铈对UV-B胁迫下菠菜离体叶绿体光化学反应影响

Effect of Cerium on Photochemical Reactions in Isolated Intact Chloroplast from Spinach Exposed to Supplementary UV-B Radiation

以菠菜离体完整叶绿体为试材,研究Ce(Ⅲ)对UV-B辐射(4.5W·m-2)胁迫下叶绿体Hill反应活力、光合磷酸化活性以及Mg2+-ATPase活性的影响。结果表明,菠菜离体完整叶绿体Hill反应活力、光合磷酸化活性、Mg2+-ATPase活性在同一时段的变化规律均为:Ce(Ⅲ)>CK>Ce(Ⅲ)+T>T。这表明,UV-B辐射下叶绿体光化学反应活性降低是光合作用受抑的能量基础。Ce(Ⅲ)的介入可在一定程度上减轻UV-B辐射对叶绿体光化学反应活性的抑制,而UV-B辐射(4.5W·m-2)胁迫结束后离体叶绿体自修复与Ce(Ⅲ)调控恢复的效果均不明显,揭示离体叶绿体因失去叶片附属结构保护,对UV-B辐射敏感性增加。

Effects of cerium on Hill reaction activity, photophosphorylation rate and Mg^2＋-ATPase activity in spinach chloroplasts exposed to supplementary UV-B radiation （4.5 W·m^-2） were studied. The response sequences of Hill reaction activity, photophosphorylation rate and the Mg^2＋-ATPase activity under four treatments were all as follows： CK〉T〉Ce（ Ⅲ ）〉Ce（ Ⅲ）＋T, indicating that the UV-B-induced inhibition to photochemical reaction activities caused a decrease in photosynthesis by reducing energy contribution. Ce（Ⅲ ） could alleviate the UV-B-induced inhibition to photochemical reaction activities in isolated intact chloroplast from spinach. When UV-B radiation stopped, the self-repairing in chloroplast was not realized, and the regulating effects of Ce（ Ⅲ ） on restoration in chloroplast were not significant, suggesting that the sensitivity of isolated chloroplast to UV-B radiation was increased because of losing the protection of accessory organs in leaf.