Cadmium and Zinc are differentially distributed in Populus tremula x P. alba exposed to metal excess

Abstract

Poplar plants were exposed during 61 days to a soil added with heavy metals so as to contain 300 mg Zn²⁺.kg⁻¹ soil dry weight (SDW) (Zinc) or 50 mg Cd²⁺.kg⁻¹ SDW (Cadmium). The Cd treatment induced a delayed growth of poplar, whereas Zn induced no change in physiological parameters. Both treatments resulted in a significant metal accumulation in plants. Zn²⁺ and Cd²⁺ exhibited contrasting distribution within tissues, indicating dissimilar handling by the plant. The main difference was the efficient compartmentalisation of Zn²⁺ in specific organ parts: old leaves and bark, while Cd²⁺ did not exhibit such a compartmentalisation. Results were also compared with a previous work where plants were exposed to 360 mg Cd²⁺.kg⁻¹ SDW.

Keywords:

• Poplar
• heavy metal
• cadmium
• zinc

Acknowledgements

The authors are grateful to Vanessa Caruso for the correction of the English version. Thomas Durand was supported by a PhD fellowship of the Luxembourg Ministry of Culture, Higher Education and Research (BFR 05/094). The authors are also grateful to Alain Guichard, Gilles Moreau and Julie Jumeau (Laboratoire de Biologie des Ligneux et des Grandes Cultures) for their excellent technical assistance.