Export of reducing power from chloroplasts to cytoplasm serves to balance the NADPH/ATP ratio that is optimal for CO₂ assimilation. Rapid cytoplasmic streaming in characean algae conveys the exported metabolites downstream towards the shaded plastids where envelope transporters may operate for the import of reducing power in accordance with the direction of concentration gradients. Import of reducing equivalents by chloroplasts in the analyzed area transiently enhances the pulse-modulated chlorophyll fluorescence F′ controlled by the redox state of photosystem II acceptor Q_A. When the microfluidic pathway was transferred to darkness while the analyzed cell area remained in dim background light, the amplitude of cyclosis-mediated F′ changes dropped sharply and then recovered within 5–10 min. The suppression of long-distance signaling indicates temporal depletion of transmitted metabolites in the streaming cytoplasm. The return to overall background illumination induced an exceptionally large F′ response to the first local light pulse admitted to a remote cell region. This indicates the appearance of excess reductants in the streaming cytoplasm at a certain stage of photosynthetic induction. The results suggest highly dynamic exchange of metabolites between stationary chloroplasts lining the microfluidic pathway and the streaming cytoplasm upon light–dark and dark–light transitions. Evidence is obtained that slow stages of chlorophyll fluorescence induction in algae with rapid cytoplasmic streaming directly depend on cyclosis-mediated long-distance delivery of metabolites produced far beyond the analyzed cell area.

从叶绿体向细胞质输出还原力可平衡NADPH / ATP比率，该比率最适合CO ₂同化。查拉藻藻类中的快速细胞质流将出口的代谢产物向着阴影的质体输送到下游，在该处质膜转运蛋白可以根据浓度梯度的方向进行进口，以降低功率。在分析区域中，通过叶绿体导入还原当量会瞬时增强受光系统II受体Q _A的氧化还原状态控制的脉冲调制叶绿素荧光F'。当微流途径转移到黑暗中，而被分析的细胞区域仍保持在昏暗的背景光下时，环化作用介导的F'的振幅变化急剧下降，然后在5-10分钟内恢复。远距离信号转导的抑制表明流动细胞质中传输代谢物的时间消耗。回到整体背景照明会导致异常大的F'对进入远端细胞区域的第一个局部光脉冲的响应。这表明在光合作用的某个阶段，流态细胞质中会出现过量的还原剂。结果表明，在明-暗和暗-光过渡时，位于微流体途径和流动细胞质之间的固定叶绿体之间的代谢物之间的动态交换很高。获得的证据表明，藻类中叶绿素荧光诱导的缓慢阶段以及快速的细胞质流直接取决于环化作用介导的代谢产物的远距离传递，这些代谢产物远远超出了所分析的细胞区域。