Mercury stress resistances in Nauclea orientalis seedlings inoculated with arbuscular mycorrhizal fungi

摘要

The effect of inoculation with the arbuscular mycorrhizal (AM) fungi on the resistance of mercury (Hg) in lonkida (Nauclea orientalis) seedlings were investigated using an artificially contaminated river sand media at the concentration of 0, 375 and 750 μM Hg at screen house. Mercury accumulation was lower in mycorrhizal roots than in non-mycorrhizal roots when Hg was added at the rates of 750 μM. However, Hg accumulation and its translocation to the leaves were very low, either in mycorrhizal or non-mycorrhizal seedlings. The amount of Hg retained in roots was higher than in leaves, irrespective of applying different Hg concentration. N. orientalis seedlings have a high tolerance to Hg (> 70%). Under these experimental conditions, N. orientalis shows a high resistance and capacity to retain Hg in roots. Mycorrhizal symbiosis showed a significant effect of the resistance to Hg of N. orientalis plants grown in Hg-polluted and Hg-unpolluted media. Furthermore, the beneficial effects of the AM fungi observed in this study aroused an interest in considering the role of AM fungi in plant-based strategies of remediation of highly Hg-polluted soils.