Effects of Enhanced UV-B Radiation on δ13C Values and Physiological Feature in Tobacco Leaves Effects of NaHSO3 on Photosynthesis in Spinach Seedlings Under EnhancedUV-B Radiation Effects of NaHSO3 on Photosynthesis in Spinach Seedlings Under EnhancedUV-B Radiation Effects of elevated O3 concentration and UV-B radiation on the chlorophyll content and active oxygen metabolism of soybean leaves.