Effects of Gibberellic Acid Pretreatment on Germination, Early Growth, and Stress Responses of Mung Bean (Vigna radiata (L.) R. Wilczek) under Water Deficit and Salinity

Water deficiency and salinity are critical abiotic stresses that reduce plant productivity, whereas seed priming with gibberellic acid (GA3) enhances germination and growth by modulating key physiological and biochemical mechanisms under these stress conditions. This study aims to evaluate the physiological and biochemical effects of GA3 seed pretreatment on two mung bean (Vigna radiata (L.) R.Wilczek) varieties, MB1 (Argentina) and MB2 (Uzbekistan), under simulated water deficit and salt stress conditions, both individually and in combination. The seeds of each variety were divided into two groups: the first group served as a control and was pretreated with 100 mL of pure water (0 mg/L GA3), while the second group received a 200 mL solution of GA3 (200 mg/L) for 24 h. We then exposed the seeds to simulated water deficit stress conditions using 10% (w/v) polyethylene glycol (PEG 6000) and salinity conditions with 50 mM NaCl. Various physiological and biochemical parameters were analyzed, including root and shoot length, fresh and dry weight, DPPH (2,2'-diphenyl-1-picrylhydrazyl radical) scavenging activity (%), total phenolic content (TPC), and total flavonoid content (TFC). The findings of this study indicated that exogenously applied GA3 improved the physiological parameters and enhanced the ability of non-enzymatic antioxidants to cope with water deficiency- and salinity-driven oxidative damage in the MB2 variety. However, GA3 treatment did not improve TPC and TFC in the stressed groups of the MB1 variety. The study highlights the importance of considering genotype-specific responses to seed priming treatments in mung beans, emphasizing the need to tailor optimal plant growth regulator precursor agents to specific genotypes. Additionally, the study highlights the role of osmotic adjustment mechanisms and antioxidant defense pathways in enhancing plant cell tolerance to water deficit and salt stress. Further research is needed to fully understand how gibberellic acid pretreatment works at the physiological and biochemical levels.