The casparian strips of root endodermis is made up of

Options

A. Suberin
B. Cellulose
C. Chitin
D. Keratin

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure**: The Casparian strip is a band of cell wall material found in the endodermis of plant roots. It plays a crucial role in regulating the flow of water and nutrients.

2. **Composition of Casparian Strips**: The primary component of the Casparian strip is a waxy substance known as Suberin. This substance is hydrophobic, meaning it repels water.

3. **Function of Suberin**: The presence of Suberin in the Casparian strip prevents the passive flow of water and solutes through the apoplast (the space outside the cell membranes). Instead, it forces water and nutrients to pass through the symplast (the cytoplasm of the cells).

4. **Transport Mechanism**: Due to the Casparian strip, water and nutrients must enter the endodermal cells, allowing for selective uptake and regulation of substances before they reach the vascular tissue.

5. **Conclusion**: Therefore, the Casparian strips of the root endodermis are made up of Suberin.

**Final Answer**: The Casparian strips of root endodermis are made up of Suberin.

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