Effects of ECMF Isolated from Mining Areas on Water Status, Photosynthesis Capacity, and Lead Ion Transport of Populus alba Under Pb Stress

Abstract

Native ectomycorrhizal fungi (ECMF) are generally more effective than non-native ECMF in facilitating the phytoremediation of heavy metal (HM) ions from contaminated soils. This study aimed to investigate the contributions of four ECMF species—Suillus luteus, Suillus flavidus, Suillus variegatus, and Gomphidius glutinosus—that were isolated from mining areas to the growth, water status, photosynthesis, and metallothionein gene expression of Populus alba exposed to varying concentrations of lead (Pb). The experiment lasted two months and involved P. alba cuttings subjected to Pb concentrations of 0, 200, and 400 mg kg−1, representing no Pb stress, moderate Pb stress, and severe Pb stress, respectively. Results indicated that S. flavidus significantly enhanced the growth, water status, photosynthesis parameters, and metallothionein gene expression of P. alba under Pb stress, whereas S. luteus only exhibited positive effects under severe Pb stress. S. variegatus negatively affected the growth, water status, photosynthesis, and metallothionein gene expression of P. alba under Pb stress, while no significant difference was observed between the control treatment and G. glutinosus symbiosis. Therefore, S. flavidus and S. luteus are promising ECMF species for ecological restoration in mining areas, especially in P. alba woodlands.