Petal Power: The Origin Of A Flower's Flashy Allure

Enlarge (Courtesy of John Ohlrogge)

A scanning electron microscope view of nanoridges on the surface of a flower petal.

(Courtesy of John Ohlrogge)

A scanning electron microscope view of nanoridges on the surface of a flower petal.

Deep sea corals? A Brillo Pad convention? No and no. It's a close-up look at a flower's clever way of getting bees to make a pit stop.

Those rows of wiggly lines are microscopic ridges on the surface of a flower petal. Plant experts have known about them for at least 75 years, but their exact function still remains a mystery.

Some have proposed that the ridges act like Velcro, and help bees get a grip on flowers . Others have suggested that they trap droplets of water that give petals a "come hither" sparkle. Or, because of the way the ridges are arranged, they could create an iridescent shimmer that amounts to a flashing "Open For Business" sign for passing pollinators.

But even if their exact function isn't known, researchers at Michigan State University have at least figured out how plants manufacture the ridges.

According to the study in the Proceedings of the National Academy of Sciences, the tiny structures form on the surface of the plant, not in the underlying layers as some have speculated. Researchers also found that the ridges are made of "cutin polyester," a material in the waxy outer layer of plants that helps protect them from drying out.

And why do we care? For one thing, the discovery could give researchers a model for designing microscopic objects — like nanomachines — with easily gripped, non-skid surfaces.

Jason is a producer with NPR's science desk. Check out his previous blog dispatches from Antarctica.

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