i wasn't aware that NYT had so many bugs... i've been a member for years and never had a problem (then again i have virus/adware/spyware protection programs up the wazoo)
anyway here's the text:
The Secret Behind the Snap
The closing of a Venus flytrap is far less violent than a volcanic eruption, but in its own way it is just as spectacular. The rapid motion - the two leaves can close on a fly or other prey in about a tenth of a second - is remarkable for a plant.
It's also a bit mysterious. While scientists have long known that the plant starts closing when hairs within the leaf are mechanically stimulated, and while they have speculated on what occurs at the cellular level, the precise mechanism has never been fully explained.
Now, Dr. Lakshminarayanan Mahadevan of Harvard and colleagues have shown the secret behind the snap.
The action, they say, is a function of the changing curvature of the leaves; the plant stores elastic energy and then releases it suddenly. It's something like what happens to a curved tape measure when it is bent back on itself. It doesn't deform slowly, but quickly snaps instead.
The researchers first studied the action by painting tiny fluorescent dots on the outside of flytrap leaves and using high-speed video to record the movement of the dots as the leaves closed. Then they created a mathematical model to describe the action.
Their work is described in Nature.
The researchers still don't have much to say about the cellular activity - presumably the quick movement of water into or out of certain cells - that underlies the closing. But the movement itself, they say, is determined by the leaf geometry.
The leaf is curved in two directions, and bending in one direction causes stretching in the other. At some point the stretching gets to be too much, and the leaf deforms rapidly.