Cadmium tolerance and accumulation characteristics of Siegesbeckia orientalis L.

Identification of new higher yield cadmium (Cd)-hyperaccumulating cultivars from native species is key to the phytoremediation of Cd contaminated soils. A pot experiment with different soil Cd concentrations and a plot experiment at 28.44 mg Cd kg−1 were conducted to investigate Cd tolerance and accumulation by Siegesbeckia orientalis following a field survey. In the pot experiment, at Cd concentration of 150 mg kg−1, S. orientalis grew normally and shoot biomass was not reduced significantly compared with the no Cd control. The activities of superoxide dismutase and catalase in roots and leaves, and peroxidase in leaves significantly increased with increasing soil Cd (P < 0.05). The highest shoot Cd concentrations were 117.48, 192.92 and 77.10 mg kg−1, in the field survey, pot and plot experiments, respectively and their corresponding accumulations were 6.762 mg plant−1, 4.134 mg pot−1 and 18.45 mg m−2. All Cd bioconcentration factors and translocation factors were more than 1.0. Therefore, S. orientalis is a Cd-accumulator with hyperaccumulating ability.