Cunninghamia lanceolata (Lambert) Hooker: A Promising Candidate for Phytoremediation of Cd-Contaminated Soils

Cadmium (Cd) is one of the most common toxic heavy metal elements in soil pollution, which can be continuously enriched in the food chain and eventually threaten human health. Phytoremediation, which is using plants to transfer heavy metal elements from soils, is a promising solution for the remediation of heavy metal-contaminated soils. In this study, we evaluated whether Cunninghamia lanceolata (Lambert) Hooker (Chinese fir), a widely planted timber tree worldwide, had the potential to remediate Cd-contaminated soils through 90 days pot of experiments with different Cd concentration soils (0, 5, 10, 20, 50, 100 mg kg(-1)). C. lanceolata did not show obvious toxic symptoms in Cd-contaminated soils, although Cd inhibited plant growth and decreased net photosynthetic rate slightly. The activities of antioxidant enzymes increased significantly under Cd stress, indicating that C. lanceolata had a strong self-regulation ability and can tolerate Cd stress. The Cd bioconcentration factor (Cd concentration in plant divided by Cd concentration in soil) of C. lanceolata were greater than 1 at all Cd concentrations, indicating that C. lanceolata had a strong ability to absorb Cd, although Cd was mainly accumulated in roots. Our results indicated that C. lanceolata had a strong tolerance and phytostabilization ability of Cd. Considering the wide distribution worldwide, large biomass, and rapid growth of C. lanceolata, it could be a promising candidate for phytoremediation of Cd-contaminated soils.