ALLEVIATION OF SALT STRESS IN PISTACHIO (Pistacia vera L.) SEEDLINGS INOCULATED WITH ARBUSCULAR MYCORRHIZA FUNGI

Soil salinity is a worldwide problem especially in arid and semiarid regions because it adversely affects growth of plant. Arbuscular mycorrhizal (AM) symbiosis can alleviate plants salt stress. The effects of salinity on pistachio plant growth, pigment concentration, nutrient acquisition, and accumulation of osmolytes and activities of antioxidant enzymes were investigated in this research. Four different salt concentrations (0, 75, 150, and 300 mM NaCl) were applied to mycorrhizal (+AM) and non-mycorrhizal (-AM) plants, and their effects were analyzed. The experiment was carried out in Islamic Azad University greenhouse (Damghan, Iran). The experiments comprised of 4×2 factorial in a completely randomised design. Mycorrhizal colonization significantly enhanced plant growth, biomass, and pigment concentration under saline and nonsaline conditions. Salt stress decreased P, K, N, and Ca concentrations, but it increased Na in pistachio plants. These nutrient contents (except Na content) were higher in +AM than -AM plants in salt stress. The concentrations of organic solutes, including soluble sugars, proline, and glycinebetaine in pistachio plants, increased under saline conditions, whereas the concentration of soluble protein decreased. AMF may protect plants against salinity by altering the activities of antioxidant enzyme, adjusting osmotic and nutrient acquisition, and affecting physiology.