14株芽胞杆菌菌株的分子鉴定及其促生机理分析

以前期筛选的14株植物促生细菌为实验材料,运用16S rRNA基因序列同源性对菌株进行分子鉴定,通过生物测定评价菌株对番茄的促生效果,并对其促生机理进行初步分析。实验结果表明,促生菌株来自芽胞杆菌科的2个属、9个种。对番茄种子促生特性研究表明,14株芽胞杆菌均能提高种子发芽率,增长率为0.74%~11.85%;其中12株芽胞杆菌能促进胚根生长,增长率为4.03%~65.33%;而8株芽胞杆菌促进胚芽生长,增长率为1.24%~18.17%。对不同芽胞杆菌的促生因子相关分析结果表明,芽胞杆菌的6个促生因子（解无机磷、解有机磷、固氮效能、吲哚-3-乙酸含量、植酸酶活性、吡咯喹啉醌浓度）之间无相关关系（P>0.05）,与活菌数无相关关系（P>0.05）,与种子发芽率、胚根长、胚芽长也无显著相关关系（P>0.05）。种子发芽率与胚根长、胚芽长无相关关系（P>0.05）,而胚根和胚芽长之间具有显著性相关（P<0.01）。室内番茄盆栽实验表明,试验的6株芽胞杆菌对番茄幼苗均有促生作用,不同芽胞杆菌对番茄促生特性存在差异,如图瓦永芽胞杆菌FJAT-47648能显著增加根长,提升地上部与地下部干重,而暹罗芽胞杆菌FJAT-47226的促生效果则主要表现在增加株高和地上部生物量上。

Molecular Identification and Growth Promoting Mechanisms of 14 Bacillus Strains

Using 14 strains of plant growth promoting bacteria screened in the laboratory as the experimental materials,and the 16S rRNA gene sequence homology was used for molecular identification.The bioassay was used to evaluate its promoting effect on tomato growth,and its promoting mechanism was analyzed.The 14 strains were from 2 genera and 9 species of Bacillus.The inorganic phosphorus,organophosphorus,nitrogen fixation efficiency,IAA content,PQQ concentration and phytase activity of different Bacillus strains were different.The study on seed growth promoting characteristics showed that all the 14 strains could improve the germination rate of seeds with an increase rate of 0.74% to 11.85%.12 strains could promote the growth of radicle with an increase rate of 4.03%-65.33%.Eight strains could promote the growth of germ,increased from 1.24% to 18.17%.The correlation analysis of growth promoting factors of different Bacillus strains showed that there was no correlation between the growth promoting factors(P>0.05),and the number of viable bacteria(P>0.05),and there was no significant correlation between them and seed germination rate,radicle length and germ length(P>0.05),but there was a significant correlation between radicle length and plumule length(P<0.01).The effect of 6 Bacillus strains on rhizosphere growth promotion was further verified by the pot experiment in the laboratory.The results showed that Bacillus had an effect on the growth promotion of tomato seedlings.For example,Bacillus toyonensis FJAT-47648 could significantly increase the root length of the plant,and also increase the aboveground and underground biomass while Bacillus siamensis FJAT-47226 could significantly increase the plant height and aboveground biomass.