In short day plants, flowering is inhibited by

Options

A. Interruption of dark by white or red light
B. Dark interruption by far red light
C. Dark interruption by red light followed by far red light
D. Not possible

Answer

### Step-by-Step Solution

1. **Understanding Short Day Plants**:
- Short day plants, also known as long night plants, require a longer duration of darkness (night) to initiate flowering. They typically flower when the night length is equal to or greater than a specific critical period.

2. **Role of Darkness**:
- The flowering process in these plants is influenced by the length of the dark period. If the dark period is shorter than the critical length, flowering will not occur.

3. **Interruption of Darkness**:
- The flowering in short day plants can be inhibited if there is an interruption during the dark period. This interruption can occur due to exposure to light.

4. **Types of Light Interruption**:
- The types of light that can interrupt the dark period include white light and red light. When these lights are flashed during the night, they can disrupt the necessary long dark period required for flowering.

5. **Evaluating the Options**:
- **Option 1**: Interruption of dark by white or red light - This is correct because it disrupts the necessary long dark period.
- **Option 2**: Dark interruption by far red light - This is incorrect as far red light does not inhibit flowering in short day plants.
- **Option 3**: Dark interruption by red light followed by far red light - This is also incorrect for the same reason as option 2.
- **Option 4**: Not possible - This is incorrect as it is indeed possible to inhibit flowering in short day plants.

6. **Conclusion**:
- The correct answer is **Option 1**: Interruption of dark by white or red light inhibits flowering in short day plants.