The Effects of Tea on Cadmium Accumulation
for the Emergent Accumulator Plant
Nasturtium officinale

The paddy soils have been contaminated by cadmium (Cd). To remedy the Cd-contaminated paddy soils, four tea types (black, green, white, and dark tea) were added to the Cd-contaminated paddy soils and planted the emergent accumulator plants Nasturtium officinale , and the effects of tea the Cd accumulation of N. officinale were studied. The green, white, and dark tea decreased the biomass of N. officinale , while the black tea had no effects. Compared with the control, the green, white, and dark teas decreased the root biomass by 12.73%, 8.18%, and 17.73%, respectively, and decreased the shoot biomass by 31.50%, 26.43%, and 33.08%, respectively. All four tea types decreased the chlorophyll a , chlorophyll b , and carotenoid contents in N. officinale . For antioxidant enzyme activity, the four tea types decreased N. officinale superoxide dismutase and peroxidase activities, while only the dark tea decreased the catalase activity. The four tea types had no effect on the shoot Cd content in N. officinale , and decreased the shoot Cd extraction due to decreased, or zero effects on the soil exchangeable Cd concentration. Therefore, tea cannot be used to improve the phytoextraction capacity of N. officinale for Cd-contaminated paddy soils.