Gibberellins are synthesised from ______.

Options

A. Acetic acid
B. Mevalonic acid
C. Tryptophan
D. Ethephon

Answer

**Step-by-Step Solution:**

1. **Understanding Gibberellins**: Gibberellins are a class of plant hormones that play a crucial role in various developmental processes in plants, including stem elongation, seed germination, flowering, and leaf expansion.

2. **Location of Synthesis**: Gibberellins are synthesized in the plastids of plant cells. Plastids are organelles found in the cells of plants and algae, which are involved in the synthesis and storage of food.

3. **Precursor for Gibberellins**: The question asks for the precursor from which gibberellins are synthesized. Gibberellins are derived from terpenes, which are organic compounds produced in the plastids.

4. **Analyzing Options**:
- **Acetic Acid**: This is not involved in the synthesis of gibberellins.
- **Mevalonic Acid**: This is a key precursor in the biosynthesis of terpenes, which are the building blocks for gibberellins.
- **Tryptophan**: This amino acid is primarily associated with the synthesis of auxins, another type of plant hormone.
- **Ethyprone**: This is involved in fruit ripening and is not related to gibberellin synthesis.

5. **Conclusion**: Based on the analysis, the correct answer to the question "Gibberellins are synthesized from ______" is **Mevalonic Acid**.

**Final Answer**: Gibberellins are synthesized from **Mevalonic Acid**.

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