How the Venus Flytrap snaps

How the Venus Flytrap Sanos

Yoël Forterre, Jan M. Skotheim, Jacques Dumais & L. Mahadevan

Nature 433, 421-425 (27 January 2005)

Keywords

elastic deformation, instability

Summary

Although people rarely think about plant movement, there are examples of rapid behavior in the plant kingdom. Some examples include dispersing seeds or pollen and capturing prey. The Venus Fly Trap is one dramatic examples. Previous researcher have searched for a purely biological basis for the rapid motion of the plant, such as "acid-induced wall loosening" or a loss of turgor pressure inside special motor cells. However, much of the behavior can be understood just in terms of elastic deformation. The leaves are curved outwards (convex) in the open state and curved inwards (concave)in the closed state, with an elastic buckling instability during the transition.

[[Image:MahadevanVenusFig1.jpg] | 400px]

Soft Matter Aspects

As Prof. Howard Stone often advocates for fluid mechanics problems, the best way to approach this situation is to identify the relevant parameters can create a dimensionless parameter. In this case,

<math>\alpha = L^4 \kappa^2 / h^2</math>,

where L is the length of the leaf, <math>\kappa</math> is the observed Gaussian curvature of the open lead, and h is the leaf thickness. A larger value of <math>\alpha</math> corresponds to more difficulty in stretching the midplane by changing the curvature of the leaf.

written by: Naveen N. Sinha