What is the role of transfer cells in sugar translocation?

Options

A. They serve to load photosynthate into sieve tubes
B. They increase DPD of sieve tubes
C. They synthesise P-proteins
D. They synthesise callose

Answer

**Step-by-Step Solution:**

1. **Understanding Transfer Cells:**
Transfer cells are specialized cells found in the phloem of plants. They play a crucial role in the process of sugar translocation, which is the movement of sugars produced during photosynthesis from the leaves to other parts of the plant.

2. **Function of Transfer Cells:**
The primary function of transfer cells is to facilitate the loading of sugars (mainly sucrose) into the sieve tubes of the phloem. This is essential for the efficient transport of sugars throughout the plant.

3. **Mechanism of Sugar Loading:**
Transfer cells have an increased surface area due to their wall ingrowths, which enhances their ability to uptake sugars from the surrounding tissues. They transport these sugars from the apoplast (the space outside the cell membranes) into the symplast (the cytoplasm of the sieve tube elements).

4. **Importance of Sugar Loading:**
By loading sugars into the sieve tubes, transfer cells ensure that the sugars can be transported to areas of the plant that require energy for growth, storage, or metabolism.

5. **Conclusion:**
Therefore, the correct answer to the question about the role of transfer cells in sugar translocation is that they serve to load photosynthetic products into sieve tubes.

**Final Answer:**
Transfer cells serve to load photosynthetic products into sieve tubes.

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