Endodermis is impervious to water because of a band of suberised matrix called.

Answer

**Step-by-Step Solution:**

1. **Understanding the Endodermis**: The endodermis is a specialized layer of cells in the roots of plants that plays a crucial role in regulating the movement of water and nutrients from the soil into the vascular system of the plant.

2. **Function of the Endodermis**: One of the key functions of the endodermis is to act as a barrier to the passive flow of water and solutes. This is important for maintaining the plant's internal environment and ensuring that only certain substances can enter the vascular system.

3. **Role of the Casparian Strip**: The endodermis is impervious to water due to the presence of a specific structure known as the Casparian strip. This strip is a band of suberized (wax-like) material that is deposited in the cell walls of the endodermis.

4. **Composition of the Casparian Strip**: The Casparian strip is chemically different from the rest of the cell wall. While the primary cell wall is typically made of cellulose and may contain lignin, the Casparian strip is primarily composed of suberin, which makes it hydrophobic (water-repelling).

5. **Location and Structure**: The Casparian strip is located on the radial and tangential walls of the endodermal cells. It is usually narrower than the cell wall itself and is positioned closer to the inner tangential wall of the endodermis.

6. **Conclusion**: The presence of the Casparian strip is what makes the endodermis impervious to water, thereby regulating the flow of water and solutes into the plant's vascular system.

**Final Answer**: The band of suberized matrix in the endodermis that makes it impervious to water is called the **Casparian strip**.

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