Some scientists have revealed that the biological clocks of plants help them to react to changes linked to sunrise and sunset and day length. These results shed new light on how living things react to the changing rhythms of daylight and may help us better understand the effects of jetlag and shift work.
The results obtained by scientists in Hungary and the United Kingdom were published in the journal Molecular Systems Biology. The EU supported this work through the project EUCLOCK (“Entrainment of the Circadian Clock”), which received 12.3 million under the thematic area “Life sciences, genomics and biotechnology for health in the Sixth Framework Programme (FP6).
Many living things have circadian clocks, which ensure that various aspects of metabolic, physiological and behavioral occur at optimal times during the day. Studies have shown that several genes are more active at certain times of the day and genes linked to them from the functional point of view are often set to be active at the same time. The biological clocks that control these processes are “synchronized” with information such as the light.
The biological clock helps plants to better manage the carbon metabolism.
During the day, plants use energy from the sun to transform carbon dioxide into sugars and oxygen. This occurs in those parts of the plant chloroplasts. Some of the sugars are retained in the chloroplasts in the form of “transient starch.
“These are broken down to give rise to sugar during the night, preventing the inhibition of plant growth caused dall’inedia,” the researchers write. “Several genes involved in starch metabolism are regulated rhythmically,” they add.
In this study, the researchers tested different mathematical models and have conducted several experiments to determine the complexity of the processes that control? ‘Circadian clock of Arabidopsis thaliana. They also wanted to determine how the clock maintains enough flexibility to adapt to seasonal changes and the times of sunrise and sunset.
Their studies have shown that a mathematical model with three feedback loops was better to predict the results of practical experiments than models with only one or two feedback loops.
“We have shown that increased complexity of the model allowed the circadian phase of the components of the model to change flexibly in response to photoperiod of the light-dark cycle,” say the scientists.
According to the researchers, “The behavior of the model can be conceptually divided in the effects of the input light, the effects of hours of the morning on the day of the cycle genes that are expressed in the evening, and the effects of night on the evening of the cycle genes expressing themselves in the morning. ”
The scientists believe their findings could be important for the agricultural sciences. “Corrected time of rhythmic processes, such as the degradation of starch, are essential for growth, so it is very likely that this temporal regulation of vegetative physiology has been subject to natural selection and may contribute to the improvement of crops,” emphasized.
The results could have implications for human medicine, sleepiness, body temperature, blood pressure and physical strength varies according to a 24-hour rhythm.
“Our results give us valuable information on how plants – and people – react to changes in day length,” said Professor Andrew Millar, University of Edinburgh in the UK, who led the study. “They could provide a new method to understand how to adapt when the daily rhythms of light and darkness are broken.”
