植物促生菌培养条件优化及其对尾叶桉幼苗接种效应的研究

Optimal Culture Conditions of Plant Promoting Bacteria and Inoculation Effects on Eucalyptus Seedlings

以植物促生菌(PGPB)SZ7-1菌株为研究对象,首先,采用单因素试验设计及响应曲面分析法,优化SZ7-1的培养条件,并在5 L自动发酵罐中进行培养;其次,通过温室盆栽试验研究了该菌对桉树幼苗的接种效应。结果表明:(1)以菌体浓度(OD值)为目标值,在单因素试验的基础上,利用响应曲面法综合考虑3因素对SZ7-1生长的影响,得到了最优培养条件为:pH6.02、接菌量2.41%和装液量10%。由5 L自动发酵罐中培养可知,优化后的培养条件更利于菌株的生长,16 h后活菌数达到1.31×1010CFU/mL,是优化前的1.62倍;(2)接种后植株有较好的生长表现,在株高、地上和地下部分干重以及全氮含量等方面较对照有明显地增加。研究结果可为该类促生菌的大量培养和应用提供参考。

The optimal culture conditions of plant growth promoting bacteria SZ7-1 and growth effects of Eucalyptus seedling by inoculation were tested.Single-factor design and the response surface methodology was used to obtain the optimal culture conditions,and mass production of the strain was cultured in a 5 L auto fermentor.It was indicated that：（1） The optimum conditions for the growth of SZ7-1 were determined through singe-factor analysis.The interactions and optimization of the culture parameters for SZ7-1 was applied to study using the response surface methodology.The results showed that the optimum culture conditions for germination as follows：pH6.02,2.41％ inoculum size and 10％ volume of medium in flask.Analyzing the 5 L auto fermentor with two different culture conditions,the optimized culture conditions were testified to be more suitable for the growth of SZ7-1 strains,and live bacteria reached 1.31×l010CFU/mL,which was 1.62 times more than original culture condition.（2） Our results also indicated that the E.urophylla inoculated with SZ7-1 grew significantly better than the non-inoculated treatment,also increased in the plant biomass or nitrogen concentration.Hence,this study indicated that the strain SZ7-1 was a superior inoculant for growth-promotion on Eucalyptus seedling under greenhouse conditions,and provide some useful inoculation information for Eucalyptus plantation.