Growth and physiological activities of barley (Hordeum vulgare L. cv. Gustoe) grown in soil cultures were evaluated to recognize the ameliorative role of salicylic acid (SA) and KNO3 against the negative effects of salt and water deficit stresses. Barley plants were subjected to three levels of NaCl (50, 100 and 150 mM), three levels of water stress (80%, 70% and 50% of the soil water content (SWC) and the combination of 150 mM NaCl + 50 μM SA, 150 mM NaCl + 10 mM KNO3, 50% SWC + 50 μM SA and 50% SWC + 10 mM KNO3 for two weeks. Salt and water deficit stresses reduced the shoot growth, leaf photosynthetic pigments, K+ contents and provoked oxidative stress in leaves confirmed by considerable changes in soluble carbohydrate, proline, malondialdehyde (MDA), total phenolic compounds, antioxidant activity and Na+ contents. Leaf soluble protein of salt and water deficit treated plants was unaffected …