A bedtime alarm is there to wake humans up in the morning but for plants it may be a matter of life or death, new research suggests.

Scientists studied the arabidopsis flower – a member of the mustard family – and found that it uses a biological time-keeper to survive the night.

Plants use sunlight to make their own sugars from photosynthesis during the day and store them to provide energy during the night.

We think this metabolic signal is acting rather like setting an alarm clock before bedtime to ensure the plant’s survival

A metabolic signal adjusts their circadian clock in the evening, ensuring enough energy is conserved to survive the dark hours.

Dr Mike Haydon, formerly from the University of York, said: “We think this metabolic signal is acting rather like setting an alarm clock before bedtime to ensure the plant’s survival.

“Plants must co-ordinate photosynthetic metabolism with the daily environment and adapt rhythmic physiology and development to match carbon availability.”

The research, published in the PNAS journal, involves a set of genes known to be regulated by the chemical compound superoxide, a molecule associated with metabolic activity.

Professor Ian Graham, from the University of York, added: “Distinguishing the effects of light and sugars in photosynthetic cells is challenging.

“Our data suggest a new role for superoxide as a rhythmic sugar-related signal which acts in the evening and affects circadian gene expression and growth.”