Plants don't need a wristwatch, new research suggests they use sugar to tell what time of day it is.
All living creatures including plants, animals, and humans, have an internal "body clock" called the circadian rhythm. The clock gives plants the ability to sense what time is regardless of sunlight exposure, a Biotechnology Sciences Research Council news release reported.
An example of plants adjusting their bodies to the time is the fact that they don't simply react to the sunrise, they prepare themselves for it before the fact.
"This ability to keep time provides an important competitive advantage and is vital in biological processes such as flowering, fragrance emission and leaf movement," the news release reported.
Researchers are working to understand how this system works in plants, and they think sugar may be the key.
When plants convert sunlight into energy through photosynthesis they produce sugar.
The research team observed seedlings growing in "CO2-free air," which would interfere with the photosynthesis. They also looked at genetically modified plants.
The research suggested these sugars could be essential to the function of circadian rhythms. The team noticed they regulated the genes responsible for keeping time.
"Our research shows that sugar levels within a plant play a vital role in synchronizing circadian rhythms with its surrounding environment. Inhibiting photosynthesis, for example, slowed the plants internal clock by between [two] and [three] hours," Doctor Alex Webb, lead researcher at the University of Cambridge, said.
The team concluded photosynthesis has a direct effect on Arabidopsis plants' ability to keep a 24 hour clock through innate circadian rhythms.
"The accumulation of sugar within the plant provides a kind of feedback for the circadian cycle in plants - a bit like resetting a stopwatch. We think this might be a way of telling the plant that energy in the form of sugars is available to perform important metabolic tasks. This mirrors research that has previously shown that feeding times can influence the phase of peripheral clocks in animals," Doctor Mike Haydon, of the University of York, who participated in the study, said.
Another recent study also found circadian rhythms cue plants to release an insect-repelling chemical a few hours before sunrise, right when the bugs are looking for breakfast, a Rice University news release reported.
This chemical has actually been found to possess cancer-fighting compounds, and could benefit health if a person were to eat them at the right time of day.
