Exogenous trehalose alleviates the inhibitory effects of salt and drought stresses in okra plants

Trehalose (Tre) is essential for metabolic regulation and confers abiotic stress tolerance in a wide range of organisms. There is limited knowledge about the physiochemical and biochemical mechanisms by which Tre enhances salt and drought tolerance in okra plants. In the present study, the utilization of a 10 mM concentration of Tre substantially improved salt tolerance and drought resistance of okra plants. A notable augmentation in osmotic adjustment compounds (trehalose, proline, soluble protein, and soluble sugar), photosynthetic pigments (chlorophyll a and b, total carotenoids), and a marked reduction in oxidative stress markers, including hydrogen peroxide (H2O2), malondialdehyde (MDA), and electrolyte leakage rates, were observed in Tre-treated okra plants subjected to salt and drought stress. Moreover, in the presence of salt stress, okra plants treated with 10 mM Tre displayed a significant increase in K+ content and K+/Na+ ratio, along with a notable decrease in Na+ content. Additionally, these Tre-treated okra plants demonstrated elevated levels of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) during periods of salt and drought stress. The results of this study indicate that exogenous Tre supplementation enhances salt and drought tolerance in plants by modulating osmotic adjustment substances, protecting photosynthesis, maintaining ion homeostasis, and activating reactive oxygen species (ROS) scavenging systems. These findings underscore the importance of Tre in regulating plant resistance mechanisms and suggest that its use as a biostimulant could offer novel strategies for enhancing crop productivity in saline environments.