Isolation, identification and effect of saline-alkali tolerant growth-promoting bacteria in rhizosphere of Radix Paeoniae Rubra

To enrich the growth-promoting bacteria resources in the rhizosphere of Radix Paeoniae Rubra, functional medium was used to isolate, screen and identify rhizosphere growth-promoting bacteria, and their growth-promoting effects were evaluated by seed germination and seedling growth experiments. In this study, rhizosphere soil of Radix Paeoniae Rubra root in saline-alkali soil was used, and saline-alkali tolerant strains C14 and C31 with growth promotion function were screen out. The two strains were identified by morphology and molecular biology as Bacillus aerophilus and Bacillus siamensis, respectively. Strain C14 performed significantly better than strain C31 in promoting growth, and then C14 was selected for further study. The seed germination experiment showed that the germination rate, germination potential, germination index and vitality index of Radix Paeoniae Rubra seeds with the treatment of C14 strain (10⁷ CFU·mL⁻¹) for 48 h were increased by 29.5%, 44.0%, 30.6% and 55.5%, respectively. After treatment with C14 strain, root length, dry weight and fresh weight also increased to some extent. These results provide a reserve strain resource for further exploration of the function of saline-tolerant growth-promoting bacteria and improvement of saline-alkali soil.