到100%。3≤0.8 mol·L~(-1)的Na Cl溶液对种子的最终萌发率无显著影响,而≥1.0 mol·L~(-1)的溶液则抑制种子的萌发,且随着浓度的增加,种子的最终萌发率呈下降趋势,直至为0。将1.0~4.0 mol·L~(-1)溶液中没有萌发的种子,转移至蒸馏水继续培养后,仍有71.67%~28.00%的种子恢复萌发率,表明种子具有较强的耐盐性。对短毛柽柳种子萌发特性的研究,为短毛柽柳的种苗培育提供基础资料。  相似文献   

8.
文中通过对毛乌素沙地立地条件和经长期自然淘汰保留下来的树种生态适应性调查分析,将毛乌素沙地划分出7种立地类型,应用综合评价法对不同立地类型上的树种进行适宜性评价,为毛乌素沙地治沙造林树种选择与配置提供科学依据。评价结果为固定沙地上筛选出最优树种7种,适宜性由大到小分别为柠条、沙柳、杨柴、花棒、樟子松、沙棘、沙地柏,较适宜树种6种,适宜性由大到小为文冠果、油松、新疆杨、紫穗槐、杜松、小叶杨;半固定沙地最优树种4种,适宜性由大到小为杨柴、花棒、沙柳、沙棘,较适宜树种3种,适宜性由大到小为柠条、沙地柏、文冠果;流动沙地最优树种为杨柴、花棒,较适宜树种为沙柳;草滩地上最优种为旱柳,较适宜树种为沙棘、乌柳、箭杆杨、沙柳;盐碱滩地上最优种为柽柳,较适宜树种为沙棘、乌柳、旱柳;硬梁地上最优树种为沙棘、油松,较适宜树种为柠条、侧柏;软梁地上最优种为柠条、沙棘,较适宜树种为榆树、油松。  相似文献   

9.
沙地饲料灌木林营造技术研究   总被引：2，自引：0，他引：2  
沙地饲料灌木林营造技术研究白永强，王力（宁夏区林业研究所，银川，７５０００４）李得庆（青海省互助县哈拉直沟林业站）关键词沙地，饲料灌木，造林盐池沙地是本地重要的天然牧场，由于自然条件恶劣，生境脆弱，加之牲畜逐年增加，草原超载，过度放牧，使得草场退化，...  相似文献   

10.
土壤水分是沙地植被格局和过程改变的主要驱动力,也是干旱半干旱区植物生长最大的限制因子.沙漠地区的土壤水分表现出明显的空间异质性.以高寒半干旱沙地青海湖东沙地为研究区,以栽植人工固沙植物(小叶杨、樟子松、沙棘和乌柳)的沙丘和自然固定沙丘(沙蒿为优势种)作为研究样地,探讨不同固沙植物影响下的沙丘不同地貌部位土壤水分变化特征...  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.
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   

14.
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   

15.
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   

16.
《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   

17.
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   

18.
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   

19.
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   

20.
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   

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