黑果枸杞根际促生菌筛选与特性研究

为获得黑果枸杞根际促生菌(PGPR)菌株并明确其促生特性,以黑果枸杞根系及根际土壤为材料,利用选择性培养基分离筛选固氮菌与溶磷菌,测定其固氮酶活性和溶磷能力,并对性能优良的菌株利用生理生化鉴定和16SrDNA分子生物学鉴定相结合的方法鉴定。结果表明:根际促生菌数量的分布具有根系表面(RP)根表土壤(RS)根内(HP)的规律,有明显的根际效应;经分离纯化获得71株PGPR菌,其中,固氮菌21株,且7株菌株的固氮酶活性大于200nmol C2H4/(h·mL);溶解无机磷菌株30株和溶解有机磷菌株20株,13株溶磷量高于300μg/mL的溶磷菌株;综合分析,有6株具有进一步开发应用潜力,且均为Bacillus。研究结果为研制生物菌肥提供了优良菌种,也丰富了优良根际促生菌资源库。

Identification of plant growth promoting rhizobacteria Lycium ruthenicum and their effectives

In order to obtain plant growth-promoting rhizobacteria and clarify their growth-enhancing efficiency to Lycium ruthenicum,the root morphology and rhizosphere soil in L.ruthenicum Murr were collected.The strains of nitrogen-fixing and phosphate-solubilizing bacteria were separated with selective medium and the potential PGPR strains species were identified by physiological and biochemical characteristics and 16SrDNA sequence analysis.Result showed that the quantities of bacteria and PGPR represented a distribution trend of ‘rhizosplan or surface of roots (RP) ＞ soil adhering to roots (RS) ＞ histoplan or interior of roots (HP)’,that denoted a strong rhizosphere effect.We isolated 71 PGPR bacteria strains,which contained 21 nitrogen-fixing bacterial strains,30 inorganic phosphate-solubilizing bacterial strains and 20 organic phosphate-solubilizing bacterial strains.There were 7 strains of nitrogenase activity higher than 200 nmol C2H4/(h · mL),and 13 strains of phosphate solubilizing activity reached 300 μg/mL.A further 6 potential PGPR strains had been identified as Bacillus sp.This study offered potential PGPR for the development of microbial fertilizers and enriched the PGPR resources.