Isolation and Identification of Salt-Tolerant Rhizosphere Microorganisms

Abstract

With the continuous expansion of saline-alkali land in China, this study focuses on the rhizosphere microorganisms of the halophyte «Suaeda salsa» to improve soil cultivation conditions and ensure food security. Using the dilution plating and streak plate methods, strain 1-9 was isolated and purified to investigate its salt tolerance and plant growth-promoting functions. Selective medium tests revealed that this strain can tolerate 15% salinity and exhibits growth-promoting traits, including IAA production, ammonia production, nitrogen fixation, and phosphate solubilization. Plant experiments demonstrated that under salt stress, maize plants treated with strain 1-9 showed significantly enhanced salt resistance, with better stem and leaf growth compared to the control group. Measurements of dry matter accumulation and antioxidant enzyme activity further confirmed that the strain promotes maize growth under both normal and salt-stressed conditions, likely by enhancing antioxidant enzyme activity to improve stress resistance. This study provides theoretical and practical insights into the mechanisms of salt-tolerant microorganisms in promoting plant growth and offers a novel microbial-based ecological strategy for saline-alkali soil remediation.