@Rocket Soul ,
If you put the circadian cycle of plants into Google, you should get a lot of articles.
I am Spanish, so if I put it in Spanish I get many articles, I wouldn't know how to tell you in English.
But I leave you some links to those articles in which I learn about these studies.
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--> The circadian clock is responsible for generating the oscillations of biological processes in coordination with the day and night cycle and the associated changes in light and temperature. The cell cycle, for its part, is responsible for the division and growth of cells. If the cell cycle does not function correctly, the effects on organisms are dramatic: the best known case is the development of cancer. Therefore, the cell cycle must be highly regulated to avoid possible malfunctions.
Scientists have shown for the first time in plants that the circadian clock controls the speed of the cell cycle
Now, a research team from the Agrigenomics Research Center (CRAG), led by CSIC researcher Paloma Mas, has demonstrated for the first time in plants that the circadian clock controls the speed of the cell cycle, and that in this way it regulates the cell growth and division in synchronization with the day and night cycles. “We have shown something that we have suspected for a long time”
---> Dr. Paloma Mas is head of the Molecular Mechanisms of Circadian Clock Function research group at the Agrigenomics Research Center (CRAG). She herself presents her work in this way:
The rotation around the Earth's axis causes the alternation of lights and shadows on our planet. This involves changes in environmental conditions of light and temperature, which have greatly influenced life on Earth. Our cells already have their own clock, capable of measuring the passage of time and telling us what we should do: the biological or circadian clock, which generates rhythms in a 24-hour period. This clock is present in all types of living organisms, even bacteria. The basic mechanism that generates this ability has been preserved.
Plants have to withstand any environmental condition, no matter how adverse it may be, since they cannot move and look for a more appropriate place to live. Throughout history, plants have developed mechanisms that allow them to anticipate and respond to environmental changes.
Thus, plants, in a dark environment, continue to open and close at a certain rate over a 24-hour period.
We have an autonomous clock, but this does not mean that it works isolated from the environmental conditions that surround us. The clock is resynchronized every day. Hence the effects of Jet Lag. The watch follows the rhythm of the place of departure, but adapts/synchronizes with the environmental conditions of our point of arrival. The central oscillator generates positive and negative rhythms that are regulated and generate a rhythmicity that they transmit to the components of the output pathway.
In the case of plants, the clock is important in all stages of their life cycle: if we alter the functioning of their circadian clock we can alter their growth, delay germination, flowering, etc...
At the cellular level, the clock modulates these responses through the stomata, on the surface of the leaves, which control opening and closing. If this does not work well, the plant does not respond well to, for example, drought.