What distinguishes the movement of a sensitive plant’s leaves in response to touch from the directional movement of a seedling?

The movement of a sensitive plant’s leaves in response to touch is a rapid, reversible process known as thigmonasty. Upon touch, specialized cells in the leaf base lose turgor pressure, leading to leaf folding as a defense mechanism. In contrast, the directional movement of a seedling, such as bending towards light (phototropism), involves prolonged and irreversible growth responses. Seedlings exhibit differential cell elongation, causing curvature over time. While both responses involve growth, the sensitive plant’s leaf movement is a rapid, temporary reaction to touch, whereas seedling movement is a more gradual, growth-based adjustment to environmental stimuli.