Abstract:

This study aimed to screen salt-tolerant plant growth-promoting rhizobacteria from the rhizosphere soil of common bean grown in saline-alkali soil that could enhance the growth of common bean seedlings under salt stress, so as to lay a foundation for the development of salt-tolerant microbial inoculants for common bean. Using the rhizosphere soil of common bean in saline-alkali soil and the salt-sensitive common bean cultivar 'A18' as experimental materials, strains were screened by methods such as the Salkowski colorimetric method, and a pot experiment was conducted for verification. The growth and physiological indices of common bean seedlings were determined. The results showed that under salt stress, the root length, aboveground fresh weight, aboveground dry weight and root dry weight of common bean seedlings decreased by 49.43%, 16.72%, 17.07% and 25%, respectively, compared with the control group. Inoculation with strain B10 exhibited the most significant growth-promoting effect on common bean seedlings under salt stress. Compared with the salt stress treatment alone, inoculation with strain B10 under salt stress increased the root length, aboveground fresh weight, root fresh weight, aboveground dry weight and root dry weight of common bean by 81.53%, 35.12%, 37.41%, 55.88% and 55.56%, respectively, all of which reached significant difference levels. According to the experimental results, strain B10 can promote the growth of common bean seedlings under salt stress and can be further used to develop related salt-tolerant microbial inoculants.

Key words: saline-alkali soil, salt stress, plant growth-promoting rhizobacteria, plant rhizosphere soil, salt-tolerant plant growth-promoting bacteria, microbial inoculant, common bean seedlings