Exogenous ascorbic acid or thiamine increases the resistance of sunflower and maize plants to salt stress

Abstract

Increasing NaCl levels retarded the net photosynthetic rate, biosynthesis of photosynthetic pigments and membrane integrity of maize and sunflower seedlings; a serious effect was exhibited when NaCl was applied at high concentration. On the other hand, the K + efflux increased at increasing NaCl levels. In addition, the various salt levels induced considerable variations in the concentrations of sodium, potassium, calcium and magnesium. The vitamins applied were generally effective in partially or completely countering the inhibitory effects of salt stress on net photosynthetic rate, pigments biosynthesis and membrane integrity, exerting a stimulatory action on these parameters, especially in plants subjected to moderate and low salinity levels. The leakage of K + was reduced by the application of both ascorbic acid (AsA) and thiamine (B 1 ). Soaking the seeds of salt-stressed plants in AsA or B 1 had a favourable effect on the accumulation of certain ions and antagonized or ameliorated the inhibitory effect of salt stress.