Abstract: In order to explore the functional diversity of Avenna sativa L. rhizosphere microorganisms,the oat rhizosphere soil in the Sanjiangyuan region was used as object of this study. The physical and chemical properties of the rhizosphere soil were determined by conventional methods,and plant growth-promoting rhizobacteria (PGPR) were screened by plate coating method. The abilities of nitrogen fixation,phosphorus solubilization and indoleacetic acid production were explored. And the excellent strains were identified by 16S rRNA gene. Thirty one strains of excellent nitrogen-fixing bacteria,5 strains of phosphate-solubilizing bacteria and 13 strains of indoleacetic acid-producing bacteria were screened. There were significant differences in soil available nitrogen,total nitrogen,available phosphorus,total phosphorus,available potassium,total potassium,pH value and organic matter in different regions (P<0.01). There was a significant negative correlation between the total nitrogen content of rhizosphere soil and the number of PGPR (P<0.05). There was a significant positive correlation between the total phosphorus content,available potassium content,soil pH value,organic matter content and the number of PGPR (P<0.05). Six excellent PGPR strains were identified as Pseudomonas sp.,1 strain as Bacillus pumilus sp.,and 2 strains as Arthrobacter sp.. The number and functional diversity of oat rhizosphere strains in different regions,and the correlation between soil characteristics and PGPR amount.

Key words: Avenna sativa L., Azotobacter, Phosphate solubilization capacity, Soil physical and chemical properties, Functional diversity of strains

摘要： 为探究燕麦(Avenna sativa L.)根际微生物的功能多样性,本文以三江源区燕麦根际土壤为研究对象,采用常规方法测定根际土壤理化性质、平板涂布法筛选植物根际促生菌(Plant growth-promoting rhizobacteria,PGPR),探究其固氮、溶磷及产吲哚乙酸能力,并对优异菌株进行16S rRNA基因鉴定。本研究筛选得到优异的固氮菌31株、溶磷菌5株,产吲哚乙酸菌13株。各地区土壤碱解氮、全氮、速效磷、全磷、速效钾、全钾和有机质含量以及pH值存在极显著性差异(P<0.01)。根际土壤全氮含量与PGPR数量存在显著的负相关关系(P<0.05),根际全磷含量、速效钾含量、土壤pH值、有机质含量与PGPR数量存在显著的正相关关系(P<0.05)。6株优异PGPR鉴定为假单胞菌(Pseudomonas sp.),1株为短小芽孢杆菌(Bacillus pumilus sp.),2株为节杆菌(Arthrobacter sp.)。不同区燕麦根际菌株具有数量和功能多样性,土壤特性和PGPR量间呈相关关系。

关键词: 燕麦, 固氮菌, 溶磷能力, 土壤理化性质, 菌株功能多样性