Thigmonasty

Thigmonasty or seismonasty is the nastic response of a plant or fungus to touch or vibration. Thigmonasty is especially prevalent in the mimosa genus.

Thigmonasty differs from thigmotropism in that it is independent of the direction of the stimulus. For example, tendrils from a climbing plant are thigmotropic because they twine around any support they touch. However, the shutting of a venus fly trap is thigmonastic. The time scale of thigmonastic responses tends to be faster than thigmotropism because thigmonasty depends on turgor and bistable mechanisms rather than growth or cell division. Certain dramatic examples of rapid plant movement such as the sudden drooping of Mimosa pudica are fast enough to observe without time lapse photography.