Pb and Zn Accumulation in a Cd-Hyperaccumulator (Viola Baoshanensis)

Abstract

Viola baoshanensis has been identified as a Cd-hyperaccumulator, however, its ability to accumulate Pb or Zn is less certain. Therefore, this study focused on determining whether or not V. baoshanensis can accumulate Pb or Zn, by means of field survey, hydroponic and pot experiments. In addition, we also tried to obtain further information on the Cd hyperaccumulating characteristics of this species. Under field conditions, V. baoshanensis accumulated on average 1090 mg Cd kg⁻¹, 1902 mg Pb kg⁻¹ and 3428 mg Zn kg⁻¹ in its shoots, respectively. In hydroponic and pot experiments, V. baoshanensis showed high tolerance to Cd, Pb, and Zn, as well as the ability to accumulate exceptionally high concentrations of the three elements in its shoots (>2% Cd, >1% Pb, and >0.5% Zn on a dry matter basis). These results, taken together, suggested that V. baoshanensis is not only a Cd-hyperaccumulator, but also a strong accumulator of Pb and Zn.

KEYWORDS:

• Phytoextraction
• hyperaccumulation
• heavy metal
• contaminated soil

ACKNOWLEDGMENTS

We sincerely thank professor Nick Dickinson in Liverpool John Moores University for his useful suggestions on our manuscript. This study was supported by the National “863” Project of China (No.2006AA06Z359 and 2007AA061001), the National Natural Science Foundation of China (No.30400053), and Team Work Project of the Natural Science Foundation of Guangdong Province (06202438).