毒麦(Lolium temulentum L.)

毒麦学名：Lolium temulentum L．；英文俗名：Poison Ryegrass，Bearded Ryegrass，Darnel；属单子叶植物纲(Monocotyledoneae)莎草目(Cyperales)禾本科(Poaceae)黑麦草属(Lolium L．)。俗名黑麦子、迷糊、小尾巴麦子。     

毒麦种子内生真菌Gloeotinia temulenta ITS序列分析

从国内采集了毒麦种子进行毒麦内生真菌Gloeotiniatemulenta的分离培养,没有能够成功分离到毒麦内生真菌的菌株,苯胺蓝染色镜检观察毒麦种子内的内生真菌带菌率为0~65.4%。直接从毒麦种子中挑取内生真菌菌丝,用基因释放剂(genereleaser,BioVenture)处理后扩增测序获得了毒麦内生真菌的ITS序列(DQ235697),经过相似性比对和分析,所得序列和GenBank中的内生真菌的序列同源性高达99.4%~100%,排除了毒麦种子表面真菌和毒麦种子序列的可能性。     

Development of microsatellite markers and their effectiveness in Lolium temulentum

Screening a genomic library of Lolium temulentum (darnel) with synthetic (GT)₁₅ and (GA)₁₅ oligonucleotides, we identified microsatellite‐containing clones. Based on the sequence data of the clones, specific primer pairs were synthesized and their effectiveness examined using 10 L. temulentum and two L. persicum accessions from Asia, Africa and Europe. Fifteen primer pairs amplified single fragments, and five of them showed polymorphism in polyacrylamide gel electrophoresis in the L. temulentum and L. persicum accessions. Fifteen primer pairs reported in L. perenne (perennial ryegrass) were also applied in this study. Nine of them amplified the microsatellite alleles, and two of the nine showed polymorphic alleles in L. temulentum and L. persicum. For the polymorphic markers, polymorphic information content values ranged from 0.60 to 0.86 with an average of 0.76 among 10 L. temulentum accessions. The microsatellite markers developed for L. temulentum and L. perenne should be informative and powerful in analysing the intraspecific genetic diversity and the phylogenetic relationships of L. temulentum and L. persicum.     

Analysis of Lolium temulentum geographical differentiation by microsatellite and AFLP markers

The genetic diversity and relationships of 48 Lolium temulentum accessions derived from eight countries (Morocco, Egypt, Tunisia, Italy, Ethiopia, Pakistan, Nepal and Japan) were analysed using seven microsatellite and 44 AFLP polymorphic loci to investigate the origin and distribution of genetic variation. Cluster analysis was performed using the unweighted pair-group method with arithmetic averages (UPGMA) based on the simple matching coefficient of similarity. Nei's gene diversity (h) and the coefficient of gene differentiation (G_st) were calculated. The results from microsatellite analysis indicated that accessions from the same country did not always cluster together, probably because of the limited number of loci used. In contrast, AFLP clearly separated clusters between countries and/or regions; Pakistan–Nepal complex, the Mediterranean region, Ethiopia and Japan. The h value was much higher for microsatellite than for AFLP analysis, indicating that microsatellites are the more variable markers. For AFLP analyses, h values were highest in accessions from Pakistan–Nepal complex, and from the Mediterranean region. These are in agreement with proposals that the origin of L. temulentum lies between the South-western Asia and the Mediterranean basin. The clear groupings of accessions from each country and/or region with high G_st (0.688) indicate that exchange of seeds between them is limited.     

Awn of darnel (Lolium temulentum L.) as an anthropogenic dispersal organ: A case study in Malo, south-western Ethiopia

Darnel ( Lolium temulentum ), a weed of wheat and barley, is either awned or awnless. The role of the darnel awn in dispersal was investigated in relation to human's agricultural practices in cereal cultivation in a Malo village, Gaytsa, south-western Ethiopia. In 24 free-threshing wheat fields and 11 emmer wheat fields, 129 and 88 spikes (one spike per plant), respectively, of darnel were randomly sampled. At the market in Gaytsa, 11 free-threshing wheat grain samples and eight emmer wheat grain samples of 150–200 g were collected. For each grain sample, the number of wheat grains and awned and awnless grains of darnel were recorded. The relative percentage of the awned form in free-threshing wheat fields was 8.53% and that in emmer wheat fields was 70.45%. The relative percentage of awned grains in free-threshing wheat grains from the market collection was 3.55% and that in emmer wheat grain lots was 75.20%. The morphology of awned darnel grains resembles emmer wheat grains and awnless darnel grains resemble free-threshing wheat grains. Thus, grain mimicry controls the close association of the two forms of darnel with the wheat species. The lack of an awn itself functions for darnel grain as a dispersal mechanism in free-threshing wheat cultivation systems compared with other wild grass species.     

扶桑绵粉蚧及其近似种的形态鉴定

扶桑绵粉蚧是一种重要的外来入侵害虫,其分布广、寄主植物多,虫体小,发生危害隐蔽,并与其近似种混合交叉发生危害,野外识别鉴定困难,易暴发成灾,难于防控。本文通过野外调查,采集到多个扶桑绵粉蚧及其近似种石蒜绵粉蚧和双条拂粉蚧。通过制作玻片标本,分别从触角、眼、口器、足、腹脐、刺孔群、盘孔、管腺和体毛等部位比较了3种粉蚧的玻片显微特征以及野外活虫虫体特征,为检疫工作人员快速识别该虫及其近似种提供参考。     

进口木材中碎木长蠹属3个近似种的鉴别

2009年3月,深圳出入境检验检疫局从进口非洲多哥的原木中检出在我国未有分布记载的林木重要害虫--棋盘碎木长蠹[Xyloperthlla scutula(Lesne)].本文介绍了近年从进口原木、板材中截获的3种碎木长蠹:多毛碎木长蠹[X.crinitarsis(Imhoff)]、脂松碎木长蠹[X.picea(Olivier)]和棋盘碎木长蠹,分别介绍了雌雄成虫的形态特征,并列出了这3个近似种的鉴别特征检索表.     

弯孢类炭疽菌rDNA ITS区的RFLP分析及分类研究

 应用核糖体DNA ITS区的RFLP分析对3 8个不同寄主来源的弯孢类炭疽菌菌株的遗传多样性和系统发育进行研究。结果表明:弯孢类炭疽菌的ITS扩增区(ITS₄~ITS₅)约为650 bp,无长度变异。5种内切酶(Alu I、Bsu RI、Hin 6 I、Hpa Ⅱ和Taq I)的酶切图谱在种内是相似或一致的,而种间差异较大。ITS-RFLP共迁带UPGMA聚类分析的结果表明:3 8个弯孢类炭疽菌菌株被聚为6个类群,群与群之间分界明显,表明种的分界相当明显。ITS-RFLP分析的结果还揭示了一些近似种的分类关系,如,按传统方法分别鉴定为Colletotrichum truncatum、C.circinans和C.capsici的许多菌株有相似或完全一致的内切酶酶切图谱,这些分子特征支持它们为同一个种。     

加拿大一枝黄花与相似种的区别及防除

本文就加拿大一枝黄花的特征特性以及与3个相似种的区别、在我国的分布和生境情况进行了描述，并对加拿大一枝黄花的防除方法和策略进行了总结。