Which plant hormone was discovered as kinetin

Options

A. ABA
B. Ethylene
C. Auxin
D. Cytokinin.

Answer

To answer the question "Which plant hormone was discovered as kinetin?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Kinetin**:
- Kinetin is an adenine derivative, specifically an aminopurine. It was first isolated from autoclaved herring sperm DNA.

2. **Isolation of Kinetin**:
- The isolation of kinetin was done by scientists named Skoug and Miller. They identified it as a factor that promotes cell division.

3. **Identifying the Hormone**:
- Since kinetin is an adenine derivative and is known for its role in promoting cell division, it is classified under a group of hormones known as cytokinins.

4. **Role of Cytokinins**:
- Cytokinins are plant hormones that promote cell division, nutrient mobilization, and delay leaf senescence (aging). They are naturally found in regions of plants where rapid cell division occurs.

5. **Conclusion**:
- Based on the information gathered, the plant hormone that was discovered as kinetin is **cytokinin**. Therefore, the correct answer is option number 4.

### Final Answer:
The plant hormone that was discovered as kinetin is **cytokinin**.

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