柠条根际产铁载体促生菌的分离鉴定及其促生特性

Isolation and Identification of Siderophore-producing Rhizobacteria From Rhizosphere Soil of Caragana spp. and Its Growth-promoting Effects

以柠条根际土壤为试材,采用CAS(铬天青S)选择性培养基分离筛选具有产铁载体功能的根际促生菌株,通过16S r DNA序列分析进行菌株鉴定,并测定菌株解磷、固氮、产IAA(吲哚乙酸)和ACC(1-氨基环丙烷-1-羧酸)脱氨酶等促生活性,通过盆栽试验分析验证菌株Fe11对柠条幼苗生长的影响。结果表明:共分离出14株产铁载体根际促生菌,其中6株菌具备较强的产铁载体能力。所有菌株的16S r DNA序列同源性与假单胞菌达到99%~100%,假单胞菌属细菌是柠条根际产铁载体的优势菌群。多数菌株兼具2种以上促生活性,菌株Fe9、Fe11和Fe13表现出多种促生潜能。回接试验证实,接种菌株Fe11使柠条幼苗的株高、根长、叶片数、鲜质量和干质量分别增长17.25%、6.68%、17.75%、42.51%和20.67%,表明菌株Fell对柠条的生长具有良好的促进效果。

Rhizobacteria of producing siderophore were isolated from rhizosphere soil of Caragana spp.grown in desert grassland with CAS（ chrome azurol S） medium. The diversity of the strains were analysed based on the 1 6 S r DNA sequences. The ability of phosphate dissolving,nitrogen fixation,indoleacetic acid（ IAA） and ACC deaminase production were evaluated. The effect on promoting growth of Caragana spp.seedlings were tested by inoculating experiment with strain Fe11. The results showed that total of 14 strains of siderophore-producing were isolated from rhizosphere soil of Caragana spp.,and 6 of them had strong ability to produce siderophore. The 16 S r DNA sequences of all strains had 99%-100%similarity with that of Pseudomonas,which was dominant siderophore-producing rhizobacteria of Caragana spp.Most of the strains had more than two kinds of growth-promoting characteristics.Among them,strains Fe9,Fe11 and Fe13 showed a diverse growth-promoting potential.The results of inoculation experiment demonstrated that strain Fe11 had obvious growth-promoting effect on Caragana spp. seedlings. The plant height,root length,leaf number,fresh weight and dry weight were increased by 17. 25%,6. 68%,17. 75%,42. 51% and 20. 67%,respectively.