Question

Differentiate between tropic and nastic movements in plants.

Answer 1

Growth-dependent movement:

The movement in the plant due to unequal growth in different parts of a plant's organs in response to an environmental stimulus is called growth-dependent movement.

Induced movement of growth:

1. The movement of a plant due to an external stimulus is known as the induced movement of growth.
2. It is of two types; nastic and tropic movements.

Tropic Movement	Nastic Movement
This movement occurs in plants due to the presence of a directional stimulus.	This movement does not require any directional stimulus.
This movement does not occur due to turgor changes.	This movement occurs due to the change in turgor pressure.
This movement involves unidirectional growth.	This movement does not involve any growth.
Some examples of tropic movements are hydrotropism, phototropism, geotropism, etc.	Some examples of nastic movements are thigmonasty, photonasty, nyctinasty, etc.