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

¹ University of Tuscia, Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Via San Camillo de Lellis, 01100 Viterbo, ITALY
² Institute of Agro-Environmental and Forest Biology (IBAF)- National Research Council (CNR) Via Salaria km 29.300, 00015 Monterotondo scalo. Rome ITALY
³ Institute for Water Research (IRSA), National Research Council (CNR), Via Salaria Km 29,300, 00015 Monterotondo Scalo ( Rome ) ITALY
⁴ Institute of Agricultural Biology and Biotechnology (IBBA) - National Research Council of Italy (CNR), Via Salaria km 29.300, 00015 Monterotondo Scalo. Rome ITALY

^a daniele.bianconi@ibaf.cnr.it
^b fabrizio.pietrini@ibaf.cnr.it
^c massacci@irsa.cnr.it
^d iannelli@ibba.cnr.it

Abstract

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 46μM 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 F_v/F_m declined with increasing exposure time and cadmium concentrations, while the BCF and cadmium uptake showed an opposite behavior. Data analysis of RGR, BCF, Tiand 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 22μM 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.