The hormones which regulate phloem transport are

Options

A. auxins
B. cytokinins
C. gibberellins
D. ethylene

Answer

**Step-by-Step Solution:**

1. **Identify the Hormones Involved in Phloem Transport:**
- The question asks for hormones that regulate phloem transport.

2. **Focus on Cytokinins:**
- One of the key hormones involved in regulating phloem transport is **cytokinin**.

3. **Understand the Role of Cytokinins:**
- Cytokinins are known to regulate various developmental processes in plants, particularly in roots. They influence the size of meristems, vascular patterns, and root architecture.

4. **Cytokinins and Sieve Tube Generation:**
- Specifically, in the context of phloem, cytokinins play a crucial role in the generation of sieve tubes, which are essential for the transport of nutrients in the phloem.

5. **Impact on Vessel Elements:**
- In the early stages of plant development, cytokinins also regulate the concentration of vessel elements, further emphasizing their importance in phloem transport.

6. **Conclusion:**
- Therefore, the hormone that regulates phloem transport is **cytokinin**.

**Final Answer:**
The hormones which regulate phloem transport are cytokinin.

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