Role of Salicylic Acid in Mitigating Stress and Improving Productivity of Crops: A Review

Plant stress encompasses the alterations occurring in plants when confronted with adverse environmental conditions. These conditions, though not immediately life-threatening, trigger alarm signals within the plants. Stress can arise from two primary factors: abiotic stress, such as drought, heat, or salinity, and biotic stress, caused by pathogens like insects, viruses, or bacteria. Plant growth regulators (PGRs) serve as an effective method to assist plants in coping with stress. Salicylic acid (SA), a crucial PGR, regulates various facets of plant growth and development. It influences seed germination, organ development, stomatal movement, photoperiodic responses, and aging. SA aids plants in combating environmental stressors like cold, heat, drought, and salinity, while also bolstering defenses against diseases. External application of SA becomes necessary when the natural levels in plants are insufficient to manage stress. SA can be derived from willow bark, extracted from plants like mango or broccoli, or synthesized from phenylalanine or phenol. Its application during stress conditions triggers protective antioxidant responses, enhances nutrient uptake under salinity, aids photosynthesis and metabolite movement in heat stress, and promotes root development and resilience to waterlogging. SA's interactions with other PGRs like auxin, ethylene, and abscisic acid further assist plants in tolerating multiple stressors. Although research has explored SA's role in mitigating individual stresses, further investigation is needed, particularly in real-world field conditions where plants face concurrent stressors.