Young sunflowers dance; old ones choose the east

A young sunflower does exactly what its name promises: it follows the sun. It wakes facing east, accompanies it to the west and, at night, retraces its path to await the dawn in position. A slow dance, repeated every day.

In 2016, a team at the University of California discovered how it does it: one side of the stem grows by day and the other by night, taking turns, guided by an internal clock. Turn a sunflower around in its pot and it takes days to «reset its clock».

But on maturing, the dance stops: the adult sunflower settles, fixed, facing east. Why? Scientists measured its temperature: east-facing flowers warm up earlier in the morning, and bees prefer warm flowers. Facing east multiplies the visits of pollinators.

Young, chase the light. Grown, know where it will rise. Not a bad life story.

Source: Science