What is a tropic movement ?

Tropic Movement: It is directional paratonie growth movement of curvature in which direction of movement is determined by the direction of the

stimulus. They mostly occur in cylindrical organs. Growth response occurs due to differences in the distribution of auxin.

Example. On unidirectional exposure to light, shoots bend towards the source of light (positive phototropism) while roots may bend away from the

source of light (negative phototropism).