Bioaccumulation and ecophysiological responses to copper stress in two populations of Rumex dentatus L. from Cu contaminated and non-contaminated sites

Copper accumulation and ecophysiological responses to copper stress in two populations of Rumex dentatus L. were studied with pot culture experiments. Seeds of the two populations were respectively collected from Cu contaminated and non-contaminated sites. It was found that the copper accumulation and ecophysiological responses to Cu treatment between the two populations were significantly different. At high level of copper treatment, the activities of peroxidase and superoxide dismutase in the population from the contaminated site were significantly induced, while this was not the case for the population from the non-contaminated site. The chlorophyll content, electrolyte leakage and biomass were less affected in the population from the contaminated site than those in the population from the non-contaminated site. Compared to the population from the non-contaminated site, a lower copper content in the shoot was observed in the population from the contaminated site. These results indicate that the population from the Cu-contaminated site is more resistant to copper stress. The reason for this might be related to the fact that, in the contaminated site population, less Cu was absorbed and transported from the roots to shoots and higher peroxidase and superoxide dismutase activities induced in the plants when subjected to Cu stress. (C) 2004 Elsevier B.V. All rights reserved.