Companion cells are closely associated with

Options

A. Trichomes
B. Guard cells
C. Sieve tube elements
D. Vessel elements

Answer

**Step-by-Step Solution:**

1. **Understanding Companion Cells**: Companion cells are specialized cells found in the phloem of flowering plants. They play a crucial role in the transport of nutrients and are closely associated with sieve tube elements.

2. **Identifying Phloem Components**: In angiospermic plants, the phloem consists of several components, including sieve tubes, companion cells, phloem parenchyma, and phloem fibers. Among these, sieve tubes and companion cells are primarily responsible for the conduction of food.

3. **Relationship Between Companion Cells and Sieve Tubes**: Companion cells are derived from the same meristematic cell as sieve tube elements during cell division. This close association is important because as sieve tubes mature, they lose their nucleus (become enucleated). The companion cells, which retain their nucleus, help regulate the function of the sieve tubes.

4. **Analyzing the Options**:
- **Trichomes**: These are hair-like structures on the plant surface and are not related to companion cells.
- **Guard Cells**: These cells regulate the opening and closing of stomata but are not associated with companion cells.
- **Sieve Tubes**: Correct answer. Companion cells are closely associated with sieve tube elements.
- **Vessel Elements**: These are part of the xylem and are not related to companion cells.

5. **Conclusion**: Based on the analysis, the correct answer to the question is that companion cells are closely associated with **sieve tubes**.

**Final Answer**: Companion cells are closely associated with **sieve tubes**.

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