EXOGENOUS APPLICATION OF POTASSIUM DIHYDROGEN PHOSPHATE CAN ALLEVIATE THE ADVERSE EFFECTS OF SALT STRESS ON SUNFLOWER

Abstract

A greenhouse experiment was conducted to examine whether foliarly applied potassium + phosphorus (K + P) in the form of monopotassium phosphate (KH₂PO₄) could mitigate the adverse effects of salt stress on sunflower plants. There were two levels of root-applied salt [0 and 150 mM of sodium chloride (NaCl)], and varying levels of KH₂PO₄ [(NS (no spray), WS (spray of water), 5 + 4, 10 + 8, 15 + 12, and 20 + 16 mg g⁻¹ K + P, pH 6.5] applied foliarly to 18-day old non-stressed and salt stressed sunflower plants. Salt stress adversely affected the growth, yield, photosynthetic capacity, and accumulation of mineral nutrients in the sunflower plants. However, varying levels of foliar applied KH₂PO₄ proved to be effective in improving growth and yield of sunflower under salt stress. The KH₂PO₄ induced growth in sunflower was found to be associated with enhanced photosynthetic capacity, water use efficiency and relative water contents.

Keywords:

• KH₂PO₄
• supplementary K + P
• salt stress
• mineral nutrients
• photosynthetic capacity