Softening cells walls provide the snap to a Venus flytrap

It’s a mystery that stumped Darwin and many researchers since: what exactly drives the snap shut of a Venus flytrap? Now, Jeongeun Ryu and colleagues have the answer: a rapid, one-second softening of the cell walls on the outer epidermis of the trap. Their careful experiments with the Venus flytrap confirm that the snap action occurs too quickly to be controlled by water transport within the trap, which had been one of the leading mechanical explanations. The study highlights a new mode of plant movement “based on dynamic tuning of material properties,” according to Ryu et al. This new actuation mechanism could offer bio-inspiration for muscle-free movement in soft robotics and smart materials, they suggest. The swift softening of the outer epidermal cell wall in the plant’s trap appears to be the fastest mechanical shift reported for plant cell walls, although the exact molecular mechanism remains unclear. In a related Perspective, Jacques Dumais discusses how the new research may help clarify the evolutionary history behind the intricate trap.