Question:
The closing and opening of the leaves of Mimosa pudica is due to
The closing and opening of the leaves of Mimosa pudica is due to
Updated On: Aug 20, 2024
- seismonastic movement
- chemonastic movement
- thermonastic movement
- hydrotropic movement.
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The Correct Option is A
Solution and Explanation
Nastic movements occur in response to a stimulus. It is independent of its direction. They are shown by bifacial organs (leaves, sepals, petals) and are in response to diffused external stimulus. Fig.: Seismonastic movement Seismonastic movements are due to shock or touch stimulus. Such movements are shown by Mimosa pudica. The leaf of Mimosa is compound having four pinna and each pinna is having many pinnules. If a terminal pinnule is touched, the whole leaf droops down. This is due to fact that at the bases of pinnules, pinna and whole leaf, swollen structure called pulvinus is present and drooping is due to loss of turgidity of lower portion of pulvinus.
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Concepts Used:
Leaf
A primary function of the leaf is to provide nourishment for a plant. Leaves get this by extracting water from the earth and carbon dioxide from the air with the help of sunshine.
Parts of a leaf
Following are the parts of a leaf:
- The top part of the leaf is the apex or tip that can be round, pointed, and smooth.
- On most leaves, the lamina, or leaf blade, is the broadest part of the leaf.
- A petiole is a leaf that links to the plant stem.
- Stipules, which are little green addendums near the base of the petiole, can also be seen on leaves.
- Most leaves have a midrib that branches out to initiate vascular tissue veins on the sides.
- Margin refers to the leaf's outer border, which varies depending on the plant type.
- At the bottom of the blade, the base is found; it can be flat, heart-shaped, and round.