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. 2021 Mar 12;186(2):910–928. doi: 10.1093/plphys/kiab123

Figure 9.

Figure 9

Regulation of redox metabolism by light during bud outgrowth process: a CK-dependent pathway. This synthetic scheme highlights the central role of redox metabolism in the bud outgrowth photocontrol process and its regulation by light and CK. In light (L:D 16:8), CK synthesis and transport in buds are promoted (Roman et al., 2016). Moreover, after beheading in light, the H2O2 content in buds decreased, while GSH pool increased (Porcher et al., 2020). Furthermore, CK stimulates GSH synthesis and contributed to the decrease of H2O2 contents, notably through the AsA–GSH scavenging pathways. In contrast, darkness prevents the H2O2 decrease that normally occurs in light and drastically reduces the GSH pool. In summary, the light stimulation of CK synthesis and transport increases the GSH content and activates the AsA–GSH scavenging system to initiate the decrease in H2O2 in bud that will, in turn, restore the cell division and expansion that are required to initiate the outgrowing process (Reichheld et al., 1999; Porcher et al., 2020). Green lines indicate stimulation, red lines inhibitions, and gray lines nonactive pathways.