| Abstract: | In order to assess the effectiveness of foliar‐applied potassium (K+, 1.25%) using different salts (KCl, KOH, K2CO3, KNO3, KH2PO4, and K2SO4) in ameliorating the inhibitory effect of salt stress on sunflower plants, a greenhouse experiment was conducted. Sodium chloride (150 mM) was applied through the rooting medium to 18 d–old plants and after 1 week of salt treatment; different K+‐containing salts were applied twice in 1‐week interval as a foliar spray. Salt stress adversely affected the growth, yield components, gas exchange, and water relations, and also caused nutrient imbalance in sunflower plants. However, foliar‐applied different sources of potassium improved shoot and root fresh and shoot dry weights, achene yield, 100‐achene weight, photosynthetic rate, transpiration rate, stomatal conductance, water‐use efficiency, relative water content, and leaf and root K+ concentrations of sunflower plants grown under saline conditions. Under nonsaline conditions, improvement in shoot fresh weight, achene yield, 100‐achene weight, photosynthetic and transpiration rates, and root Na+ concentration was observed due to foliar‐applied different K sources. Of the different salts, K2SO4, KH2PO4, KNO3, and K2CO3 were more effective than KCl and KOH in improving growth and some key physiological processes of sunflower plants. |
