Why do sunflowers follow the sun? More sunlight equals better growth, and the plants know it.
New research shows this sun-tracking is a circadian rhythm. The plants turn overnight to face east because their internal clocks anticipate sunrise.
Biologists at the University of California, Davis demonstrated this regulation and its reliance on the sun when they moved the plants into a room with constant overhead light. Their east-west rhythm deteriorated in a few days.
And when researchers staked plants in place or turned their pots away from the sun in the mornings, they didn't grow as big as the rest.
This sun-following behavior eventually stops naturally when the sunflower matures and its priority shifts from growth to pollination.
Mature sunflowers face east constantly to catch the first rays of the sun. According to the researchers, "bees like warm flowers" — as much as five times more than cold ones.
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