Amelioration of salinity stress by NaCl pretreatment with reference to sugar metabolism in legumes Cajanas cajan L. and Vigna mungo L.

Abstract

The effect of salinity stress and its amelioration by pretreatment with low concentration of NaCl (50mM) on growth and sugar metabolism in arhar (cv. T120) and maskalai (cv. WBU109) seedlings were studied. Salinity was found to be more toxic for root growth than shoot growth. Fresh weight and dry weight of the seedlings gradually decreased with increasing concentrations of NaCl treatment. It was demonstrated that direct germination on NaCl solution increased both reducing sugar and non-reducing sugar contents while decreased the starch contents which were to some extent decreased by pretreatment of seeds with 50mM NaCl prior to germination in salt solutions. Salinity stress also affected the activites of different sugar metabolizing enzymes. The increase in the activities of starch phosphorylase, sucrose phosphate synthase, sucrose synthase and decrease in the activities of acid invertase were observed in directly salt treated test seedlings that were altered by pretreatment with sublethal concentration of NaCl in both the cultivars arhar (cv. T120) and maskalai (cv. WBU109) seeds. Thus the application of pretreatment by sublethal concentration of NaCl in both arhar (cv. T120) and maskalai (cv. WBU109) seeds exhibited significant alteration of all the partinent parameters tested under salinity stress and the effect of pretreatment in most of the parameters were more prominent in arhar (cv. T120) with compared to maskalai (cv. WBU109) seedlings.