Question

Difference between tactic,tropic,and nastic movements in plants

Answer 1

The stimuli for the nastic movements may be unidirectional or diffused. The tropic movements are related to the direction of stimuli. Nastic movements are NOT related to the direction of stimuli. Tropic movements are caused by the cell divisions in the organ.

Answer 2

Tactic movements are types of locomotion movements that are caused by certain unidirectional stimuli from outside.

The direction is usually controlled by the stimulus direction.

Nastic movements are different than the tropic movements because tropic responses depend on the stimulus direction, whereas nastic movement direction is independent of the position of stimulus.

A tropic movement is generally a growth movement but a nastic movement may or may not be related to a growing movement.