The influence of sodium chloride salinity on the growth and mineral nutrition of horsegram, Dolichos biflorus L.

Abstract

Dolichos biflorus plants were grown in sand culture in the presence of five levels of sodium chloride ranging from 25 to 150 mM. The plant was found to possess a good salt tolerance capacity since a general decline in growth was evident only above NaCI concentration of 75 mM. Salt concentrations above 100 mM reduced the yield in terms of average pod number. The analysis of inorganic constituents revealed marked alterations in the mineral nutrition of the plant under saline conditions. Salt stress caused accumulation of sodium in all plant parts although it was more prenounced in roots and stem. The leaves accumulated large amounts of chlorides under saline conditions. The potassium content in the roots and stem markedly decreased due to salinity. The leaves retained a high potassium level up to 50 mM NaCl treatment. Salt stress caused an increase in the calcium content in leaves and roots. The accumulation of phosphorus and magnesium in different plant parts was favoured by salt stress. A reduction in the manganese content in salt stressed leaves was noticed while higher doses of salinity favoured iron accumulation in different plant parts. A possible involvement of these alterations in the salt tolerance behaviour of the plant is discussed.