Protective Role of Arginine Against Oxidative Damage Induced by Osmotic Stress in Ajwain (Trachyspermum ammi) Seedlings Under Hydroponic Culture

Assessing the tolerance of medicinal plants is important for planting them in drought areas. Arginine is a growth regulator and its role in plants’ tolerance to environmental stresses such as drought has been investigated. To evaluate the protective effects of arginine against osmotic stress induced by polyethylene glycol in ajwain (Trachyspermum ammi) seedlings, an experiment was conducted as a completely randomized design in a factorial arrangement with three replicates. Experimental treatments included arginine at three levels (0, 10 and 20 µM) and osmotic stress (induced by polyethylene glycol 6000) at three levels (0, 13.5% and 17% (W/V)). Results showed that arginine application through the root medium caused the reduction of H2O2 content, lipid peroxidation (malondialdehyde and other aldehydes) and lipoxygenases activity and increased the antioxidant enzymes activity (calatase, ascorbate peroxidase and guaiacol peroxidase), protein content and proline content under osmotic stress. Therefore, it seems that the application of arginine greatly improves the dehydration tolerance through elevated activities of antioxidant enzymes.