In order to study the effectiveness of foliar-applied potassium (K+, 1,25%) using different salts (KNO3, KCl, K2SO4, K2CO3, KH2PO4 and KOH) in improving the inhibitory effect of salt stress on sunflower plants, a greenhouse experiment was conducted in Pakistan. Sodium chloride (150 mM) was applied through the rooting medium to 18-days old plants and after 1 week of salt treatment; amounts of 25 mM solution of K-source were applied twice with a 1-week interval as 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. Of the different salts, KNO3, K2SO4, K2CO3 and KH2PO4 were more effective than KCl and KOH in alleviating salt-induced inhibitory effects on sunflower plants. These more effective K sources improved the growth and some key physiological processes of sunflower plants.
Foliar applied potassium nitrate was effective in improving growth of salt-stressed sunflower plants
Saeed Akram, M., M. Ashraf, M. Shahbaz and N. Aisha Akram. 2009. Growth and photosynthesis of salt‐stressed sunflower (Helianthus annuus) plants as affected by foliar‐applied different potassium salts. Journal of Plant Nutrition and Soil Science, 172(6): 884-893.