Effect of increasing salinity on growth and mineral composition of wheat varieties and role of sodium exclusion capacity in salt tolerance mechanisms

A few wheat varieties including two Japanese wheat varieties were evaluated for their salt tolerance at seeding stage, their behavior to increasing salinity levels and role of Na exclusion capacity in salt tolerance mechanisms. The wheat varieties were grown in nutrient solution and subjected to 0 (control), 25,75 and 125 mM NaCl salinity levels for 7 days. Although the shoot growth was reduced while Na contents were increased progressively with increasing salinity in all varieties, the varieties were quite different in their response. Salt tolerant va rieties maintained less reduction in their root and shoot growth and better water relations in their shoots than salt sensitive varieties under saline conditions. The wheat varieties were quite different in their Na exclusion capacity. Poor growth in salt sensitive varieties might be due to higher accumulation of Na in their shoots resulting from low Na exclusion capacity of roots, higher Na transport to shoot and/or inferior compartmentation capability.