Effect of arbuscular mycorrhizal fungi inoculation on growth and physiology performance of olive tree under regulated deficit irrigation and partial rootzone drying

Abstract

[eng] Olive ( Olea europaea L., cv Picholine marocaine) trees were grown with (myc+) or without (myc-) Rhizophagus irregularis in split-root pots, and subjected to three irrigation methods: full irrigation (Control), partial root-zone drying (PRD) and regulated deficit irrigation (RDI). Stomatal conductance, leaf relative water content, vegetative growth (Shoot length, total leaf area and leaf number), proline, sugar content and leaf carbon isotope discrimination (13C) were measured in order to evaluate the influence of arbuscular mycorrhizal (AM) symbiosis on the tolerance of olive to drought. The low soil moisture under PRD and RDI treatments had a negative effect on all studied parameters. However, the olive plants inoculated with the AM fungi generally had significantly greater growth indices in comparison to the non-inoculated ones. Also, at physiological (gs and RWC) and biochemical (proline, sugar and 13C) level, myc+ plants exhibited better performance under drought in comparison with myc- ones. These responses were in the most time, earlier under PRD treatment. Arbuscular mycorrhizal fungi can tolerate better the water deficit stress of RDI and PRD treatments saving 50% of the irrigation water.