Potassium synergize the positive effect of ascorbic acid on some morpho-physiological parameters of salt stressed faba bean cultivars

Abstract

THIS WORK was undertaken to evaluate the effect of ascorbic acid (AsA) and potassium (K) on some morpho-physiological parameters of two Vicia faba L cultivars (Giza 843 and Giza 716) grown in nutrient solutions containing different concentrations of NaCl (50, 100 and 150mM NaCl) and K (5, 10 and 15mM) for two weeks. In general, under saline conditions, significant reduction in plant biomass and chlorophylls was detected. Seed presoaking in AsA solution resulted in massive increase in growth parameters and chlorophyll contents in both genotypes of stressed and non-stressed plants, but it depended on K concentration, 15mM K was the best. The positive effect of AsA on growth of salt stressed plants was not manifested when K concentration was low (5mM). In both genotypes, carbohydrate and protein contents increased as NaCl increased. Further significant-increase in their contents was detected when seeds were soaked in AsA and plants were cultured under salt stress; it depended on K concentration in the nutrient solution, 15mM K was the best. This type of synergizing between AsA and K on carbohydrate and protein contents was absent under low concentration of K. Sodium increased but K, Mg and Ca contents decreased in both cultivars under salt stress especially when K concentration was low (5mM). Under stressed or unstressed conditions, significant decrease in Na but significant increase in K, Ca and Mg contents due to AsA was detected and it was proportional to K concentration, 15mM K was the best.