nutrient uptake and distribution in mycorrhizal pistachio seedlings under drought stress

this study was conducted to determine the effects of arbuscular mycorrhizal fungi (glomus mosseae and glomus intraradices) symbiosis on mineral uptake of two pistachio cultivars (pistacia vera cv. qazvini and pistacia vera cv. badami-riz-zarand) grown in the greenhouse under different drought stress levels. drought stress (ds) reduced the mycorrhizal colonization in both cultivars as well as nutrient uptake. the mycorrhizal plants had higher p, k, zn and mn concentrations than non-mycorrhizal plants regardless of soil moisture conditions while cu and fe concentrations were unchanged. distribution of elements was affected by amf treatments where all except p were accumulated more in leaves than in roots. contrastingly, under drought conditions, the absorbed elements tended to remain in root tissue. in the case of p and mn uptake, qazvini was superior in comparison with badami. in conclusion, it is suggested that amf inoculation improves drought tolerance of pistachio cultivars at least in part through the enhanced uptake of slowly diffusing mineral ions such as po42- and zn2+. moreover, arbuscular mycorrhizal (am) colonization provides better osmotic adjustment which can be correlated with k+ accumulation in top portions of inoculated plants. results of this study also emphasized that ‘qazvini’ cultivar may be more tolerant to drought than ‘badami’.