Rapid growth of flowering axis in many plants is caused by

Options

A. Lower level of abscisic acid
B. Higher level of auxin
C. Higher level of gibberellin
D. Lower level of auxin.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the cause of rapid growth of the flowering axis in many plants.

2. **Identifying Plant Hormones**: The options provided include:
- Lower level of abscisic acid
- Higher level of auxin
- Higher level of gibberellin
- Lower level of auxin

3. **Analyzing Gibberellins**: Gibberellins are plant hormones known to promote stem elongation and growth. They play a crucial role in processes like bolting, which is the rapid growth and flowering of plants.

4. **Defining Bolting**: Bolting is characterized by rapid growth, cell division, and cell elongation, often leading to flowering. It can be induced by environmental factors such as long daylight or cold treatments.

5. **Role of Gibberellins in Bolting**: Higher levels of gibberellins can replace the need for long days or cold treatments to induce bolting. This means that gibberellins can trigger the rapid growth of the flowering axis even in conditions that are not typically conducive to such growth.

6. **Eliminating Other Options**:
- **Lower level of abscisic acid**: Abscisic acid is generally a growth inhibitor, not a promoter.
- **Higher level of auxin**: While auxins are important for growth, they do not specifically cause the rapid growth associated with flowering.
- **Lower level of auxin**: This would not promote growth.

7. **Conclusion**: The correct answer is that the rapid growth of the flowering axis in many plants is caused by a higher level of gibberellin.

**Final Answer**: Higher level of gibberellin.

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