Abscisic acid acts as an antagonist to______

Answer

**Step-by-Step Solution:**

1. **Identify the Hormones Involved**: The question asks about the role of abscisic acid (ABA) in relation to other hormones. The primary hormone it acts against is gibberellic acid (GA).

2. **Understand the Functions of Abscisic Acid**: Abscisic acid is known for its role in inhibiting growth. It promotes dormancy in seeds, buds, and tubers, which means it prevents these structures from growing or developing further.

3. **Understand the Functions of Gibberellic Acid**: In contrast, gibberellic acid promotes growth and development. It helps in breaking dormancy in seeds and stimulates the synthesis of RNA and proteins, which are essential for growth.

4. **Analyze the Antagonistic Relationship**: The antagonistic relationship between ABA and GA can be summarized as follows:
- Abscisic acid inhibits growth, while gibberellic acid promotes it.
- ABA promotes dormancy, whereas GA overcomes dormancy.
- ABA inhibits the synthesis of RNA and proteins, while GA promotes their synthesis.
- ABA causes abscission (the shedding) of flowers and fruits, while GA promotes their development.

5. **Conclusion**: Based on the functions and the antagonistic relationship, we conclude that abscisic acid acts as an antagonist to gibberellic acid.

**Final Answer**: Abscisic acid acts as an antagonist to gibberellic acid.

---