Lead tolerance of Populus nigra in symbiosis with arbuscular mycorrhizal fungi in relation to physiological parameters

With the aim to examine lead tolerance of Populus nigra (clone 62/154) in symbiosis with arbuscular mycorrhizal fungi, a greenhouse experiment was carried out in a factorial randomized complete scheme with two factors 1) fungal inoculation in 4 levels (control, inoculation with Glomus mosseae, inoculation with G. intraradices and inoculation with G. mosseae G. intraradices) and 2) lead in 4 levels (0, 100, 500 and 1000 mg kg-1 soil). Mycorrhizal colonization and physiological parameters of plants were measured at the end of growth season. Results showed that at all Pb levels, the percentage of root mycorrhizal colonization in fungal treatments was significantly higher than that in control treatment (without fungal inoculation), however without significant differences between 3 fungal treatments. Pb treatments had no significant effect on root mycorrhizal colonization of P. nigra plants. Also, photosynthesis, stomatal conductance, transpiration, intercellular CO2 concentration and water use efficiency of P. nigra plants had no significant inhibitory effects versus the control found under Pb and fungal treatments or their interaction. The results of present study demonstrated that fungal treatments had no significant effects on physiological parameters and Pb tolerance of P. nigra plants. While, in relation to mycorrhizal colonization and physiological parameters, P. nigra clone 62/154 showed a good tolerance to Pb stress. So, in further investigations of phytoremediation of lead-contaminated soils, this clone can be considered as a proposed species.