PGRs were first discovered in one of the following plant.

Options

A. rice
B. cotton
C. oat
D. tobacco

Answer

To answer the question, "PGRs were first discovered in one of the following plants: rice, cotton, oat, or tobacco," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term PGR**:
- PGR stands for Plant Growth Regulators, which are chemicals that influence the growth and development of plants. They can be natural or synthetic and include hormones such as auxins, cytokinins, and ethylene.

2. **Identify the First Discovered PGR**:
- The first PGR discovered was auxin, which was identified in 1928.

3. **Know the Discoverer**:
- Auxin was discovered by Dutch botanist Fritz W. Went. He isolated it from the tips of oat seedlings, specifically from a part called the coleoptile.

4. **Relate to the Given Options**:
- The options provided are rice, cotton, oat, and tobacco. Since auxin was first discovered in oat seedlings, this is the correct answer.

5. **Select the Correct Option**:
- Therefore, the correct answer to the question is "oat."

### Final Answer:
PGRs were first discovered in oats.

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