Rhizosphere competence of Trichoderma harzianum
Rhizosphere competence of Trichoderma harzianum
复制标题
哈茨木霉根际能力
DOI：
10.1094/phyto-77-182
复制
发表时间：
1987
期刊：
影响因子：
3.2
通讯作者：
J. S. Ahmad
中科院分区：
文献类型：
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作者：
J. S. Ahmad
测定了哈茨木霉在菜豆、黄瓜、玉米、萝卜和番茄根中的根球活性。当种子被野生型分生孢子包被，并在土壤中发芽，在恒定的基质势下，没有额外的水添加，真菌没有检测到在根的根际从1至8厘米深8天后。然而，当每克土壤中加入10微克苯菌灵时，耐苯菌灵的突变体是根际活性的。这些突变体在苯菌灵不加的情况下也能感受根际。突变体在根际的定殖程度不同。苯菌灵、土壤pH值和温度对哈茨木霉的生长有影响。本文提供的证据表明，一种根际无效的生物防治剂是通过突变而被诱导成根际有效的。（9，19，28）、立枯丝核菌（Rhizoctonia solani Kühn）（12-17，19，26，31）和小核菌属（Sclerotium spp.）（1、4、9、13、26、36）。它还增加了种子发芽和促进植物生长（7，37）。而用木霉处理种子。减少出苗前猝倒（20），成熟植物的后期保护尚未实现，主要是因为木霉属。不是根际主管（8，26）。因此，在讨论会和研讨会（如，5），需要经常表示诱导这样的拮抗剂不仅定殖精球，但也发展的根。Menu-Castro和亚历山大的报告（23）提出了一种建立以前根际无能力的方法。
Rhizosphere competence of Trichoderma harzianum was measured for roots of bean, cucumber, maize, radish, and tomato. When seeds were coated with conidia of the wild type and germinated in soil under constant matric potential with no additional water added, the fungus was not detected in the rhizospheres of roots from 1-to 8-cm depths after 8 days. Mutants tolerant to benomyl, however, were rhizosphere-competent when10 ug of benomyl was added per gram of soil. These mutants' were also rhizosphere-competent when benomyl was not added. The degree of rhizosphere colonization by mutants of T. harzianum was influenced by benomyl, soil pH, and temperature. Evidence provided herein indicates that a rhizosphere-incompetent biological control agent was induced by mutation to become rhizosphere-competent.Trichoderma harzianum Rifai is a biological control agent effective against Pythium spp.(9, 19, 28), Rhizoctonia solani Kühn (12-17, 19, 26, 31), and Sclerotium spp.(1, 4, 9, 13, 26, 36). It also increased seed germination and enhanced plant growth (7, 37). Whereas seed treatment with Trichoderma spp. reduced preemergence damping-off (20), later protection of the mature plant has not been realized mainly because Trichoderma spp. were not rhizosphere-competent (8, 26). Therefore, in discussion sessions and workshops (eg, 5), the need is frequently expressed for inducing such antagonists to colonize not only the spermosphere but also the developing root. The report by Mendez-Castro and Alexander (23) suggested a method for establishing previously rhizosphere-incompetent