what is the reason for folding of leaves of touch me not plant where they are touched? also mention is it thigmonasty or thigmotropism
Answers
Answer:
The touch-me-not plant's leaves droop when touched, as the water present in the leaves flows back into the plant in response to the stimulus. EXPLANATION: The touch-me-not plant (Mimosa pudica) is an interesting plant as it is one of the plants which can actively respond to a physical or environmental stimulus
Explanation:
Mimosa pudica is a perennial herb of the Fabaceae pea family and is native to Central and South America. Also known as the touch-me-not plant or the sensitive plant (also the ‘tickleMe plant’), it is well-known for closing its leaves or folding its leaves inwards when touched.
Mimosa pudica doesn’t only respond seismonastic movements; it also closes upon being heated. When the plant is exposed to such stimuli, it begins to undergo a series of biochemical and bioelectrical changes that allow it to bend inwards.
The movement originates at the pulvinus, pad-like swellings of petioles and stems that have the ability to twist, which is what allows them to move. The pulvinus has two types of cells, the extensor cells and the flexor cells, which are located in opposition to one another. When the plant experiences a touch, the extensor cells flex, while the flexor cells stretch, jointly creating the movement.
This bending occurs due to a change in the turgor pressure of the extensor cells. The turgor pressure is the force that the water within the cells exerts on the cell walls, helping the cells maintain their shape.
The stimulus (touch) leads to potassium (K+) ions and chlorine (Cl–) ions exiting the cells, mostly likely through ion pumps— protein channels within the cell membrane that allow the transport of ions through the membrane. The reduced concentration of ions from within the cells and the subsequent increase outside creates a chemical gradient leading to water molecules exiting the cell through osmosis. This process might be quickened by the presence of aquaporins—protein channels that allow water to freely pass through the cell membrane.