Study Looks Into Mechanism of Venus Flytrap's Botanical Bite

A native wildflower to the Carolinas, the Venus flytrap, is a unique plant that has astonished botanists the world over by their remarkable ability to trap prey.

This plant has convex bi-lobed leaves with three trigger hairs present on each lobe. When something comes in contact with the hair twice, there are electrical signals that turn the leaves into concave shapes. Once a prey is trapped, the captured insect struggles in order to escape and tickles the trigger hairs. 

This rapid display of botanical movement has fascinated scientists and they have tried to understand the mechanism of the Venus flytrap.

It is assumed that understanding the mechanism of the Venus fly trap's leaf snapping may one day help improve products such as release-on-command coatings and adhesives, electronic circuits, optical lenses and drug delivery.

A study is being conducted by a team of French physicists from the National Center for Scientific Research and Aix-Marseille University in Marseille, France. The team is working to understand this movement and get more insight into this unique mechanism.

This work extends the findings of Dr. Yoel Forterre and researchers from Harvard University who discovered several years ago that the curvature of the Venus fly-trap's leaf changes while closing due to a snap-buckling instability in the leaf structure related to the shell-like geometry of the leaves. 

Mathieu Colombani, Ph.D. student in Forterre's laboratory is now conducting experiments to reveal the physical mechanisms behind this movement. He says, "The extremely high pressure inside the Venus fly trap cells prompted us to suspect that changes with a cell's pressure regime could be a key component driving this rapid leaf movement."

With the help of the microfluidic pressure the Colombani team will try to measure individual cells. This task is  a bit challenging as it requires the living plant to be immobilized with dental silicone paste while the probe is inserted using a micromanipulator guided by binoculars. They take pressure measurements before and after leaf closure. By injecting or removing a known amount of liquid and recording the cellular responses they will measure cell wall elasticity as well as take other measurements.

"By measuring osmotic pressure and elasticity of leaf cells we hope to come closer to explaining the snapping mechanism,'' Colombani explains.

hey will present their findings at the 65th meeting of the American Physical Society's (APS) Division of Fluid Dynamics (DFD), Nov. 18 -- 20, 2012, in San Diego, Calif.