中文摘要：

用水培法研究Ce（Ⅲ）对紫外辐射（UV—B，280—320nm）胁迫下油菜幼苗光合色素含量与希尔反应活性变化对光合作用的影响。静态数据表明，20mg·L^-1CeCl3能有效减缓紫外辐射（T1／0．15W·m^-2和T2/45W·m^-2）胁迫所导致的光合速率下降，叶绿素与类胡萝卜素含量减少及Hill反应活性降低，使得Ce＋UV—B组各项指标虽低于CK，但明显优于UV—B组。动态曲线显示，Ce减缓了UV—B胁迫期各项指标的下降趋势，加快恢复期的上升速度，且最终达到较好的恢复效果。通过对Chl含量、Hill反应活性与Pn的相关统计学分析发现，Ce对UV—B辐射胁迫下Hill反应活性和叶绿素含量的调节具有改善光合功能的作用，且对Hill反应活性的调节作用大于叶绿素含量。

英文摘要：

Effect of cerium （Ce^3＋） on photosynthesis rate, photosynthetic pigments content and Hill reaction activity in soybean seedlings exposed to two levels of uhraviolet-B radiation （UV-B, 280-320 nm） was studied with hydroponics under laboratory conditions. The results showed that UV-B radiation caused the decrease in photosynthesis rate, chlorophyll and carotenoid content, as well as Hill reaction activity. CeCl3 could improve photosynthesis action by promoting photosynthesis rate, increasing chlorophyll and carotenoid content, and stimulating the activity of Hill reaction. Consequently, all the indexes with Ce＋UV-B treatment were better than those with UV-B treatment. Through the analysis on the dynamic curves of photosynthesis rate, chlorophyll content and Hill reaction activity with six treatments during stress and recovery phase, we found that the decreased rate of three indices with Ce＋UV-B treatments during stress phase was lower, whereas the restored rate during recovery phase was higher, and therefore showed better restoring effect, compared to those of UV-B treatments. All these indicated that Ce could alleviate the inhibition of UV-B on photosynthesis in plants to a certain extent. In addition, according to the coefficients of correlation between chlorophyll content, Hill reaction activity and photosynthesis rate, we considered that the change of Hill reaction activity have a relatively obvious influence on photosynthesis action.