背景回顾：Plants are subjected to fluctuations in light intensity, and this causes unbalanced photosynthetic electron fluxes and overproduction of reactive oxygen species (ROS). Electrons needed for ROS detoxification are drawn, at least partially, from the cellular glutathione (GSH) pool via the ascorbate-glutathione cycle. 

主要研究：Here, we explore the dynamics of the chloroplastic glutathione redox potential (chl-EGSH) using high-temporal-resolution monitoring of Arabidopsis (Arabidopsis thaliana) lines expressing the reduction-oxidation sensitive green fluorescent protein 2 (roGFP2) in chloroplasts. 

试验方法：This was carried out over several days, under dynamic environmental conditions and in correlation with PSII operating efficiency.

结果1-氧化峰值：Peaks in chl-EGSH oxidation during dark-to-light and light-to-dark transitions were observed. 

结果2-二元氧化响应：Increasing light intensities triggered a binary oxidation response, with a threshold around the light saturating point, suggesting two regulated oxidative states of the chl-EGSH. 

结果3-npq1突变体：These patterns were not affected in npq1 plants, which are impaired in nonphotochemical quenching. 

结果4-pgr5突变体：Oscillations between the two oxidation states were observed under fluctuating light in WT and npq1 plants, but not in pgr5 plants, suggesting a role for PSI photoinhibition in regulating the chl-EGSH dynamics. Remarkably, pgr5 plants showed an increase in chl-EGSH oxidation during the nights following light stresses, linking daytime photoinhibition and nighttime GSH metabolism. 

结论：This work provides a systematic view of the dynamics of the in vivo chloroplastic glutathione redox state during varying light conditions.

 摘 要 

植物受到光强波动的影响，导致不平衡的光合电子流和活性氧物质ROS的过量产生。ROS解毒所需的电子部分通过抗坏血酸-谷胱甘肽循环从细胞的谷胱甘肽（GSH）池中提取。本文中，作者通过对在叶绿体中表达氧化还原敏感绿色荧光蛋白roGFP2的拟南芥株系进行高时间分辨率监测，探索了叶绿体谷胱甘肽氧化还原潜力（chl-EGSH）。该实验在动态环境条件下进行数天，与PSII运行效率相关。作者发现chl-EGSH的氧化峰值出现在黑暗—光照和光照—黑暗的转变期。光强的增强会诱导二次氧化响应，在光饱和点附近存在一个阈值，表明chl-EGSH有两种受调控的氧化状态。这些模式在npq1植物中不受影响，而pq1突变体存在非光化学猝灭受损。在波动光照下，野生型和npq1突变体植物中观察到了两种氧化状态之间的周期振荡，而在pgr5突变体植物中没有观察到该现象，表明PSI光抑制在调节chl-EGSH动态中发挥作用。值得注意的是，pgr5突变体植物在光胁迫后的夜间表现出chl-EGSH氧化的增加，这将植物白天受到的光抑制与夜间的GSH代谢关联在一起。本文的研究揭示了植物体内叶绿体谷胱甘肽氧化还原状态在不同光照条件下的动态波动。