Seed priming with plant growth-promoting rhizobacteria and supplementation of culture medium with biochar alleviated salinity damages in Prosopis koelziana seedlings.

The Prosopis koelziana genus, a member of the Fabaceae family, is crucial to the ecology and economy of arid areas. It is commonly used to restore deserts, forests, and degraded soil with low fertility and high salt concentration. However, recent studies found that the seedlings of P. koelziana are highly susceptible to salinity stress despite having a high tolerance to it. To address this issue, an experiment was conducted to determine if plant growth-promoting rhizobacteria (PGPR) pretreatment and biochar application could enhance the seedlings' tolerance to saline conditions. The research showed that salinity stress decreased seedling growth but increased proline content, soluble sugar content, and antioxidant enzyme activity. Na+ ions increased in plants under salt stress, while K+ ions decreased. The results indicated that the pretreatment of plants with biochar and bacteria increased the fresh weight of seedlings by about 23%, 58%, and 50% in 200, 400, and 600 mM NaCl, respectively, compared with non-pretreated plants. Biochar and bacteria application also increased the proline content by about 62%, 46%, 32%, and 45% in 0, 200, 400, and 600 mM NaCl. This experiment showed that bacteria and biochar pretreatment of plants reduced oxidative stress and sodium uptake (20%, 28%, and 10% decrement of root Na uptake in 200, 400, and 600 mM NaCl). Therefore, these two bio stimulators should be used together for more significant effects on the salinity mitigation of P. Koelziana seedlings and the production of resistant seedlings that have a high ability to transfer to the field. [ABSTRACT FROM AUTHOR]