Biological complexity:circadian controls of plant breathing (Introduction)

by David Turell , Tuesday, March 17, 2020, 21:54 (1498 days ago) @ David Turell

It controls how plants use water and save it:

https://phys.org/news/2020-03-clockwork-transpires.html

"Plants are so dependent on daylight that circadian clocks are even more influential, regulating the rate of photosynthesis, gas exchange, and transpiration, which is the flow of water through the stem and evaporation from leaves.

"Now researchers have discovered that these biological clocks play a critical role in the consumption of water, allowing plants to use this precious resource more efficiently.

"They carried out a series of experiments with model laboratory plants in which the genes encoding circadian rhythms had been changed.

"Some changes made plants use more water in relation to growth but, unexpectedly, the experiments revealed that some of these changes to circadian rhythms allowed plants to grow strong and healthily whilst using less water. The study reveals that it is the whole circadian system that affects water use efficiency not just a specific part.

***

"Plants transpire water with a daily rhythm because the stomata, tiny pores on the surface of leaves, generally open only in the day. Previous studies showed that daily opening is regulated by circadian rhythms.

"'We reasoned that circadian rhythms might have a big impact upon the amount of water that plants use. And our experiments show this to be the case," explains Dr. Antony Dodd of the John Innes Centre, who is the senior author of the study."

Comment: All organisms follow the 24 hour daily pattern. What is not described here is how evolution was able to design pores that open and close on schedule. I'm sure there are specific molecular reactions based on sunlight intensity.