Water moving through the apoplast from the soil to stele cells must crosses a plasma membrane in the cells of

Options

A. Root hairs
B. Cortex
C. Endodermis
D. Vessel

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which cells the water must cross the plasma membrane while moving through the apoplast pathway from the soil to the stele cells. The stele includes all tissues inside the endodermis.

2. **Identifying the Pathway**: Water moves from the soil into the root and travels through the apoplast pathway, which involves movement through the cell walls and intercellular spaces.

3. **Identifying the Cells**: The cells that water must pass through include:
- **Root Hairs**: The first point of contact with water from the soil.
- **Cortex**: The layer of cells beneath the epidermis.
- **Endodermis**: The innermost layer of the cortex, which has a casparian strip.

4. **Understanding the Casparian Strip**: The casparian strip is a band of cell wall material that is impregnated with suberin, making it water-impermeable. This strip forces water to cross the plasma membrane of the endodermal cells to enter the stele.

5. **Conclusion**: Since the question specifically asks where the water must cross a plasma membrane, the answer is that water must cross the plasma membrane in the **endodermis** due to the presence of the casparian strip.

6. **Final Answer**: The correct option is **endodermis**.

---