EFFECTS OF UV-B RADIATION ON PHOTOSYNTHESIS AND CHLOROPLAST FUNCTION OF PLANT LEAVES

Strong UV-B radiation can harm land plants, destroy plant photosynthesis and reduce crop yields. In this paper, the effects of UV-B radiation on wheat leaf photosynthesis and chloroplast function have been systematically studied. The results of the study showed that the effects of different intensities of UV-B radiation on the growth of wheat seedlings are obvious. Under the condition of strong UV-B radiation, the leaf color of wheat leaves becomes lighter, showing grayish green, the surface area of the leaves is reduced, and the edge of the leaves curls. Moreover, UV-B radiation has a significant effect on the amount of wheat root coefficient, root length, root volume and plant height. The enhancement of UV-B radiation inhibits photosynthesis, leading to plant growth inhibition, thereby reducing organic nutrients transported to the root system. When the UV-B radiation intensity is greater than 60 mg/g, the damage to the leaves is significantly increased. The damaging effect of UV-B radiation on chlorophyll a is significantly greater than that on chlorophyll b. When the UV-B radiation intensity is 30 mu W.cm(-2), its damage to chlorophyll is not obvious; with the increase of radiation intensity, when the UV-B intensity is between 60 mu W.cm(-2) and 120 mu W.cm(-2), its destructive effect on chlorophyll has reached a significant level. UV-B radiation also has a significant effect on the activities of SOD and POD enzymes in wheat seedlings. This research has important guiding significance for further understanding of the adaptability of wheat to UV-B radiation and the damage mechanism of UV-B to plant photosynthesis.