Interactive effects of ascorbic acid and salinity stress on the growth and photosynthetic capacity of pistachio (Pistacia vera L.) seedlings

Abstract

SummaryAscorbic acid (AA) is one of the most important and abundant water-soluble anti-oxidants in plants and is responsible for inducing tolerance to a number of biotic and abiotic stresses. An experiment was conducted to test whether two exogenous applications of AA as foliar sprays (7 d apart at 20 ml plant-1) at various concentrations (0, 0.1, 0.5, or 1.0 mM) would protect pistachio (Pistacia vera L.) seedlings subjected to salt stress (0, 30, 60, or 90 mM NaCl). Ascorbate improved the growth rate of pistachio seedlings grown under salt stress and increased their relative contents of leaf chlorophyll and photosynthetic capacity compared to AA-untreated control seedlings after 100 d of salt stress. Ascorbic acid ameliorated the damage caused by salt stress by inhibiting increases in leaf proline concentration and in electrolyte leakage from leaf cells. The greatest ameliorative effect of AA was observed when pistachio seedlings were sprayed at 0.5 or 1.0 mM AA. These results indicate that applying two foliar sprays of 0.5 – 1.0 mM AA, 7 d apart, can reduce the harmful effects of salinity and increase resistance to salt stress in pistachio seedlings.