Arbuscular Mycorrhiza Alters Metal Uptake and the Physio-biochemical Responses of Glycyrrhiza glabra in a Lead Contaminated Soil

Arbuscular mycorrhizal (AM) fungi can affect the host's ability to cope with several environmental stresses, such as heavy metal stress. Therefore, an experiment was conducted to assess the effect of the Funneliformis mosseae inoculation on growth and physio-biochemical parameters and lead (Pb) accumulation in liquorice (Glycyrrhiza glabra L.) under Pb stress. A factorial experiment was performed with the combination of two factors, fungi (inoculated and non-inoculated (NM)) and soil Pb levels (0, 150, 300, and 450 mg kg^-1 soil) with four replicates. In the presence of Pb, symbiosis with F. mosseae exert positive effect on growth parameters, which was more significant in shoots than roots. Mycorrhization improved fresh and dry weights and length in shoot by 147, 112.5 and 83%, respectively, compared to NM plants at Pb150 level. Moreover, F. mosseae significantly increased tolerance index and the concentrations of soluble sugars and flavonoids in shoots and proline, phosphorus, potassium, calcium, zinc and manganese in shoots and roots but decreased their malondialdehyde concentrations under Pb stress. The Pb concentrations, transfer and bioaccumulation factors of mycorrhizal plants were less than non-mycorrhizal ones. A positive correlation was also observed between glomalin secretion and colonization rate in Pb treated soils. These results indicate the importance of mycorrhizal colonization in alleviating the Pb-induced stress in liquorice, mainly through improving the nutrition, modifying reactive oxygen species detoxifying metabolites and reducing the translocation of Pb to shoots. Observations revealed that mycorrhization of liquorice would be an efficient strategy to use in the phytoremediation practices of Pb-contaminated soils.