A flash of red light followed by a flash of far-red light given during the middle of the night to a short day plant, will likely

Options

A. Cause increased flower production
B. Stimulate flowering
C. Inhibit flowering
D. No effect on flowering

Answer

**Step-by-Step Solution:**

1. **Understanding Short Day Plants**: Short day plants are those that require longer nights (or shorter days) to initiate flowering. They typically flower when the duration of darkness exceeds a certain critical length.

2. **Role of Light in Flowering**: Light quality, particularly the wavelengths of light, plays a crucial role in the flowering process of plants. Phytochromes are the photoreceptors in plants that detect light and are sensitive to red (660 nm) and far-red (730 nm) light.

3. **Effect of Red Light**: When a flash of red light is given to a short day plant during the night, it can temporarily disrupt the dark period. This is because red light can be absorbed by phytochromes, which can lead to a physiological response in the plant.

4. **Effect of Far-Red Light**: Following the red light, a flash of far-red light is given. Far-red light can convert the phytochrome that was activated by red light back to its inactive form. This means that the effect of the red light is negated by the far-red light.

5. **Conclusion**: Since the red light initially disrupts the dark period but is followed by far-red light, the overall effect is that the plant does not receive a long enough uninterrupted dark period to trigger flowering. Therefore, the short day plant will not flower as a result of this treatment.

6. **Final Answer**: A flash of red light followed by a flash of far-red light given during the middle of the night to a short day plant will likely have no effect on flowering.

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