Activity of Antioxidant System Is Associated with Different Damages on Rice Seeds and Seedlings after Low Dose Heavy Ion Exposure

Dry seeds, water-soaked seeds and seedlings of rice were exposed to carbon ion radiation at doses of 0.02-20 Gy. Biological effects on survival, chromosomal aberrations and activity of protective enzymes against activated oxygen including superoxide dismutase (SOD) and catalase (CAT) as well as content of malondialdehyde (MDA) were detected. Oxidative damages were observed in both seeds and seedlings at dose as low as 0.02 Gy. Higher level of chromosomal damages and MDA were observed in seeds than in seedlings at doses lower than 2 Gy. The activity of SOD and CAT were significantly increased in seedlings at lower dose and decreased at higher dose. These results indicate that lower ability of antioxidant make non-growing seeds more sensitive to heavy ion induced damages than growing seedlings at low dose.