Cadmium Removal by the Hydroponic Culture of Giant Reed (Arundo donax) and Its Concentration in the Plant

Abstract

Giant reed has high biomass productivity, and is a promising plant to be used for a constructed wetland system in which energy/material production and water purification are achieved simultaneously (multi-functional wetland). In this study, the cadmium removal by hydroponically cultured giant reed was observed, and its concentration in the plant body was measured to clarify the applicability of the wetland for cadmium treatment. The results suggested that the hydroponic culture of giant reed has high potential for cadmium removal. In addition, the inhibitory effect of cadmium on phosphorus removal, that is also important for water purification, was not observed under a concentration lower than 1 mg-Cd/L for 7 days. After about 2 months of hydroponic culture the absorbed cadmium was highly concentrated in the rhizome. Furthermore, the positive correlation between glutathione (GSH) in the rhizome and cadmium removal rate was observed, indicating that the production of GSH was controlled by the cadmium assimilated in the giant reed.