Cytokinins which have specific effect in cytokinesis are modified forms of

Options

A. Cytosln
B. Adenine
C. Guanine
D. Thiamine

Answer

**Step-by-Step Solution:**

1. **Understanding Cytokinins**: Cytokinins are a class of plant hormones that promote cell division (cytokinesis) in plant roots and shoots.

2. **Isolation of Cytokinins**: The first cytokinin to be discovered was kinetin, which was isolated from herring sperm DNA. It was found to have the ability to promote cytokinesis.

3. **Chemical Structure**: Kinetin is a modified form of a purine, which is a type of nitrogenous base found in nucleic acids.

4. **Identifying the Purine**: The specific purine from which kinetin is derived is adenine. Thus, cytokinins are modified forms of adenine.

5. **Natural Occurrence**: While kinetin is a synthetic compound, natural cytokinins such as zeatin are found in plants, particularly in corn kernels and coconut milk. These natural cytokinins also promote cell division.

6. **Conclusion**: Therefore, the answer to the question is that cytokinins, which have a specific effect in cytokinesis, are modified forms of adenine.

**Final Answer**: Cytokinins, which have specific effects in cytokinesis, are modified forms of adenine.

---