Differentiation of callus requires a specific ratio of two hormones

Options

A. Auxin and gibberellin
B. Auxin and abscisic acid
C. Gibberellin and abscisic acid
D. IAA and cytokinin.

Answer

### Step-by-Step Solution:

1. **Understanding Callus**:
- Callus is an undifferentiated tissue found in plants. It is formed in response to injury or stress and can develop into various plant structures.

2. **Identifying the Hormones**:
- The question asks for the specific ratio of two hormones that influence the differentiation of callus. The options provided include:
- Auxin and Gibberellin
- Auxin and Abscisic Acid
- Gibberellin and Abscisic Acid
- Indole Acetic Acid and Cytokinins

3. **Researching Hormonal Influence**:
- Research by scientists Kug and Miller indicates that the differentiation of callus is influenced by the ratio of growth hormones, specifically auxins and cytokinins.

4. **Understanding Hormonal Ratios**:
- A high ratio of auxins (like Indole Acetic Acid) to cytokinins promotes root initiation.
- A low ratio of auxins to cytokinins encourages shoot development.

5. **Identifying the Correct Pair**:
- Based on the research, the correct pair of hormones that influence callus differentiation is **Indole Acetic Acid (an auxin)** and **Cytokinins**.

6. **Conclusion**:
- Therefore, the answer to the question is that the differentiation of callus requires a specific ratio of **Indole Acetic Acid and Cytokinins**.