刘兆良+袁忠林+周长健+罗兰

摘要：以小麦为初筛靶标生物，筛选到3株对其生长具有抑制作用的海洋放线菌。采用平皿法以反枝苋、生菜和黄瓜为供试植物，测定3株海洋放线菌的除草活性。结果表明，菌株SLR2、GC3、AF2发酵液的上清液对反枝苋、生菜和黄瓜的种子幼根和幼芽具有较强的抑制作用，其中3种菌株发酵液的上清液对反枝苋幼根和幼芽的抑制率为100%，5倍稀释液对反枝苋的抑制率均在50%以上；SLR2、GC3发酵液的上清液对生菜生长的抑制率为95.1%～100%和80.9%～100%；SLR2发酵液的上清液对黄瓜生长的抑制率为73.8%～77.4%。根据形态特征和16S rDNA 序列分析，将SLR2、GC3和AF2鉴定为原小单孢菌Promicromonospora umidemergens、浅多色链霉菌Streptomyces pluricolorescens和小链霉菌Streptomyces parvus。

关键词：海洋放线菌；除草活性；筛选；鉴定

中图分类号：S476.1 文献标识号：A 文章编号：1001-4942（2017）08-0063-06

Abstract Three marine actinomyces with inhibitory effect on the growth of wheat were screened. The herbicidal activity of the three strains were determined using the plate method and with Amaranthus retroflexus， Lactuca sativa and Cucumis sativus as the tested plants. The results showed that there were obvious inhibitory effects of SLR2， GC3 and AF2 fermentation supernatant fractions on young root and bud growth of A. retroflexus， L. sativa and C. sativus. The inhibition rates of SLR2， GC3 and AF2 fermentation supernatants on young roots and buds of A. retroflexus were all 100%， and those of their five times supernatant diluents were more than 50%. The inhibition rates of SLR2 and GC3 fermentation supernatants on L. sativa were 95.1%～100% and 80.9%～100%， respectively， and those of SLR2 fermentation supernatants on C. sativus were 73.8%～77.4%. Based on the 16S rDNA sequence and physiological properties， the strain SLR2， GC3 and AF2 were identified as Promicromonospora umidemergens， Streptomyces pluricolorescens and Streptomyces parvus respectively.

Keywords Marine actinomycetes； Herbicidal activity； Screening； Identification

雜草严重危害农作物的生长和发育，每年造成的损失约占世界粮食总产量的10%[1，2]。化学除草剂具有高效、快速、经济的优点，同时也带来了环境污染、杂草抗性等诸多问题[3-5]。因此，开发新型生物源除草剂已成为研制新农药的热点。

生物源除草剂以资源丰富、毒性小、残留少、环境兼容性好、经济效益高等优于化学除草剂的特点，逐步引起人们的重视[6-8]。有关放线菌或其分泌物被开发为商品作为除草剂应用于农业生产中的最早例子双丙胺磷（double propylamine phosphorus）就是产绿色链霉菌（Streptomyces viridocbromogenes）的产物，已经在日本开始商品化生产并销售，用来防治果园和非耕地一年或多年生杂草[1]。上海农药研究所发现的放线链霉菌产生的两类环己酰亚胺物质具有极强的除草活性，其发酵液的稀释液处理野苋苗后的防效可达100%[9]。……