HOW PLANTS GAUGE THE TIME OF DAY

Light-sensitive proteins — called photoreceptors — measures time in plants and keeps them abreast of seasons, which is crucial for their development

Plants, much like human beings, have a 24-hour internal ‘body-clock’ or the circadian rhythm that helps them to measure time — the duration of night and day.

The circadian rhythm in plants relies on photoreceptors (light-sensitive proteins) — to measure time and keeps a track of seasons, crucial for their development.

These photoreceptors act as biochemical light switches to help plants gauge the exact time of dusk. In the dark, the proteins kill those that were active during daylight.

But the mechanism that turns off the photoreceptors working in the dark and restores the protein after sunrise, was not known yet.

Researchers from the Yale University found that the work is done by an enzyme, found in the photoreceptors active during the dark.

It stabilises the proteins and helps the plants to control the stability of important circadian clock proteins in the light and dark. It also provides plants with exact information about the timing of dusk.

By carefully tracking dusk, this mechanism helps the plant determine the length of the day and thus communicates the season.

This protein stabiling enzyme is conserved in animal species. It also communicates environmental information that regulates circadian rhythms in animals, a rare conservation of function.

The information may help engineer plants attuned to the environment and to make them better able to respond to changes in climate.