Why Do Some Plants Close Their Leaves When You Touch Them?

A plant folding its leaves when you touch it can feel almost magical. One moment the foliage is open and relaxed, and seconds later it appears to shrink away from your finger. The best-known example is Mimosa pudica , commonly called the sensitive plant or touch-me-not. Unlike animals, plants do not have muscles or a nervous system, yet this remarkable species can respond rapidly to physical stimulation. Scientists have discovered that the movement involves electrical signalling, specialised structures and changes in water pressure inside cells.