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  • Cadmium tolerance and hyper...
    Yang, X.E; Long, X.X; Ye, H.B; He, Z.L; Calvert, D.V; Stoffella, P.J

    Plant and soil, 02/2004, Letnik: 259, Številka: 1-2
    Journal Article

    Sedum alfredii Hance has been identified as a new zinc (Zn) hyperaccumulating plant species. In this study, the effects of cadmium (Cd) supply levels (control, 12.5, 25, 50, 100, 200, 400, 800 μmol Cd L-1) on the growth and cadmium accumulation and Zn supply on Cd accumulation in S. alfredii Hance were studied. The results showed that no reduction in shoot and root dry matter yields were noted when the plants were grown at Cd supply levels up to 200 μmol L-1 in nutrient solution. Slight stimulation on shoot growth was noted at relatively low Cd levels (25 to 100 μmol L-1). Cadmium concentrations in leaves and stems increased with increasing Cd supply levels, and reached a maximum of approximately 9000 and 6500 mg kg-1 (DW) at 400 μmol Cd L-1, respectively. Root Cd concentration increased sharply only at relatively high Cd levels. Cadmium distribution in different parts of the plant was in the order: leaf > stem >> root. The amount of Cd accumulated in the shoots reached 2.9 and 3.2 mg plant-1 at external Cd levels of 200 and 400 μmol L-1, respectively. The shoot/root Cd ratios were greater than 2 and more than 95% of the total Cd taken up by S. alfredii was translocated to the shoots at the external Cd levels ≤200 μmol L-1. The concentrations of P, Ca, Mg, B, Fe, Mn, Cu, and in the shoots and roots were influenced differentially by Cd treatments. High Zn supply (500 μmol L-1) enhanced Cd concentrations in the leaves and stems at the Cd levels ≤100 μmol L-1, and root Cd concentration at the Cd levels ≤50 μmol L-1. These results indicate that S. alfredii has an extraordinary ability to tolerate and hyperaccumulate Cd and this is the first report of the new Cd hyperaccumulator S. alfredii Hance. The finding of Cd/Zn hyperaccumulation in S. alfredii Hance provides an important plant material for understanding the mechanisms of Cd/Zn co-hyperaccumulation and for phytoremediation of the heavy metal contaminated soils.