Beneficial effect of mycorrhiza on nutritional uptake and oxidative balance in pistachio (Pistacia spp.) rootstocks submitted to drought and salinity stress

Abstract

Environmentally-friendly management techniques such as arbuscular mycorrhizal fungi (AMF) strategies are urgently required to improve plant nutrition and overcome abiotic stress. In this study, we evaluated the influence of symbiotic AMF on four pistachio rootstocks subjected to drought (100 % as the control, and 80 %, 60 %, and 40 % of field capacity as the treatments) and salinity (0.91 as the control, and 7.57, 16.12, and 24.63 dS/m using NaCl as the treatments) stress for 60 days in two separate experiments. Under both drought and salinity stress conditions, the root and shoot dry weights of the pistachio rootstocks markedly increased in the AMF-inoculated plants (+M). The accumulation of minerals in the leaves and roots of (+M) plants was significantly higher than in the non-inoculated plants (-M). AMF improved the nutritional status (N, P, Mg2+, and Ca2+) of the genotypes under both stress conditions. Mycorrhizal association significantly decreased Na+ and Cl− concentrations in the leaves and roots of the pistachio rootstocks under salinity stress. In (+M) plants under drought stress, hydrogen peroxide (H2O2) and methylglyoxal (MG) concentrations in leaf and root tissues and malondialdehyde (MDA) in the roots, and under salinity stress, the H2O2 and MG concentrations in the leaves and MDA in both tissues were lower than those in the (-M) plants. The Sarakhs rootstock under salinity stress accumulated lower minerals (N, P, K+, and Ca2+) and more antioxidants than the other rootstocks, which could be due to its higher sensitivity to this stress. Both stresses reduced the chlorophyll concentration and increased the oxidant content and electrolyte leakage from the roots and leaves of the rootstocks. Sarakhs rootstock under drought stress and Badami-Riz–e-Zarand and UCB1 rootstocks under salinity stress behaved better in terms of mineral absorption. Thus, they were more tolerant of drought and salinity stress, respectively. Based on these findings, the association of mycorrhizal fungi and pistachio rootstocks is a sustainable strategy for increasing biomass, mineral, and Chl contents, and decreasing oxidant content, thereby enhancing the stress tolerance of plants.