Effect of Salinity and Osmotic Stresses on Some Economic Plants

The effect of water stress induced by NaCl or drought stress was studied on the leaves of wheat, barley, kidney bean and mung bean. After 25 days old, iso-osmotic stresses (200 mM) NaCl and PEG 6000 (180 g 1 ) were applied for 3 weeks old plants. Decreasing leaf dry weight was similar in -1 barley, kidney bean and mung bean under both stresses, while leaf dry weight of wheat decreased more under PEG stress than under NaCl stress. Water contents decreased in all plants under osmotic stress. 3 Ions K and NO contents decreased in relation to control under salt or osmotic stresses, whereas Na and + + ClG markedly increased in both wheat, barley and kidney bean. Amino acid increase was three times higher in leaves of kidney bean than in the leaves of all plants. However, the organic solutes and soluble sugar decreased in all plant leaves under both NaCl or drought stresses. Free proline increased under both stresses and its content was highest in wheat and in mung bean respectively under NaCl and PEG stresses. Malic acid accumulation was in wheat than in all plants under the PEG stress. The ability of plants to regulate their metabolic and physiological function could also play an important role under these harmful conditions.