Effects of Combined Pollution of Pb and Cd on the Growth and Element Uptake of Acacia confusa

A pot experiment was conducted to study the effects of Pb-Cd combined pollution on the growth, root morphology, nutrient and heavy metal element absorption of Acacia confusa. The results showed that the plant height of A. confusa under Pb 1500 mg/kg, Cd 25 mg/kg and Pb 1500 mg/kg, Cd 50 mg/kg conditions was inhibited, and decreased by 30.15% and 34.23% respectively compared with that of the control. The ground diameter growth was not significantly affected by the pollution. The biomass of roots, stems, leaves, total biomass and root length under combined contamination conditions were suppressed, the average root diameter was promoted, while the root volume was not significantly affected. Among the nutrient elements(N, P, K) in all parts of the plant, only the N element of roots were significantly promoted by the treatment of Pb 1500 mg/kg, Cd 50 mg/kg, which was 42.00% higher than CK. The content of Pb and Cd in roots, stems and leaves of A. confusa were significantly promoted by Pb-Cd combined contamination. The root Pb content increased at first, and then decreased with increasing concentration of contamination, and reached a significant maximum(289 mg/kg) under the treatment of Pb 1500 mg/kg, Cd 25 mg/kg. The content of Pb in leaves and Cd in roots increased significantly with the increase of pollution concentration. A. confusa has strong resistance and certain absorptive capacity to Pb and Cd, and can resist combined contamination through root nodules and altering root morphology. A. confusa has application potential in the ecological restoration of low and medium concentration of Pb-Cd contaminated soil.