Question

The major component of Casparian strip is:
(A)
(B)
(C)
(D)

• A. Suberin
• B. Waxes
• C. Starch
• D. Sucrose

Hint:

Casparian Strip = Endodermis = Suberin = Control Valve.
It ensures that the plant has full control over the minerals being transported to the shoot.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the primary chemical substance that makes up the Casparian strip, a specialized structure found in the roots of plants.
Detailed Explanation:

• Location of Casparian Strip:
The Casparian strip is a band of waterproof material found in the radial and transverse walls of the Endodermis (the innermost layer of the root cortex).

• Composition:
The strip is primarily composed of Suberin, a complex, hydrophobic waxy polymer. In some species, lignin may also be present.

• Function:
Because suberin is impermeable to water, the Casparian strip blocks the apoplastic movement of water and dissolved minerals through the cell walls.
This forces water and nutrients to enter the cytoplasm of the endodermal cells (the symplastic pathway), allowing the plant to selectively filter what enters the vascular cylinder (stele).

Step 2: Final Answer:
Suberin is the major waxy component that makes the Casparian strip waterproof.