Long‐term fluctuating light (FL) conditions are very common in natural environments. The physiological and biochemical mechanisms for acclimation to FL differ between species. However, most of the current conclusions regarding acclimation to FL were made based on studies in algae or Arabidopsis thaliana. It is still unclear how rice (Oryza sativa L.) integrate multiple physiological changes to acclimate to long‐term FL. In this study, we found that rice growth was repressed under long‐term FL. By systematically measuring phenotypes and physiological parameters, we revealed that: (a) under short‐term FL, photosystem I (PSI) was inhibited, while after 1–7 days of long‐term FL, both PSI and PSII were inhibited. Higher acceptor‐side limitation in electron transport and higher overall nonphotochemical quenching (NPQ) explained the lower efficiencies of PSI and PSII, respectively. (b) An increase in pH differences across the thylakoid membrane and a decrease in thylakoid proton conductivity revealed a reduction of ATP synthase activity. (c) Using electron microscopy, we showed a decrease in membrane stacking and stomatal opening after 7 days of FL treatment. Taken together, our results show that electron flow, ATP synthase activity and NPQ regulation are the major processes determining the growth performance of rice under long‐term FL conditions.

中文翻译：

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水稻对长期波动光的适应机制的叶片光合和解剖学见解

在自然环境中，长期波动的光（FL）条件非常普遍。物种之间适应FL的生理和生化机制不同。然而，目前有关FL适应的大多数结论是基于藻类或拟南芥的研究得出的。尚不清楚水稻如何（水稻L.）整合多种生理变化以适应长期FL。在这项研究中，我们发现在长期FL下水稻生长受到抑制。通过系统地测量表型和生理参数，我们发现：（a）在短期FL下，光系统I（PSI）被抑制，而在长期FL 1至7天后，PSI和PSII均被抑制。电子传输中较高的受体侧限制和较高的整体非光化学猝灭（NPQ）分别解释了PSI和PSII的效率较低。（b）整个类囊体膜pH差异的增加和类囊体质子传导性的降低表明ATP合酶活性降低。（c）使用电子显微镜，我们发现FL治疗7天后膜堆积和气孔开口减少。在一起