黑果枸杞根际促生菌的筛选鉴定及促生能力分析

Isolation and identification of growth-promoting rhizobacteria fromLycium ruthenicumsoil and their promoting effects

以新疆阿克陶县盐碱地中生长的黑果枸杞(Lycium ruthenicum)根际土壤为材料,分离兼具耐盐和良好促生能力的根际促生菌,共得到43株能够耐受1mol/L NaCl的菌株,其中13株具有溶磷和产铁载体能力,进而在13株菌中筛选出7株具有分泌生长素能力的菌株.通过溶磷、产吲哚乙酸等功能指标对比,选择出4株功能较强的菌株进行盆栽促生实验,结果发现菌株H29和X49能显著促进盐胁迫下黑果枸杞幼苗的生长.与阴性对照相比,H29处理植株的株高、叶片数、根长、地上部鲜质量和干质量分别增加32.86%,41.67%,44.76%,175.00%和114.29%,X49处理植株的根长、根表面积、地下部鲜质量和干质量分别增加51.75%,130.05%,200.00%和250.00%.分子鉴定结果显示H29为链霉菌属(Streptomyces)菌株,X49为微杆菌属(Microbacterium)菌株.上述结果可为开发和推广适合盐碱化土壤的专用生物肥料提供优良菌种.

The rhizosphere soil was exploited from Lycium ruthenicum fields in Akto County of Xinjiang to isolate rhizosphere bacteria with both salt tolerance and the desirable growth-promoting ability.We obtained 43 isolates in total,and all isolates were capable of withstanding 1 mol/L NaCl.From the obtained NaCl-tolerant bacteria,we isolated 13 strains with good tricalcium phosphate-solubilization and siderophore-secretion abilities,and among them,further isolated 7 strains with the ability to produce plant hormone indolo acetic acid(IAA).According to comparative functional analysis,we selected 4 strains with more desirable multi-functional indexes to carry out growth-promoting experiments using pot-cultivated plant materials(i.e.L.ruthenicum seedlings).Compared with the negative control(non-bacteria-treated),H29-treated plants exhibited increases in height,leaf number,root length,upground fresh and dry mass by 32.86%,41.67%,44.76%,175.00% and 114.29%,respectively;and X49-treated plants showed increases in root length,root surface area,underground fresh and dry mass by 51.75%,130.05%,200.00% and 250.00%,respectively.In addition,molecular characterization identified H29 and X49 as genus Streptomyces and Microbacterium,respectively.The above results presented bacteria resource which could be beneficial for developing salinity-soil-specialized bio-fertilizers and their application.