2020-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/697931Organisms on the earth synchronize their physiological processes with external cues caused by the earth rotation to form ~24-hr circadian rhythms. The circadian rhythms are controlled by the inner clock, circadian clock, which is tightly entrained also by the environmental cycling changes. Each of plant cells has the inner clock for controlling their daily rhythms and most cells of plant body have photoreceptors such as phytochromes and cryptochromes for light inputs to entrain the circadian clock. For a long time, the circadian clock in plant is considered as a decentralized clock, since cells are naturally synchronized by the daily changes in the living environment. In recent years, it has been demonstrated that individual clocks of cells in the shoot and root apical meristems form hierarchical coupled oscillators to orchestrate the circadian rhythms in other organs. In addition to the shoot and root apexes, the clocks in the vasculature of the leaf also coupled the clock of the mesophyll cells. These organs involved in clock coupling share a common feature of having pluripotent stem cells embedded. Whether the pluripotent stem cells are in charge of clock coupling has never been addressed. In this proposal, we ask this important biological question by aiming on the role of stem cells in coordination of circadian clocks in plant individual cells. We propose a series of experiments to examine the functions of stem cell in the clock coupling. Our proposed studies will unravel the possible mechanism of meristems involve in circadian clocks orchestrating across the plant body.circadian clock; circadian rhythm; shoot apical meristem (SAM); root apical meristem (RAM); Arabidopsis; stem cell; callus