The effects of Cd stress on the growth and Cd accumulation of Bougainvillea spectabilis Willd. as an ornamental plant and the related mechanisms were investigated in the study. We studied the impact of Cd on the plant ultrastructure, examined the cellular distribution of Cd, explored the Cd chemical forms and transformation, and determined the organic acid secretion in the plants. The results showed that B. spectabilis could grow well in the Cd treatment groups, and the roots could accumulate high concentration of Cd. The soluble fraction (primarily in the vacuole) as the form of citrate in leaves of B. spectabilis was the major compartment for Cd storage. The citric acid secreted by B. spectabilis played an important role in the detoxification of Cd, as well as the growth of plants and Cd accumulation. As an ornamental plant, B. spectabilis has the potential to be used in the phytostabilization of Cd-contaminated soils and can beautify the environment at the same time.
Keywords: Bougainvillea spectabilis; Cd; Citric acid; Phytostabilization; subcellular distribution.