Function of companion cells is

Options

A. Conduction
B. Maintaining pressure gradient in sieve tube element
C. Mechanical support
D. No specific function

Answer

### Step-by-Step Solution:

1. **Understanding the Context**: The question asks about the function of companion cells, which are part of the phloem tissue in plants. Phloem is responsible for the transport of nutrients, particularly sugars produced in the leaves.

2. **Identifying Components of Phloem**: Phloem consists of two main types of cells: sieve tube elements and companion cells. Sieve tube elements are the primary conducting cells, while companion cells assist them.

3. **Function of Sieve Tube Elements**: Sieve tube elements are responsible for the conduction of food (sugars) throughout the plant. They are elongated cells that facilitate the translocation process.

4. **Role of Companion Cells**: Companion cells are living, nucleated cells that do not conduct food directly. Instead, they play a supportive role for sieve tube elements.

5. **Key Function of Companion Cells**: The primary function of companion cells is to maintain the pressure gradient in the sieve tube elements. This pressure gradient is essential for the loading and unloading of sugars into and out of the sieve tubes.

6. **Conclusion**: The correct answer to the question regarding the function of companion cells is that they maintain the pressure gradient in the sieve tube elements, which aids in the translocation of food.

### Final Answer:
The function of companion cells is to maintain the pressure gradient in the sieve tube elements.

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