Phytohormones resposible for cell division in callus are ____ and _____.

Options

A. ABA and cytokinin
B. Gibberellin and ethylene
C. Auxin and cytokinin
D. Ethylene and cytokinin

Answer

To answer the question regarding the phytohormones responsible for cell division in callus, we can break down the information provided in the video transcript into a step-by-step solution.

### Step-by-Step Solution:

1. **Understanding Callus Formation**:
- A callus is defined as a mass of undifferentiated and rapidly dividing cells. This means that the cells in a callus do not have specialized functions and are in a constant state of division.

2. **Role of Phytohormones**:
- Phytohormones, or plant hormones, play a crucial role in regulating various aspects of plant growth and development, including cell division.

3. **Identifying Relevant Phytohormones**:
- The video mentions several phytohormones:
- **Auxin**: Promotes root formation and is crucial for cell elongation.
- **Cytokinin**: Promotes cell division and is important for shoot formation.
- **Gibberellin**: Involved in stem elongation and seed germination.
- **Ethylene**: Primarily associated with fruit ripening.
- **Abscisic Acid (ABA)**: Functions mainly as a stress hormone.

4. **Optimal Concentration for Callus Formation**:
- For callus formation, the concentration of auxin and cytokinin is critical. A balanced ratio (1:1) of auxin to cytokinin is necessary for the continuous division of cells, leading to callus development.

5. **Conclusion**:
- Based on the roles of the mentioned phytohormones, the correct answer to the question is that the phytohormones responsible for cell division in callus are **auxin** and **cytokinin**.

### Final Answer:
The phytohormones responsible for cell division in callus are **auxin** and **cytokinin**.

---