饲用玉米根际促生菌资源筛选及其特性研究

为获得玉米根际促生菌(PGPR)菌株并明确其功能特性;以玉米根系及根际土壤为材料,利用选择性培养基分离筛选溶磷菌与固氮菌,测定所选菌株溶磷能力和固氮酶活性,并测定其产IAA的能力,从中筛选综合性能优良的菌株,在此基础上,运用生理生化鉴定和16SrDNA分子生物学鉴定相结合的方法鉴定优良菌株的种属。结果表明:玉米根际有大量PGPR菌,分布特征表现出根表(RP)根表土(RS)远根土(NRS)根内(HP)的数量分布规律,呈根际效应。最终获得262株PGPR菌,其中固氮菌48株,溶解无机磷细菌108株,溶解有机磷细菌106株,有分泌IAA能力的菌株15株。筛选出综合性能优良、有进一步开发应用潜力的菌株7株。经鉴定其中3株为Pseudomonas fluorescens;2株为Bacillus subtilis;Klebsiella oxytoca和Bacillus megaterium各1株。

Study on screening and characteristics of PGPR isolated from maize

In order to obtain the plant growth promoting rhizobacteria (PGPR) from maize and identify the function,the phosphate-solubilization bacteria and nitrogen fixation bacteria were isolated by using rhizosphere soil and selective medium.The potential PGPR strains were screened by measuring the phosphate-solubilization capacity (organic phosphorus and inorganic phosphorus),nitrogen fixation capacity and IAA secretion capacity.And then,the potential strains were identified through physiological and biochemical tests,as well as 16SrDNA sequence analyses.The number of PGPR shown the following order: RP (rhizoplan or root surface) > RS (root soil) > NRS (soil away from roots) > HP (histoplan or root interior).Totally 262 PGPR strains were isolated from the maize rhizosphere,including 48 nitrogen fixing strains,108 inorganic phosphorus-solubilization strains,106 organic phosphorus-solubilization strains and 15 inorganic phosphorus-solubilization strains.In which,7 strains were excellent and had application potential (3 strains were Pseudomonas fluorescens,2 strains were Bacillus subtilis,1 strain was Klebsiella oxytoca and 1 strain was Bacillus megaterium).