Y. Forterre, P. Marmottant, C. Quilliet, X. Noblin "Physics of rapid movements in plants" Europhysics News, 47/1 (2016)

http://www.europhysicsnews.org/articles/epn/abs/2016/01/epn2016471p27/epn2016471p27.html

Plants move, and not only under the action of the wind or during growth. Although they lack muscle, some have developed mechanisms to generate surprisingly fast movements, with speeds (about 10 m/s) and accelerations (thousands of g) that compete and even surpass those encountered in the animal kingdom. These fast movements are used to fulfill important functions such as reproduction (pollen catapult in some Orchids, explosive dispersal of seeds), defense against predators (the folding of the Mimosa pudica leaves) or nutrition (the traps of carniv- orous plants). They have fascinated scientists since the first observations by Darwin and Linné and raise important questions in biology related to water transport across the cellular membrane, the mechanics of the cell wall or the perception of mechanical signals by plants. In this article, we discuss the physical mechanisms developed by plants to generate these rapid movements, in the light of recent studies carried at the frontiers of physics and biology.