Callus was grown successfully for the first time by

Options

A. White
B. Gautheret
C. Nobecourt
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding Callus**: Callus refers to a mass of undifferentiated, unspecialized cells that can be formed from plant tissues. It is often used in tissue culture and plant regeneration.

2. **Identifying the Scientists**: The question asks who successfully grew callus for the first time. The options provided are:
- A. White
- B. Godfrey
- C. Novakart
- D. Olof Peabow

3. **Researching Contributions**:
- **A. White (1934)**: Introduced vitamin B as a growth supplement in tomato root tips, which contributed to the understanding of plant tissue culture.
- **B. Godfrey (1939)**: Along with Novakart, established methods for endless proliferation in tissue culture, which is crucial for callus formation.
- **C. Novakart**: Worked alongside Godfrey in the same period to develop tissue culture techniques.
- **D. Olof Peabow**: While his contributions are significant, the specific context of callus growth is less documented compared to the others.

4. **Conclusion**: Based on the contributions of the scientists, it can be concluded that both White and the duo of Godfrey and Novakart played significant roles in the development of callus culture. Therefore, the correct answer is that all the mentioned scientists contributed to the successful growth of callus.

5. **Final Answer**: The correct option is D. All of the above.

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