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 Zn2þ.kg71 soil dry weight (SDW) (Zinc) or 50 mg Cd2þ.kg71 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. Zn2þ and Cd2þ exhibited contrasting distribution within tissues, indicating dissimilar handling by the plant. The main difference was the efficient compartmentalisation of Zn2þ in specific organ parts: old leaves and bark, while Cd2þ did not exhibit such a compartmentalisation. Results were also compared with a previous work where plants were exposed to 360 mg Cd2þ.kg71 SDW.