田菁根际促生菌的筛选及其促生耐盐效果

Screening of plant growth promoting and salt tolerant rhizobacteria in Sesbania cannabina

摘要:

[目的]为探究盐生植物田菁及其根际功能微生物改良盐碱地的效果，本研究从黄河三角洲盐碱区田菁根际土壤中分离促生菌，并明确其耐盐促生效果。[方法]采用选择培养方法从田菁根际土壤中分离固氮菌、解磷菌以及解钾菌，并进行16S rRNA分子生物学鉴定。之后对菌株的耐盐及促生特性进行测定，筛选性状优良菌株进行玉米促生作用研究。[结果]共分离得到105株根际促生菌，其中N102兼具多种促生特性且耐盐性达15%。田菁种子发芽试验表明，N102可显著提高田菁发芽率（47%，P<0.05）、芽长（48.5%，P<0.05）和根长（60%，P<0.05）；玉米盆栽试验结果表明，N102对盐胁迫下玉米的株高、根长、叶绿素含量、地上部干重以及根干重具有显著的促进作用。经系统发育分析，N102与Enterobacter soli ATCC BAA-2102（NR117547）序列相似度为99.30%，鉴定属于Enterobacter属。[结论]菌株N102具有多种植物促生耐盐特性，具有开发成有效促进盐碱地作物生长的微生物肥的良好前景。

Abstract:

[Objective] To explore the effects of halophyte Sesbania cannabina and its rhizosphere functional microorganisms on ameliorating saline alkali soil, we isolated and identified the plant growth promoting rhizobacteria (PGPR) of S. cannabina grew in saline-alkali soil of Yellow River Delta, and further studied the growth-promoting and salt-tolerant characteristics of PGPRs. [Methods] Nitrogen-fixing, phosphorus-dissolving and potassium-dissolving bacteria were isolated from rhizosphere soil of S. cannabina by selective culture and identified by 16S rRNA molecular biology. Traits of plant growth-promoting and salt tolerance of the strains were determined and analyzed, and strains with excellent traits were selected to further study their growth promotion effect on corn. [Results] We totally obtained 105 rhizosphere isolates, of which N102 had growth-promoting and salt tolerance activities. As shown by seed germination test, N102 could significantly increase the germination rate (47%, P<0.05), bud length (48.5%, P<0.05), root length (60%, P<0.05) of S. cannabina. The pot experiment also shows that N102 could significantly improve plant height, root length, shoot dry weight, root dry weight and chlorophyll content of corn under salt stress. According to phylogenetic analysis, the similarity between N102 and Enterobacter soli ATCC BAA-2102 (NR117547) sequence was 99.30%, this it was identified as Enterobacter genus.[Conclusion] Strain N102 has high salt-tolerant and plant growth-promoting characteristics, promising to develop as microbial inoculants or microbial fertilizers that can effectively promote the growth of crops in saline-alkali soils.