During seed germination, apical hook formation and elongation of the axis is associated with

Options

A. Cytokinin
B. ABA
C. Gibberellins
D. Ethylene

Answer

**Step-by-Step Solution:**

1. **Understanding Seed Germination**: Seed germination is the process by which a seed develops into a new plant. This process involves several physiological changes, including the formation of structures like the apical hook and elongation of the plant axis.

2. **Identifying the Role of Hormones**: Various phytohormones (plant hormones) play roles in seed germination. The main hormones to consider are ethylene, abscisic acid (ABA), gibberellins, and cytokinins.

3. **Ethylene's Role**: Ethylene is known to be involved in breaking seed dormancy and promoting germination. It facilitates the formation of the apical hook and the elongation of the plant axis during the early stages of seedling development.

4. **Examining Other Hormones**:
- **Abscisic Acid (ABA)**: This hormone generally inhibits seed germination and promotes dormancy, making it unlikely to be associated with apical hook formation or axis elongation.
- **Gibberellins**: While gibberellins promote seed germination and stimulate the production of enzymes that mobilize food reserves, they are not specifically responsible for apical hook formation.
- **Cytokinins**: These hormones also promote germination and can help overcome dormancy, but they do not specifically induce apical hook formation or axis elongation.

5. **Conclusion**: Based on the roles of these hormones, ethylene is the hormone primarily associated with the formation of the apical hook and elongation of the axis during seed germination.

**Final Answer**: The hormone associated with apical hook formation and elongation of the axis during seed germination is **ethylene**.

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