Abstract:
Salinity is one of the major soil problems that limits the crop growth and productivity to great extent. Increased amount of soluble salts cause osmotic stress and excessive sodium (Na+) leads to sodicity that deteriorate the soil structure and cause toxicity to plants. Potassium (K+) is an important macronutrient essential for enzyme activation, osmoregulation and charge balance in the plant cell. Higher concentration of Na+ in nutrient medium decreases K+ uptake and increases Na+ uptake by plants. Therefore under sodic or saline-sodic conditions K+/Na+ ratio in plant tissue is decreased affecting enzyme activities, photosynthesis, protein synthesis and other metabolic activities. Elevated K-fertilization under Na+ stress may improve the K+/Na+ ratio in plant tissue improving plant metabolism under saline-sodic condition. Na+-K+ interaction in saline- sodic soils was studied in light and heavy textured soils. Different levels of Na+ stress was applied to developed higher SAR of the soil using NaCl. Na+-K+ dynamics was compared with naturally salt affected soils at elevated K-fertilization. Effect of elevated K- fertilization on wheat crop growth, distribution of Na+ and K+ in different parts of the plants, subcellular Na+-K+ homeostasis of wheat under Na+ stress and proteome stability was determined in soil and hydroponic studies. Plant growth, physiological and chemical attributes, yield was significantly reduced under salt stress while application of elevated potassium fertilization improved growth and yield parameters. Application of elevated K fertilization mitigate osmotic, ionic and oxidative stress under saline condition improving subcellular K+/Na+ ratio. Elevated potassium fertilization improved proteome stability under salt stress decreasing the change in number of proteins changed by salt stress. This study suggest that K application could enhance wheat growth and yield by mitigating the deleterious effects of salt stress to a certain level at specific condition.
