Methyl jasmonate (MeJA), as a plant growth regulator, which is involves in many morphological and physiological processes, plays an important role in defense systems of plants under stress conditions. However, the roles of physiological and biochemical mechanisms of enhancing salt tolerance of okra plants based on application of MeJA is poorly understood. In this study, the application of the investigated 50 μM MeJA significantly improved salt tolerance of okra plants based on the germination rates and culture pot experiment under salt stress. Based on optimal concentration of MeJA inducing salt tolerance of okra plants, application of 5 mM diphenyleneiodonium (NADPH oxidase inhibitor, DPI) and 50 μM MeJA + 5 mM DPI, respectively, significantly increased salt tolerance of okra plants. Assays on the content of component matter indicated the significant increases of JA, ABA, proline, soluble protein, soluble sugar, photosynthetic pigment and relative water, glutathione (GSH) and ascorbic acid (AsA) content and the significant decreases of hydrogen peroxide (H₂O₂), superoxide radicals (O²⁻) and malondialdehyde (MDA) content and electrolyte leakage rates were observed in okra plants with 50 μM MeJA under salt stress. The activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX) and peroxidase (POD) related to ROS scavenging were also enhanced in okra plants by applied MeJA under salt stress. Furthermore, the marked decreases of H₂O₂, O^2- and MDA content, and the significant increases of CAT, GR and APX activities and GSH and ASA content involved in ASA-GSH cycle were observed in MeJA-okra, DPI-okra and MeJA+DPI-okra plants under salt stress. H₂O₂ acted a toxic accumulation of ROS rather than as a second messenger for signal transduction in okra plants. These results demonstrate that exogenous MeJA increases the accumulation of JA, ABA and proline, which enhances salt tolerance of okra plants, by regulating osmotic balance and protecting membrane integrity and photosynthesis and activating ROS scavenging system. As a conclusion, treating okra plants with 50 μM MeJA could alleviate the harmful effects of abiotic stresses.

茉莉酸甲酯（MeJA）作为植物生长调节剂，参与植物的许多形态和生理过程，在植物胁迫防御系统中发挥着重要作用。然而，人们对基于 MeJA 的应用增强秋葵植物耐盐性的生理生化机制的作用知之甚少。在这项研究中，基于盐胁迫下的发芽率和栽培盆栽实验，研究的 50 μM MeJA 的应用显着提高了秋葵植物的耐盐性。基于诱导秋葵植物耐盐性的 MeJA 最佳浓度，分别施用 5 mM 二亚苯基碘铵（NADPH 氧化酶抑制剂，DPI）和 50 μM MeJA + 5 mM DPI，显着提高了秋葵植物的耐盐性。₂ O ₂）、超氧自由基（O ²⁻）和丙二醛（MDA）含量和电解质渗漏率在盐胁迫下50 μM MeJA秋葵植株中观察到。与 ROS 清除相关的超氧化物歧化酶 (SOD)、谷胱甘肽过氧化物酶 (GPX)、过氧化氢酶 (CAT)、谷胱甘肽还原酶 (GR)、抗坏血酸过氧化物酶 (APX) 和过氧化物酶 (POD) 的活性也通过应用 MeJA 在秋葵植物中得到增强盐胁迫。此外，在MeJA-秋葵、DPI-秋葵中观察到H ₂ O ₂、O ^2-和MDA含量显着降低，CAT、GR和APX活性以及参与ASA-GSH循环的GSH和ASA含量显着升高和盐胁迫下的 MeJA+DPI-秋葵植物。氢₂O ₂在秋葵植物中起到 ROS 有毒积累的作用，而不是作为信号转导的第二信使。这些结果表明，外源性 MeJA 增加了 JA、ABA 和脯氨酸的积累，从而通过调节渗透平衡、保护膜完整性和光合作用以及激活 ROS 清除系统来增强秋葵植物的耐盐性。总之，用 50 μM MeJA 处理秋葵植物可以减轻非生物胁迫的有害影响。