There are two plants A and B with respective critical photoperiod of 13 hours and 11 hours.When they are exposed to light for a period of 12 hour, it initiated flowering in both. Which of the following conclusions is most appropriate for these plants ?

Options

A. Both plant A and B are long day plants
B. Both plant A and B are short day plants
C. Plant A is short day plant and plant B is long day plant
D. Plant A is long day plant and plant B is short day plant

Answer

To solve the question regarding the flowering behavior of plants A and B based on their critical photoperiods, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Photoperiodism**:
- Photoperiodism is the response of plants to the length of day and night, which affects their flowering.
- Plants are categorized based on their critical photoperiod into two types:
- **Long-day plants**: Require more than a certain number of hours of light to flower.
- **Short-day plants**: Require less than a certain number of hours of light to flower.

2. **Identify the Critical Photoperiods**:
- Plant A has a critical photoperiod of 13 hours.
- Plant B has a critical photoperiod of 11 hours.

3. **Analyze the Light Exposure**:
- Both plants are exposed to light for 12 hours.
- For Plant A (critical photoperiod of 13 hours), 12 hours of light is less than its requirement, but it still flowers.
- For Plant B (critical photoperiod of 11 hours), 12 hours of light exceeds its requirement, and it also flowers.

4. **Determine the Type of Plants**:
- Since Plant A can flower with 12 hours of light (even though it needs 13 hours), it indicates that it is a **short-day plant**.
- Plant B, which requires only 11 hours of light to flower but flowers with 12 hours, is a **long-day plant**.

5. **Conclusion**:
- The most appropriate conclusion is that Plant A is a short-day plant, and Plant B is a long-day plant.

### Final Conclusion:
- **Plant A is a short-day plant**, and **Plant B is a long-day plant**.