A reversible change in the position of plant parts due to a change in turgor pressure in certain specialized cells. The growth observed is independent, and has immediate response to the stimuli. Plants use electrical-chemical means to convey information from cell to cell. For movement to happen, cells change their shape by changing the amount of water in them, resulting in swelling or shrinking of the cell.

Turgor pressure is the force within the cell that pushes the plasma membrane against the cell wall. It occurs due to changes in the osmotic pressure of the cells involved in the movements. Turgor pressure within cells is regulated by osmosis and this also causes the cell wall to expand during growth. Osmosis is the process in which water flows from an area with a low solute concentration, to an adjacent area with a higher solute concentration until equilibrium between the two areas is reached, this helps in maintaining turgor pressure occurring through osmosis, help in maintaining equilibrium in plants to prevent turgor movement. The plants that lack turgor pressure show turgor movement.

Examples of turgor movement in plants are:

● Leaves of Mimosa plant folds and droops down when anyone touch them.

● Leaves of Medicago marina plants close or sleep at night whereas opens up during day time.

Explanation: It can be explained with the example of a complete process. It has been concluded that loss of turgor pressure within the leaves of Mimosa pudica is responsible for the reaction the plant has when touched. In that plant turgor pressure is different in the upper and lower pulvinar cells of the plant, and the movement of potassium and calcium ions throughout the cells cause the increase in turgor pressure. When touched, the pulvinus is activated and exudes contractile proteins, which in turn increases turgor pressure and closes the leaves of the plant.