The feedback regulation of photosynthesis depends on the cooperation of multiple signals, including sugars. Herein, the effect of shoot girdling was monitored on a daily basis for three days in green- and red-leafed Prunus cerasifera plants (GLP and RLP, respectively). The effect of anthocyanin presence was investigated in terms of photosynthesis, sugar metabolism and photoprotection. Net photosynthesis (A390) and stomatal conductance were reduced on the first day at 12:00 only in the girdled GLP (29 and 33 %, respectively). Moreover, the girdled GLP displayed at 12:00 higher sucrose, glucose and fructose concentrations than control leaves. Conversely, girdled RLP showed the first reduction of A390 at 18:00, with no significant differences at 12:00 in sucrose and glucose concentrations. The increased biosynthesis of anthocyanins that was only detected in girdled RLP contributed to lowering the accumulation of hexoses. Overall, these results revealed a sugar-buffering role exerted by anthocyanins that positively influence the feedback regulation of photosynthesis. Moreover, non-photochemical quenching, namely pNPQ, revealed the ability of anthocyanins to photoprotect photosystem II from supernumerary photons reaching the chloroplast, whose function was compromised by girdling. The present study provides a starting point to understand the possible link between photosynthesis regulation through sugar signalling and anthocyanin upregulation.

中文翻译：

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红叶樱桃花青素诱导的花青素积累：对光合作用、光保护和糖代谢的影响

光合作用的反馈调节依赖于包括糖在内的多种信号的协同作用。在此，在绿叶和红叶樱桃属植物（分别为 GLP 和 RLP）中连续三天每天监测枝条环剥的效果。在光合作用、糖代谢和光保护方面研究了花青素存在的影响。仅在带环 GLP 的第一天 12:00，净光合作用 (A390) 和气孔导度降低（分别为 29% 和 33%）。此外，带环的 GLP 在 12:00 显示出比对照叶更高的蔗糖、葡萄糖和果糖浓度。相反，束带 RLP 在 18:00 显示 A390 的第一次减少，在 12:00 蔗糖和葡萄糖浓度没有显着差异。仅在环化 RLP 中检测到的花青素生物合成增加有助于降低己糖的积累。总体而言，这些结果揭示了花青素发挥的糖缓冲作用，对光合作用的反馈调节产生积极影响。此外，非光化学淬灭，即 pNPQ，揭示了花青素光保护光系统 II 免受到达叶绿体的多余光子的能力，叶绿体的功能受到环切的影响。本研究为了解通过糖信号传导的光合作用调节与花青素上调之间可能存在的联系提供了一个起点。这些结果揭示了花青素发挥的糖缓冲作用，对光合作用的反馈调节产生积极影响。此外，非光化学淬灭，即 pNPQ，揭示了花青素光保护光系统 II 免受到达叶绿体的多余光子的能力，叶绿体的功能受到环切的影响。本研究为了解通过糖信号传导的光合作用调节与花青素上调之间可能存在的联系提供了一个起点。这些结果揭示了花青素发挥的糖缓冲作用，对光合作用的反馈调节产生积极影响。此外，非光化学淬灭，即 pNPQ，揭示了花青素光保护光系统 II 免受到达叶绿体的多余光子的能力，叶绿体的功能受到环切的影响。本研究为了解通过糖信号传导的光合作用调节与花青素上调之间可能存在的联系提供了一个起点。