EXPERIMENT WITH EFFECT OF CADMIUM ON ACTIVITY OF SUPEROXIDE DISMUTASE IN GILL AND LIVER TISSUE OF CRUCIAN
YANG Li hua, FANG Zhan qiang, ZHENG Wen biao, WU Yu yuan, MA Guang zhi (College of Life Science, South China Normal University, Guangzhou 510631, China)
This paper presents an experiment the author has done with the crucian when it was exposed to cadmium to test the influence of the cadmium polluted sludge on the fish activities. With crucian exposed to cadmium (CdCl 2·2.5H 2O) with 0 mg/L, 0.73 mg/L, 1.46 mg/L, 2.95 mg/L for 6 days, the authors intend to determine the activities of superoxide dismutase (SOD) of gill and liver tissues in 144 h by means of improved pyrogallol autoxidation. The results of the experiment indicate that the activities of SOD in gill and liver haven't made any obvious change at low Cd concentrations in a short time. The activities of SOD, however, would increase with the exposure time going on, which may probably come about as a result of the "Toxic excitement effect". With the high concentration Cd inhibiting the activities of SOD in gill and liver, the inhibiting strength will increase with the prolonging of the exposure time and the concentration enhancing. Thus, it suggests that the harm caused by active oxygen due to the decrease of the activities of SOD is an important reason that leads to the mass death of crucian exposed to Cd. The experiment also indicates that the activities and sensitivities to Cd of SOD in liver are higher than those in gill, which may be associated with their physiological functions.