Distribution of Mineral Ions in Root and Leaf Tissues and Their Role in Salt Tolerance of Wheat Varieties under Saline Conditions

The distribution on Ca, K, Na and Cl in root and leaves was studied in salt tolerant variety (Chikugo Izumi) and salt sensitive variety (PB-81) of wheat under saline conditions. The plants grown in 5% Hoagland's nutrient solution were subjected to 100 mM NaCl salinity for one week before observation with scanning electron microscope and analysis of selected samples with X-ray microanalyzer. Root growth was not affected in salt tolerant variety but reduced significantly in salt sensitive variety. Shoot growth was reduced in both varieties but much higher in salt sensitive variety. Salinity increased accumulation of Na and Cl in all root cells including vascular cells in salt sensitive variety. Salt tolerant variety not only reduced uptake of Na and Cl under saline conditions but also restricted their accumulation in cortex maintaining vascular cells relatively free of these ions. Salt sensitive variety failed to block transport of Na and Cl from root to leaves leading to much accumulation of these ions in leaves under salinity sterss.