Potassium-induced decrease in cytosolic Na⁺ alleviates deleterious effects of salt stress on wheat (Triticum aestivum...

Area of Science:

• Plant Science
• Agricultural Science
• Environmental Science

Background:

• Soil salinity, caused by sodium chloride (NaCl) accumulation, induces osmotic stress and ion toxicity in plants.
• High salinity disrupts plant potassium (K+) uptake and increases K+ efflux, leading to a decreased K+/Na+ ratio.
• This K+/Na+ imbalance negatively impacts enzyme activity, osmoregulation, and cellular charge balance, hindering plant growth.

Purpose of the Study:

• To investigate the effect of elevated potassium (K+) concentrations on wheat growth and grain yield under varying salinity levels.
• To determine how different K+ levels influence the distribution of sodium (Na+) and K+ in wheat tissues and cytosol.
• To assess the impact of K+ and salinity on physiological parameters like photosynthesis and water potential.

Main Methods:

• Wheat was cultivated with varying K+ concentrations (2.2, 4.4, 8.8 mM) under different NaCl salinity levels (1, 60, 120 mM).
• Measurements included fresh and dry weight, grain yield, root and shoot Na+ and K+ content, and cytosolic Na+ concentration.
• Photosynthesis rate and water potential were also analyzed to understand physiological responses.

Main Results:

• Salinity significantly reduced fresh weight (shoots and roots) and dry weight (roots).
• Grain yield decreased under salinity stress but was improved by elevated K+ fertilization.
• Higher K+ levels prevented Na+ accumulation in shoot and root protoplast cytosol, mitigating toxicity.

Conclusions:

• Moderately elevated K+ application effectively reduces both tissue and cytosolic Na+ concentration in wheat seedlings.
• Enhanced K+ levels mitigate the detrimental effects of Na+ toxicity, leading to improved wheat growth and grain yield.
• While high K+ transiently affected vegetative growth, it ultimately boosted grain yield, highlighting its importance in salinity management.