Which of the following is not a function of cytokinin ?

Options

A. Delay in senescence
B. Breaking seed domancy
C. Promoting bud dormancy
D. Counteracting to apical dominance

Answer

To determine which of the following is not a function of cytokinin, we will analyze each option provided in the question. Cytokinins are a class of plant hormones that play various roles in plant growth and development.

### Step-by-Step Solution:

1. **Identify the Functions of Cytokinins:**
- Cytokinins are known to promote cell division and growth in plants. They are involved in various physiological processes.

2. **Evaluate Each Option:**
- **Option 1: Delay Senescence**
- Cytokinins are known to delay senescence (aging) in plants by promoting cell division and growth. Therefore, this option is a function of cytokinins.

- **Option 2: Breaking Seed Dormancy**
- Cytokinins play a role in breaking seed dormancy, allowing seeds to germinate and grow. Thus, this option is also a function of cytokinins.

- **Option 3: Promoting Bud Dormancy**
- This option is incorrect as cytokinins do not promote bud dormancy. Instead, they help in breaking dormancy. Gibberellins are the hormones that can promote dormancy in buds. Therefore, this is the correct answer as it is not a function of cytokinins.

- **Option 4: Counteracting Apical Dominance**
- Cytokinins can counteract apical dominance by promoting lateral bud growth. This means that they help in branching by reducing the dominance of the main shoot. Hence, this option is also a function of cytokinins.

3. **Conclusion:**
- After evaluating all options, the correct answer is **Option 3: Promoting Bud Dormancy**, as it is not a function of cytokinins.

### Final Answer:
**Option 3: Promoting Bud Dormancy**