Antioxidative response to Cd in a newly discovered cadmium hyperaccumulator, Arabis paniculata F.

A hydroponic experiment was carried out to study the effect of cadmium (Cd) on growth, Cd accumulation, lipid peroxidation, reactive oxygen species (ROS) content and antioxidative enzymes in leaves and roots of Arabis paniculata F., a new Cd hyperaccumuator found in China. The results showed that 2289 mu M Cd in solution enhanced the growth of A. paniculata after three weeks, with 21-27% biomass increase compared to the control. Cd concentrations in shoots and roots increased with increasing Cd supply levels, and reached a maximum of 1662 and 8670 mg kg(-1) Cd dry weight at 178 mu M Cd treatment, respectively. In roots, 22-89 mu M Cd reduced the content of malondialdehyde (MDA), superoxide (O-2(-1)) and H2O2 as well as the activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and glutathione reductase (GR). In leaves, the contents of MDA, O-2(-1) and H2O2 remained unaffected by 22-89 mu M Cd, while 178 mu M Cd treatment significantly increased the MDA content, 69.5% higher than that of the control; generally, the activities of SOD, catalase (CAT), GPX and APX showed an increasing pattern with increasing Cd supply levels. Our present work concluded that A. paniculata has a great capability of Cd tolerance and accumulation. Moderate Cd treatment (22-89 mu M Cd) alleviated the oxidative stress in roots, while higher level of Cd addition (178 mu M) could cause an increasing generation of ROS, which was effectively scavenged by the antioxidative system. (c) 2008 Elsevier Ltd. All rights reserved.