Effect of enhanced UV-B radiation and low-energy N~+ ion beam radiation on the response of photosynthesis, antioxidant enzymes, and lipid peroxidation in rice (Oryza sativa) seedlings

摘要

To understand the effect of enhanced UV-B radiation and low-energy N ~+ ion beam radiation on the response of photosynthesis, antioxidant enzymes, and lipid peroxidation in rice seedlings, Oryza sativa was exposed to three different doses of low-energy N~+ ion beam and enhanced UV-B alone and in combination. Enhanced UV-B caused a marked decline in some photosynthetic parameters (net photosynthetic rate, transpiration rate, and stomatal conductance) and photosynthetic pigments, whereas it induced an increase in hydrogen peroxide (H_2O_2) accumulation, the rate of superoxide radical production, and the content of malondialdehyde (MDA). Enhanced UV-B also induced an increase in the activity of antioxidant enzymes (superoxide dismutase [SOD], peroxidase (POD), and catalase [CAT]) and some nonenzymatic antioxidants such as proline. Under the combined treatment of enhanced UV-B and low-energy N~+ ion beam at the dose of 3.0 × 10~(17) N~+ cm~(-2), the activity of antioxidant compounds (SOD, POD, CAT, proline, and glutathione), photosynthetic pigments, and some photosynthetic parameters (net photosynthetic rate, transpiration rate, and stomatal conductance) increased significantly; however, the MDA content, H_2O_2 accumulation, and rate of superoxide radical production showed a remarkable decrease compared with the enhanced UV-B treatment alone. These results implied that the appropriate dose of low-energy N~+ ion beam treatment may alleviate the damage caused by the enhanced UV-B radiation on rice.