Effect of arbuscular myccorhizal fungi on soil properties, mineral nutrition and antioxidant enzymes of olive plants under treated wastewater irrigation

Abstract

The present study aimed to determine the impact of arbuscular mycorrhizal fungi (AMF) on soil and young olive plants irrigated for one year with saline treated wastewater (TWW). One-year-old olive plants were inoculated with different AMF: (i) Glomus deserticola; (ii) Gigaspora margarita and (iii) combination of G. deserticola and G. margarita. Changes were observed in the soil chemical characteristics, in particular a significant increase in the electrical conductivity and an accumulation of Na+ and Cl−. Consequently, compared to the control treatment, the Na+ and Cl− contents of young olive plants irrigated with TWW increased by 12 and 133% in the leaves and by 98 and 106% in the roots, respectively. Moreover, an increase in the antioxidant enzyme activities, malondialdehyde and H2O2 contents, and electrolyte leakage rate was observed. Interestingly, roots and leaves of olive plants inoculated with AMF and irrigated with TWW showed a lower Na+ and Cl−content, and a higher macro- and micro-nutrient content, compared to uninoculated plants. The decrease of Na+ and Cl− contents in olive plants inoculated with both G. deserticola and G. margarita was about 24 and 43% in the leaves, and about 30 and 39% in the roots, respectively. Furthermore, the AMF symbiosis enhanced the antioxidant enzymes activities (CAT and APX) and reduced the malondialdehyde and H2O2 contents.