桑树肠杆菌对盐胁迫下红砂幼苗的促生效应及根际机理OA

In this study,we investigated the effects of plant growth-promoting rhizobacteria(PGPR)on the growth and rhizosphere soil of the desert plant Reaumuria songarica under salt stress.Seedlings of R.songarica were inoculated with the PGPR Enterobacter mori P4 and subjected to 400 mmol·L-1 NaCl stress,and seedling growth and physiological indicators,as well as soil characteristics and phosphorus functional gene abundance,were determined.The main results were as follows:1)Under salt stress,the R.songarica seedlings inoculated with P4 showed significantly increased total root length and seedling biomass,compared with those in the control(P<0.05).Specifically,the group inoculated with P4 showed a significant increase in total root length by 16.5%,as well as increased root dry weight,stem dry weight,and leaf dry weight(by 74.19%,160.71%,and 92.54%,respectively).2)Under salt stress,the seedlings inoculated with P4 showed significantly increased soluble sugar and soluble protein contents(by 64.30%and 18.63%,respectively),significantly lower malondialdehyde content(by 25.41%),and decreased proline content(by 3.72%),compared with the control group.3)Under salt stress,the activities of sucrase and phosphatase were significantly higher(by 89.64%and 51.06%,respectively),and the activities of amylase,urease and catalase were significantly lower(by 27.90%,43.87%,and 3.03%respectively),in the P4-inoculated seedlings than in the control group.4)The transcript levels of phosphorus cycle functional genes(gcd,pqqC,ppx,phoD,and phoX)were significantly lower in the rhizosphere soil of the control group than in that of the P4-inoculated seedlings,indicating that P4 can significantly increase the transcript abundance of these functional genes.In summary,P4 stimulates soil microorganisms to synthesize enzymes and increase the expression of genes in the phosphorus cycle,and promotes the accumulation of osmotic adjustment substances in R.songarica,allowing it to maintain cell turgor and enhance its salt tolerance.