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 mu M CdSO4 for a period of 24, 48 and 72 hours. Relative growth rates (RGR), bioconcentration factor (BCF), tolerance index (T-i), cadmium uptake in whole plant and maximum efficiency of PSII (Fv/Fm) were measured under controlled climate conditions. RGR, T-i 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 F-V/F-M 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 mu 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.