March 22, 2011

Researchers Examine Blooming Lilies

Biologists from Harvard University recently examined why the flowers of lilies have characteristically crinkled edges.

PhD student Haiyi Liang and Professor L. Mahadevan carried out the research.

The lily was marked with dots along the edge of the petal as well as the center of the flower. Time-lapse video reveals that the petals grow longer at the edges than in the middle. These dots enabled the researchers to measure every physical change of the flower as it grew from bud to bloom.

"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 lily, (Lilium casablanca), in a water-filled vase, was filmed for four and a half days until the flower was fully open, revealing that the petals' edges grew up to 40% more than their midribs.

Differences in the rate of growth created stress that eventually opened the bud, resulting in lily petals with their tell-tale wrinkles.

Writing in the Proceedings of the National Academy of Sciences the researcher said that, "in addition to infusing a scientific aesthetic into a thing of beauty," the study could be helpful in 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."


Image Caption: The asiatic lily's graceful geometry invites observational and quantitative study. Credit: Photo courtesy of Flickr user KingsbraeGarden/CreativeCommons


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