Cadmium accumulation in Atriplex halimus subsp schweinfurthii and its influence on growth, proline, root hydraulic conductivity and nutrient uptake

Atriplex halimus subsp. schweinfurthii is a newly found cadmium (Cd)-hyperaccumulator, but there have been no detailed studies on its physiological responses when Cd is hyperaccumulated. A. halimus was grown in hydroponic conditions to investigate the effect of cadmium chloride (CdCl2) on growth, water status, leaf chlorophyll concentration, proline and Cd accumulation. Treatments were prepared by adding 0, 50, 100, 200 and 400 mu M CdCl2 to the nutrient medium. Plant growth was significantly affected at high-Cd treatments. Increased CdCl2 decreased chlorophyll concentration, transpiration and root hydraulic conductivity (L-0). Hence water flux had only a little effect on the uptake of Cd in A. halimus seedlings. In contrast, proline content increased with increasing CdCl2 concentration. Plants accumulated substantial amount of Cd in different plant parts (shoot and root). Most of the Cd taken up was retained in roots (606.51 mu g g(-1) DW after 15 d at 400 mu M CdCl2). The addition of Cd in the culture medium affected calcium (Ca) and potassium (K) nutrition in both shoot and root. A. halimus provides a new plant resource for exploring the mechanism of Cd hyperaccumulation and has potential for use in the phytostabilization of Cd-contaminated salt soils. (C) 2008 Elsevier GmbH. All rights reserved.