Reactive oxygen species metabolism during the cadmium hyperaccumulationof a new hyperaccumulator Sedum alfredii (Crassulaceae)
ZHANG Zhong-chun , QIU Bao-sheng
DOI:
Received February 05, 2007,Revised May 17, 2007, Accepted , Available online
Volume 19,2007,Pages 1311-1317
- Summary
- References
- Related Articles
Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation of Cd polluted
sites. Malondialdehyde (MDA), reactive oxygen species (ROS) and antioxidases (catalase (CAT); superoxide dismutase (SOD);
peroxidase (POD)) in the leaf were determined when S. alfredii was treated for 15 d with various CdCl2 concentrations ranging from 0 to
800 mol/L. The results showed that the production rate of 20,70-dichlorofluorescein (DCF), which is an indicator of ROS level, reached
up to the maximum at 400 mol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MDA accumulation tended
to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOD activity was sharply suppressed at 800
mol/L CdCl2. However, the enhancement of POD activity was observed when CdCl2 concentration was higher than 400 mol/L. In
addition, its activity increased when treated with 600 mol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger,
was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to
decline with the increase of sodium benzoate concentration. It came to the conclusions that POD played an important role during Cd
hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation.
