Identification of a phytoplasma associated with pomegranate little leaf disease in Iran     

《Crop Protection》2016

During 2012–2014 surveys for the presence of phytoplasma diseases in Fars province (Iran), pomegranate little leaf symptoms were observed in several orchards in Khafr and Neyriz areas. Samples collected from symptomatic plants positively reacted in nested PCR assays using P1/P7 followed by R16F2n/R16R2 primer pairs producing the expected 1,250 bp DNA fragments. Real and virtual RFLP analysis showed that the sequences of phytoplasma strains from Khafr and Neyriz (KPLL and NPLL strains, respectively) were identical to each other and belong to 16SrII phytoplasma group, subgroup D. Phylogenetic analysis of the R16F2n⁄R16R2 DNA region confirmed that KPLL and NPLL phytoplasmas were enclosed in the same clade as other 16SrII-D subgroup phytoplasmas. This is the first reported occurrence of a 16SrII phytoplasma infecting pomegranate trees.  相似文献   

小灵猫繁育技术的研究   总被引：1，自引：0，他引：1  

钱伟平 《经济动物学报》1999,3(1):45-50

小灵猫的繁育技术尚未成功，尤其是仔猫哺育中母猫食仔的难题没有解决。在１９８６～１９９５年，我们对小灵猫的发情、配种、妊娠、产仔、母猫哺育和仔猫的人工哺乳作了试验。在此基础上形成了一套技术方案，并且在仔猫哺育上取得了突破性进展。  相似文献   

小灵猫泌香规律试验研究   总被引：2，自引：0，他引：2  

钱伟平 《经济动物学报》2000,4(3):35-40

对连续 7年的小灵猫产香记录进行统计分析 ,就二因子差异和相关关系进行显著性检验 ,结果显示 ,小灵猫的年度泌香周期中存在一个高峰期 ,与小灵猫的繁殖季节相对应。小灵猫的泌香和挤香之间 ,每一月度的首次挤香和第 2次挤香之间存在着显著的相关关系。小灵猫的泌香不存在性别差异。此外 ,饲料和营养的改善能提高产香量。  相似文献   

Geomorphological significance of lichen colonization in a present snow hollow: Hoya del Cuchillar de las Navajas, Sierra de Gredos (Spain)     

Leopoldo G. Sancho  David Palacios  Javier de Marcos  Fernando Valladares 《CATENA》2001,43(4):137

This paper discusses the results of a lichenometrical and geomorphological study of one of the few remaining active snow hollows in the central region of the Iberian Peninsula. The study area, located on a glacial shoulder, is called Hoya del Cuchillar de las Navajas. A protalus rampart occurs at the base of the hollow. Our studies, conducted between 1992 and 1998, were designed to determine the geomorphological characteristics of Hoya, the mobility of the deposits, and the characteristics of the snow cover. These data formed the basis for a study of the lichen colonization on the blocks and on the wall surrounding the snow hollow. All of the lichen species found were analyzed according to their abundance, distribution and the extent of their surface cover. Measurements of the diameter of the thalli of the species Rhizocarpon geographicum were also obtained. Thalli of this species were found to require a mean snow-free growing season of at least 95 days (13.5 weeks) per year. Maximum mean thallus diameters indicate that the protalus rampart was formed during the Little Ice Age and became inactive 130 years ago.  相似文献   

硫酸盐对小白鼠钼代谢的影响     

杨自军  龙塔  冉林武  王婷  温文彦  白东英  林霖  李玉法 《河南科技大学学报(农学版)》2004,24(4):31-33

实验选择健康小白鼠52只,体重(20±0.8)g,适应5d后,随机分为4组,每组13只,实验56d。定期剖杀检查,结果表明:I和II组小白鼠有轻度中毒表现,II组与III组RBC差异显者(P<0.05),HB呈下降趋势,组间比较差异均不显著(P>0.05),II组与III组WBC差异显著(P<0.05),I组ANAE+阳性率略高于IV组,II组ANAE+阳性率持续下降,6周后与I组差异显著(P<0.05),硫与钼存在剂量效应关系。  相似文献   

遮光对小棚漂浮育苗的影响     

代飞  张昆  段凯  邓道茂  王修林 《安徽农业科学》2007,35(33):10741-10742

[目的]有效解决小棚漂浮育苗不易成功的问题。[方法]用松枝(杉枝)、遮阳网、草扇进行遮光,于2002~2004年研究了遮光对小棚漂浮育苗的影响。[结果]随着遮光程度的增加,出苗率呈逐渐上升趋势,在遮光度达25.0%,出苗率接近100%,再增加遮光程度,出苗率稳定在90%以上。遮光度在20.0%~30.0%时,烟苗素质好,随着遮光程度增加,烟苗素质逐渐减弱。遮光时间从播种至小十字期比较适宜,遮光的最关键时期是刚开始出苗时。湿松枝(杉枝)遮盖棚面对烟苗出苗率效果最好,其次为遮阳网>草扇>对照。遮光能稳定小棚内温度,4种遮光方式的效果为草扇>松枝(杉枝)>遮阳网>未遮光(对照)。遮光还能有效减轻自然灾害对烟苗的伤害。[结论]透光率70.0%~80.0%的遮阳网对小棚漂浮育苗的效果最好。  相似文献   

区域绿色小杂粮产地土壤质量评价——以山西省长治市为例     

付丽霞  马国华  白中科  赵亭 《山西农业大学学报(自然科学版)》2004,24(4):330-334

长治市13个县(市)的杂粮产地土壤质量监测和评价结果表明:产地92个样点的综合污染指数均小于0 7,污染等级属安全级,污染水平属清洁水平。土壤有机质含量>15g/kg(Ⅰ级)的占52 17%;10～15g/kg(Ⅱ级)的占33 70%;<10g/kg(Ⅲ级)的占14 13%。土壤全氮含量>1 0g/kg(Ⅰ级)的占32 61%;0 8～1 0g/kg(Ⅱ级)的占28 26%;<0 8g/kg(Ⅲ级)的占39 13%。土壤有效磷含量>10mg/kg(Ⅰ级)的占26 09%;5～10mg/kg(Ⅱ级)的占32 61%;<5mg/kg(Ⅲ级)的占41 30%。土壤有效钾含量>120mg/kg(Ⅰ级)的占91 30%;80～120mg/kg(Ⅱ级)的占7 61%;<80mg/kg(Ⅲ级)的占1 09%。土壤质量整体状况良好,适宜发展A级绿色食品。  相似文献   

野生小灵猫捕获初期对环境适应能力的观察   总被引：1，自引：0，他引：1  

钱伟平 《经济动物学报》1997,1(3):50-55

本文采用观察、统计的方法 ,收集了捕获初期的小灵猫在采食、运动、生长发育、繁殖率及对外伤和疾病的抵抗力等方面的数据和行为特征。分析出外界因子对小灵猫适应性的影响 ,总结出遮光、安静和引诱进食对捕捉初期小灵猫驯化的重要性 ,形成了一套有利于在生产实践中加强小灵猫驯化和适应的实际方法  相似文献   

TRMM/GPM和Stage IV降水产品在小流域水文模拟效用评估     

冯克鹏  田军仓  洪阳  唐国强  阚光远  罗翔宇 《排灌机械工程学报》2021,39(4):397-403

以地面观测降水作为参照,在美国俄克拉荷马州Little Washita River流域,对比分析了TRMM 3B42 V7,GPM-IMERG卫星降水和Stage IV雷达降水的精度,并用这3种降水产品驱动CREST分布式水文模型,评估了其水文模拟效用.研究表明:3种降水产品与地面降水的相关系数均大于0.5,通过了0.05置信水平检验;GPM-IMERG和TRMM3B42 V7卫星降水对无雨和微雨存在低估,对大雨和暴雨存在高估;总体上,Stage IV降水精度最好,其次GPM降水精度优于TRMM 3B42 V7.在水文模拟效用评估中,设定相同率定期,分别使用3种降水产品率定CREST模型参数,得到率定参数集后,在相同验证期对流域日径流过程进行模拟.对比结果表明:Stage IV雷达降水在小流域水文模拟中效果最好,GPM-IMERG次之,TRMM 3B42 V7模拟效果不理想.  相似文献   

Insights into the genetic diversity and evolution of Little cherry virus 1          下载免费PDF全文

A. T. Katsiani  V. I. Maliogka  G. D. Amoutzias  K. E. Efthimiou  N. I. Katis 《Plant pathology》2015,64(4):817-824

Little cherry virus 1 (LChV‐1), a member of the recently proposed genus Velarivirus, is a sweet cherry pathogen that has been recently reported to infect other Prunus species and is associated with various plant disorders. In this work the incidence of the virus on its putative hosts and possible mechanisms driving its evolution were investigated. Due to problems encountered with LChV‐1 detection, a new nested RT‐PCR assay was developed and applied. The virus was found to be prevalent in cherry plantations in Greece and only occasionally detected in other Prunus species. Sequences corresponding to the partial RNA‐dependent RNA polymerase (RdRp), heat‐shock protein homologue (HSP70h) and coat protein (CP) genes were determined from Greek LChV‐1 isolates originating from different hosts; these were analysed, along with published homologous genomic regions from other isolates. Phylogenetic analysis of the three genes revealed the segregation of four evolutionary distinct groups showing no host or geography‐based clustering. Mean genetic distances among the four groups were high with the CP region showing the highest divergence, although intragroup variability levels were low. Nevertheless, estimations of the mean ratio of nonsynonymous substitutions per synonymous site to synonymous substitutions per synonymous site (dN/dS) for the partial RdRp, HSP70h and CP indicated that these genomic regions are under negative selection pressure. Interestingly, a recombination event was identified at the 3′ end of RdRp on a Greek virus isolate, thus highlighting the role of this mechanism in the evolutionary history of LChV‐1.  相似文献