1. Tropisms are directional movements or growth response of a plant to the stimulus. In nastic movements, the response of the plant is non-directional. An example of tropism is thigmotropism, which is a growth response to the touch stimulus.
2. Nyctinasty is the nastic movement of plant parts such as leaves and petals in response to darkness.
3. Thigmonasty is a form of nastic movement (of a plant or a fungus) as a response to touch or vibration.
