Effects of Cadmium on Enzymatic and Non-Enzymatic Antioxidative Defences of Rice (Oryza Sativa L.)

Abstract

The effects of 60-d cadmium (Cd) exposure on enzymatic and non-enzymatic antioxidative system of Oryza sativa L. seedlings at tillering stage were studied using soil culture experiment. Research findings showed that chlorophyll content of Oryza sativa L. declined with the increase in soil metal concentration. Cd pollution induced the antioxidant stress by inducing O₂ ⁻¹ and H₂O₂, which increased in plants; at the same time, MDA as the final product of peroxidation of membrane lipids, accumulated in plant. The antioxidant enzyme system was initiated under the Cd exposure, i.e. almost all the activities of superoxide dismutase (SOD), peroxidase, catalase, glutathione peroxidase, and ascorbate peroxidase were elevated both in leaves and roots. The non-protein thiols including phytochelatins and glutathione to scavenge toxic free radicals caused by Cd stress was also studied. The contents of phytochelatins and glutathione were about 3.12–6.65-fold and 3.27–10.73-fold in leaves, against control; and the corresponding values were about 3.53–9.37-fold and 1.41–5.11-fold in roots, accordingly.

KEY WORDS:

• Oryza sativa L.
• antioxidant stress
• heavy metal
• plant growth
• phytophysiology

ACKNOWLEDGMENTS

This project was supported by the National Natural Science Foundation of China (No. 41161057); the Programs Foundation of Ministry of Education of Guangxi, China (No. 201010LX129); the Research funds of The Guangxi Key Laboratory of Environmental Engineering, Protection and Assessment; Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, China.