Bioassay for gibberellin is

Options

A. Avena curvature test
B. Seed dormancy test
C. Dwarf maize test.
D. Green leaf test.

Answer

### Step-by-Step Solution:

1. **Understanding Bioassays**: A bioassay is a scientific experiment that determines the concentration or potency of a substance by its effect on living cells or tissues. In this case, we are focusing on gibberellins, which are plant hormones that promote growth.

2. **Identifying the Options**: The options provided for the bioassay of gibberellin are:
- Avena curvature test
- Seed dormancy test
- Dwarf maize test
- Green leaf test

3. **Analyzing Each Option**:
- **Avena Curvature Test**: This test is primarily used for auxins, not gibberellins.
- **Seed Dormancy Test**: This test assesses the dormancy of seeds and is not specific to gibberellin activity.
- **Dwarf Maize Test**: This test is specifically designed to measure the effects of gibberellin. It is based on the principle that gibberellin promotes the elongation of internodes in maize plants.
- **Green Leaf Test**: This test is used to determine the presence of chlorophyll and does not measure gibberellin activity.

4. **Conclusion**: Among the options, the **Dwarf Maize Test** is the most appropriate bioassay for gibberellin because it directly measures the elongation effects that gibberellin has on the internodes and leaf length in maize plants.

5. **Final Answer**: The correct answer is **Dwarf Maize Test**.