The hormone that induces apical dominance and the hormone that acts as an antagonist to this process is

Options

A. IAA and ethylene
B. NAA and Zeatin
C. IBA and NAA
D. Kinetin and BAP

Answer

To solve the question about the hormones that induce apical dominance and the hormone that acts as an antagonist to this process, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Apical Dominance**:
- Apical dominance refers to the phenomenon where the growth of the apical bud (the top part of the plant) is promoted over the growth of lateral buds. This is a common growth pattern in many plants.

2. **Identify the Hormone Inducing Apical Dominance**:
- The primary hormone responsible for inducing apical dominance is **auxin**. Auxins are a class of plant hormones that play a crucial role in the growth and development of plants.

3. **Types of Auxins**:
- Auxins have several derivatives, including:
- **IAA** (Indole Acetic Acid)
- **NAA** (Naphthalene Acetic Acid)
- **IBA** (Indole Butyric Acid)
- **BAP** (Benzyl Aminopurine)
- Among these, IAA is the most common natural auxin.

4. **Identify the Antagonist Hormone**:
- The hormone that acts as an antagonist to apical dominance is **kinetin**. Kinetin is a type of cytokinin, which can promote the growth of lateral buds, counteracting the effects of auxins.

5. **Review the Options**:
- The options given in the question are:
- IAA and ethylene
- NAA and kinetin
- IBA and NNA
- Kinetin and BAP
- From our understanding, the correct pairing is **NAA (auxin) and kinetin (antagonist)**.

6. **Conclusion**:
- Therefore, the hormone that induces apical dominance is **NAA**, and the hormone that acts as an antagonist to this process is **kinetin**.

### Final Answer:
**NAA (Naphthalene Acetic Acid) and Kinetin.**

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