Exogenous melatonin mitigates the salinity damages and improves the growth of pistachio under salinity stress

This study investigated the ability of exogenous melatonin (MT) to alleviate salinity stress in pistachio seedlings (Pistacia vera cv. Badami-Zarand) in a controlled greenhouse. Seedlings were treated with different salinity levels (25, 50, and 100 and 150 mM). Foliar application of melatonin with 0, 25, 50, 75, 100, 125 and 150 mu mol/L concentrations was applied two times during the seeding treated with the various salinity levels. The results indicated that the deleterious effects of MT application were observed when they were applied under non-stressful conditions (control). The greatest protective effect against simulated salinity stress was observed in 100 mu mol/L of MT in 150 mM salinity levels. Melatonins markedly alleviated the inhibitory effects of salinity on root and shoot growth, chlorophyll level and ion leakage. Activities of antioxidant enzymes, proline content, endogenous polyamine and melatonin increased with exogenous application of MT in salinity stress condition. Exogenous melatonin was also associated with significant increases in the nutrient uptake. Therefore, exogenous melatonin can attenuate the salinity damage via enhancing anti-oxidation ability, osmotic activity-adjusting, nutrient uptake and polyamines biosynthesis.