EXOGENOUS APPLICATION OF POTASSIUM MITIGATES SALT STRESS AND ENHANCES SOYBEAN GROWTH THROUGH IMPROVED PHOTOSYNTHETIC EFFICIENCY, ANTIOXIDANT ACTIVITIES, AND IONIC HOMEOSTASIS

Salinity is a major abiotic stress that significantly reduces crop yields worldwide.Potassium possesses an excellent potential to induce abiotic stress tolerance in plants.This study aimed to evaluate the effects of potassium on salt tolerance in salt-sensitive and salt-tolerant soybean cultivars.The study was included salinity stress along with potassium levels (control, 60 mM NaCl, 120 mM NaCl, 60 mM NaCl + 6 mM K, 60 mM NaCl + 9 mM K, 120 mM NaCl + 6 mM K, and 120 mM NaCl + 9 mM K) and soybean cultivars: William 82, Ajmeri, AARI 62, and AARI 13.Salinity caused a profound decrease in growth and biomass production by decreasing relative water contents (RWC), chlorophyll contents, membrane stability index, leaf area, photosynthetic rate, transpiration rate, stomata conductance, intercellular carbon dioxide (CO2) concentration, potassium (K) accumulation and increasing accumulation of sodium (Na) and Na/K.The exogenous application of K mitigated the adversities of salinity which was linked with improved relative water contents (RWC), chlorophyll contents, membrane stability index, leaf area, photosynthetic rate, transpiration rate, stomata conductance, inter-cellular CO2 concentration, potassium (K) accumulation and decreasing accumulation of sodium (Na) and Na/K.Cultivar AARI 62 was identified as salt-tolerant, whereas cultivar Ajmeri was salt-sensitive.In conclusion, potassium application mitigates the adverse effects of salinity on soybeans by enhancing photosynthetic efficiency, antioxidant activity, and ionic homeostasis.