Lipid peroxidation and activity of some antioxidative enzymes in the root of maize (Zea mays) cultivated on cadmium contamination soil
In this study, we examined the tolerance capacity of Zea mays to cadmium pollution. Soil was treated with varied concentrations of Cadmium; 5 mg, 10 mg, 20 mg and 30 mg/kg soil and Zea mays planted. Root samples were collected in weeks 3, 4, 5 and 6. Activities of Peroxidase, catalase superoxide dismutase, and lipid peroxidation were investigated. Decrease in peroxidase activity was extremely significant (p <0.05) in weeks 4 and 5 while that of week 6 was not significantly (p > 0.05) different from normal. The decrease correlated with increase in Cadmium concentration. However, at the highest concentration of 30 mg/kg of soil the trend was not significant. Increase in the activity of catalase was recorded in weeks 3 and 6. This increase didn’t follow a particular trend but at higher concentration of Cd and long term exposure, it became apparent. There was a negative correlation between catalase activity and lipid peroxidation. In week 3, catalase activity was not significant (p > 0.05) and lipid peroxidation was significant (p < 0.05) while at week 4, catalase activity was significant (p < 0.05) and lipid peroxidation was not significant (p = 0.8432). Catalase activity was not significant (p = 0.2753) at week 5 and lipid peroxidation was significant (p = 0.0030). At week 6 when catalase activity became extremely significant (p < 0.05), lipid peroxidation had a p value of 0.0128. Generally no significant activity (p > 0.05) was observed for superoxide dismutase. A significant increase in absorption of cadmium (p = 0.0374) at 30mg/kg soil was observed between weeks 5 and 6. It was also observed that cadmium had no significant effect (p > 0.05) on the root weight during the period of study. It’s suggestive therefore Cadmium
contamination of soil could affect growth of maize and induce oxidative stress.