Improving salt tolerance by exogenous application of salicylic acid in seedlings of pistachio

Salicylic acid (SA) is a common, plant-produced signal molecule that is responsible for inducing tolerance to a number of biotic and abiotic stresses. An experiment was therefore conducted to test whether the application of SA at various concentrations (0, 0.10, 0.50, or 1.00 mM) as a foliar spray would protect pistachio (Pistacia vera L.) seedlings subjected to salt stress (0, 30, 60, or 90 mM NaCl). SA improved growth rate of pistachio seedlings under salt stress and increased relative leaf chlorophyll content, relative water content, chlorophyll fluorescence ratio, and photosynthetic capacity as compared with the control at the end of salt stress. SA ameliorated the salt stress injuries by inhibiting increases in proline content and leaf electrolyte leakage. It appeared the best ameliorative remedies of SA obtained when pistachio seedlings were sprayed at 0.50 and 1.00 mM.