Uptake of Cadmium by Lemna minor, a (hyper?-) accumulator plant involved in phytoremediation applications

Metal pollution in waters and soils is a major environmental and human health problem. Cadmium (Cd2+) is a heavy metal displaying toxic effects in plants. In this work we studied the potentiality of Lemna minor, a monocotyledonous aquatic macrophyte, to phytoremediate cadmium-polluted waters. The plants were exposed to different cadmium concentrations 0, 13, 22 and 46?M CdSO4 for periods of 24, 48 and 72 hours. Relative growth rates (RGR), bioconcentration factor (BCF), tolerance index (Ti), cadmium uptake in whole plant and maximum efficiency of PSII (Fv/Fm) were measured under controlled climate conditions. RGR, Ti and Fv/Fm declined with increasing exposure time and cadmium concentrations, while the BCF and cadmium uptake showed an opposite behavior. Data analysis of RGR, BCF, Ti and Fv/Fm indicates that L. minor maintains a good capacity of growth, metal bioconcentration, tolerance and efficiency of PSII up to 48h in plants exposed to 13 and 22?M CdSO4. Our results exhibited that L. minor is a good cadmium accumulator and is able to remediate Cd-polluted waters, especially at low Cd concentrations.