[Screening and evaluation of saline-alkali-tolerant and growth-promoting bacteria].

Salinity is the most important factor for the growth of crops. It is an effective method to alleviate the toxic effect caused by salt stress using saline-alkali-tolerant and growth-promoting bacteria in agriculture. Seven salt-tolerant bacteria were screened from saline-alkali soil, and the abilities of EPS production, alkalinity reduction and IAA production of the selected strains were investigated. A dominant strain DB01 was evaluated. The abilities of EPS production, alkalinity reduction and IAA production of strain DB01 were 0.21 g/g, 8.7% and 8.97 mg/L, respectively. The isolate was identified as Halomonas aquamarina by partial sequencing analysis of its 16S rRNA genes, and had the ability to inhibit the growth of Fusarium oxysporum f. sp., Alternaria solani, Phytophthora sojae and Rhizoctonia cerealis. It also could promote root length and germination rate of wheat seedlings under salt stress. Halomonas aquamarina can provide theoretical basis for the development of soil microbial resources and the application in saline-alkali soil improvement.盐分是影响作物生长最重要的因素，使用能促进植物生长的耐盐碱促生菌减轻盐胁迫引起的损害是一种农业上的有效方法。文中从盐碱地筛选得到7 株耐盐细菌，并考察筛选菌株的产胞外聚合物 (EPS) 能力、降碱能力和产吲哚-3-乙酸 (IAA) 能力。经综合评价选出1 株优势菌株DB01，菌株DB01 产EPS 能力为0.21 g/g，降碱能力为8.7%，产IAA 的能力为8.97 mg/L。菌株经16S rRNA 鉴定为海水盐单胞菌Halomonas aquamarina，并且有抑制香蕉枯萎病、番茄早疫病、大豆疫霉病、小麦纹枯病病原菌的能力，同时能够在盐胁迫下促进小麦幼苗的发芽率和根长。海水盐单胞菌Halomonas aquamarina DB01 可为土壤微生物资源开发利用和盐碱地改良提供理论依据。.