生防菌株LB-1培养液对黄瓜的抑病促生作用

 LB-1为新筛选的生防近缘毛壳(Chaetomium subaffine)菌株。为明确LB-1培养液的抑病促生效果,本研究以黄瓜为供试植物,分别采用灌根和叶面喷施的方式,测定了LB-1培养液对黄瓜枯萎病和黄瓜白粉病的抑制效果;通过种子萌发、盆栽苗和生化检测试验,分析了LB-1培养液对黄瓜的促生作用。结果发现,LB-1培养液对黄瓜枯萎病抑制作用效果甚微,但对黄瓜白粉病生防效果明显,黄瓜叶片接菌24 h后叶面喷施LB-1培养液对白粉病的防效高达48.86%。LB-1培养液浸润催芽处理24 h的黄瓜种子萌发率和根长均显著高于对照(P=0.05),且LB-1培养液浸种、灌根、叶面喷施处理均能促进黄瓜幼苗的生长发育。LB-1没有产嗜铁素、产氢氰酸、固氮和溶磷能力,但能够产生吲哚乙酸(Indoleacetic acid,IAA)。表明生防菌株LB-1培养液能有效抑制黄瓜白粉病的发生,促进黄瓜种子萌发和植株生长,而且其促生作用可能通过产生IAA来实现。

Disease suppression and growth-promoting effects of the culture broth of a biocontrol strain LB-1 on cucumber

LB-1 is a newly screened biocontrol strain of Chaetomium subaffine.The disease suppression and growth-promoting effects of LB-1 culture broth were clarified with cucumber as donor plant in this study.The disease suppression effects on Fusarium wilt and powdery mildew of cucumber were detected using root-irrigation and foliar spraying methods,respectively;the growth-promoting effect on cucumber was evaluated through seed germination test,pot seedling experiment and biochemical assay.The results showed that LB-1 culture broth has little inhibitory effect on cucumber Fusarium wilt,but significant biocontrol effect on cucumber powdery mildew was obtained.The control efficacy on cucumber powdery mildew was reached to 48.86% when cucumber seedlings being foliar sprayed with LB-1 culture broth 24 h after the inoculation of Sphaerotheca fuliginea.The seed germination rate,root length of cucumber being treated with LB-1 culture broth for 24 h were significantly higher (P=0.05) than those of control cucumber seed.The growth and development of cucumber seedlings could be promoted when being treated with seed soaking,root irrigation or foliar spraying of LB-1 culture broth.No obvious siderophore production,hydrogen cyanide production,nitrogen fixation and phosphate solubilization abilities were detected from LB-1,but its indole acetic acid (IAA) production ability was prominent.These indicated that LB-1 culture broth could inhibit the occurrence of cucumber powdery mildew,promote the seed germination and seedling growth of cucumber,and its growth-promoting effect might be obtained through IAA production.