Interplay between salicylic acid and nitric oxide in modulating mycorrhizal and rhizobial symbiosis in Vigna Radiata L mung bean under nickel stress

Abstract

This study aimed to assess the interactive effects of phytohormones (SA, NO) and mycorrhizal fungi (R. intraradices) on physiological and biochemical responses in Pusa-0672 mung bean plants under Ni-toxicity. Ni-induced detrimental effects on growth, symbiotic associations, and nutritional profile were emphasized. Roots exhibited a higher Ni-accumulation than shoots, impairing root/shoot ratios and mutualistic associations, resulting in diminished biomass accumulation. This metal stress prompted premature transitions to the reproductive cycle, adversely affecting pod formation and seed setting, leading to pod abortion and unhealthy seed production, ultimately reducing the harvest index. Ni-spiked conditions negatively impacted water uptake efficiency, soil enzymatic activity and nutrient acquisition potential (N, K, Fe, S, Mg, P, Zn). The addition of phytohormones (SA and NO) and mycorrhizal fungi (R. intraradices) enhanced tolerance, mitigating Ni-induced adversities and improving mung bean growth and yield potential. The ameliorators exhibited tissue-dependent effects, with better root biomass accumulation than shoots. The order of ameliorative strength was AM gt SA gt NO. Joint applications of SA+AM and SA+NO+AM were identified as promising strategies for imparting Ni-tolerance in mung bean plants, providing a theoretical basis for enhanced adaptability and agricultural outputs under Ni-stressed conditions. newline