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Multiple Choice
In a 'touch me not' plant (Mimosa pudica), what is the primary response observed when the leaves are touched?
A
The stem changes color.
B
The roots grow faster.
C
The plant releases a strong odor.
D
The leaves fold and droop rapidly.
Verified step by step guidance
1
Understand the unique characteristic of Mimosa pudica, commonly known as the 'touch me not' plant. It exhibits a rapid movement response to physical stimuli, which is a form of thigmonasty (a nastic movement triggered by touch).
Recognize that thigmonasty in Mimosa pudica is caused by changes in turgor pressure within specialized cells at the base of the leaflets and petioles, called pulvini.
When the leaves are touched, an electrical signal (action potential) is generated, which triggers the movement. This signal causes the cells in the pulvini to lose water rapidly, leading to a decrease in turgor pressure.
As a result of the loss of turgor pressure, the leaves fold and droop. This is thought to be a defense mechanism to deter herbivores or protect the plant from environmental stress.
Conclude that the primary response observed when the leaves of Mimosa pudica are touched is the rapid folding and drooping of the leaves, not changes in stem color, root growth, or odor release.