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Time-lapse footage reveals how lily flowers bloom
By Victoria Gill
Science and nature reporter, BBC News


Time-lapse reveals lily blooming

Time-lapse footage has revealed remarkable detail about how a lily blooms.

Writing in the Proceedings of the National Academy of Sciences, researchers said that the discovery shows why the flowers' petals have characteristically crinkled edges.

The footage's careful measurements reveal that the lily petals grow longer at the edges than in the middle.

This puts stress on the bud, eventually bursting it open.

PhD student Haiyi Liang and Professor L Mahadevan from Harvard University, Boston, Massachusetts, US carried out the research.

The scientists marked a lily bud with dots along each petal's edge and "midrib" or central vein.

These dots were markers that enabled them to measure every change in the size and shape of the flower as it went from bud to bloom.

Lily bud opening (Image: PNAS)
I study nature because I am curious, like all of us
Professor L Mahadevan
Harvard University

"I noticed that petals of some flowers are wrinkled and thought that perhaps [these wrinkles were] functional and may play a role in opening," Professor Mahadevan told BBC News. "So I decided to look at it more carefully."

The scientists placed a lily (Lilium casablanca) with its stem immersed in water and filmed it for four and a half days until the flower was fully open.

The experiment revealed that the petals' edges elongated up to 40% more than their midribs.

This difference in the rate and amount of growth created stress that eventually burst open the bud, and resulted in petals with their familiar wrinkles.

The scientists wrote in their paper that, "in addition to infusing a scientific aesthetic into a thing of beauty," their study could aid the design of tiny motors or switches.

"Someone might be inspired to use this natural design, where the edges drive the interior, to build an actuator - a film that changes shape," explained Professor Mahadevan.

"That might be useful as a means to store information or to flip a switch.

"[But] that's not what drove me at all to work on the problem.

"I study nature because I am curious, like all of us. But if we can learn some general principle that someone else might put to use, that is fantastic."

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