While seedlings of Radish raised in increasing contents of Cd2+ in hydroponic system, increment in ratio of superoxide dismutase (SOD)/catalase (CAT) and levels of superoxide anion (O2 .-) and lipid peroxides was observed; 125 μmol·L-1 Cd2+ treatment resulted in a gradual elevation in SOD activity; while at Cd2+ level of 250 and 500 μmol·L-1 SOD activity considerably increased at first, then declined to even lower than that of the control. CAT activity showed enhancement in leaves whereas decrease in roots. Cd2+ induced an obvious elevation...
