University researchers tested computer models of gene networks in a simple cress plant to determine the role played by a protein, known as TOC1, in governing these daily cycles.

The model shows how 12 genes work together to run the plant's complex clockwork, and reset the clock at dawn and dusk each day.

Researchers found that the TOC1 protein, which was previously linked to helping plants wake up, is in fact involved in dampening gene activity in the evening.

This helps plants stay dormant at night.

Contradictory finding

"The 24-hour rhythms of biological clocks affect all living things including plants, animals and people, with wide-ranging effects on sleep, metabolism and immunity," said Professor Andrew Millar of the School of Biological Sciences.

The findings contradict what scientists had previously understood about the gene and its role in early morning activity.

Scientists in Barcelona independently reached a similar conclusion to the Edinburgh team.

The two studies pave the way for further research to define how the cycles improve plant growth and allow plants to adapt to our changing environment.

Changing seasons

These internal 24-hour cycles -- known as circadian clocks -- also allow people, animals and plants to make tiny adjustments as daylight changes, and adapt to changing seasons.

Researchers hope their discovery will bring them a step closer to understanding other seasonal rhythms that affect plants and people.

These include the flowering of staple crops such as wheat, barley and rice, and the breeding patterns of animals.

"We are now far better placed to understand how this complex process impacts on the plant's life and what happens when the rhythms are interrupted, for example by climate change," said Millar.

Note: If no author is given, the source is cited instead.

• Endangered Plants
• Nature
• Botany

• Grassland
• Rainforests
• Climate

• Circadian rhythm
• Transgenic plants
• Heirloom plant
• Deciduous
• Herbivore
• Plant cell