巨菌草促生菌的筛选及其促生效应

Screening of growth promoting bacteria associated with Pennisetum sinese and their growth-promoting effect

以陕西和新疆两地采集的巨菌草为材料,从中筛选分离得到内生菌株103株,采用解磷、固氮和产IAA等筛选标准,对初筛菌株进行促生能力的测定,其中4株菌株同时具有多种促生作用;通过形态观察、生理生化和16Sr DNA序列分析,对这4株促生菌株进行分类鉴定,结果显示菌株XJ–4和SX–12均归属于肠杆菌属(Enterobacter),SX–30归属于芽孢杆菌属(Bacillus),XJ–12归属于寡养单胞菌属(Stenotrophomonas)。采用单菌接种和多菌混合接种小麦盆栽试验,测定促生菌的促生效应,结果表明,与对照组相比,多菌混合接种对小麦的促生效应优于单独接种处理的,经SX–30、SX–12和XJ–4混合菌液处理,小麦叶绿素含量增加了129.94%;经SX–12和XJ–4混合菌液处理,小麦幼苗鲜重增加了182.12%。

In the present study,Pennisetum sinese from Shaanxi and Xinjiang was used as the main research materia,from which 103 strains of endophytic bacteria were isolated.The plant growth promoting ability of these strains were screened based on their capacities of phosphate-solubilizing,nitrogen fixation,and production of indoleacetic acid,and 4 of these strains showed multiple growth promoting effects.Morphological observation,physiological and biochemical and 16S r DNA sequence analysis were conducted on the 4 growth promoting strains.The results showed strains XJ-4 and strain SX-12 belonged to Enterobacter,strain SX-30 belonged to Bacillus,and strain XJ-12 belonged to Stenotrophomonas.The growth promoting effects were further tested by wheat inoculation studies with individual strain or with strain combinations.Compared with the control group,growth promoting effects of the strain combinations were better than that of single strain:the chlorophyll content of wheat increased by 129.94%after treated with combination of strain SX-30,strain SX-12,and strain XJ-4;the fresh weight of wheat seedlings increased by 182.12%with combination of strain SX-12 and strain XJ-4.