The companion cells are specialised parenchymatous cells, which are closely associated with :-

Options

A. Sieve tube elements
B. Xylem
C. Phloem
D. Subsidiary cells

Answer

**Step-by-Step Solution:**

1. **Understanding Companion Cells**: Companion cells are specialized parenchymatous cells found in the phloem tissue of plants. They play a crucial role in the transport of nutrients.

2. **Identifying the Association**: Companion cells are closely associated with sieve tube elements. Sieve tube elements are the main conduits for transporting sugars and other metabolic products in the phloem.

3. **Development of Companion Cells and Sieve Tube Elements**: Both companion cells and sieve tube elements originate from the same meristematic tissue. During development, a larger daughter cell becomes a sieve element, while smaller daughter cells differentiate into companion cells.

4. **Functionality**: Companion cells support the sieve tube elements by providing them with the necessary metabolic support, as sieve tube elements lack a nucleus and other organelles.

5. **Conclusion**: Therefore, the correct answer to the question is that companion cells are closely associated with sieve tube elements.

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

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