Question

In short day plant, flowering does not occur

• A. When intermediate light is given red $\to$ far red $\to$ red
• B. When light period is interrupted by a flash of far light
• C. When light period is interrupted by a flash red $\to$ far light
• D. All of the above

Answer 1

The correct option is A When intermediate light is given red $\to$ far red $\to$ red

Short day plants flower, when the length of daylight falls below a certain critical level. A short day plant requires a minimal length of uninterrupted darkness in each 24 hour period before floral development can begin. It has been determined experimentally that a short day plant does not flower if a dark period is interrupted by a brief exposure to a red light (660-665 nm wavelength. The inhibitory effect of the red light can be overcome by the subsequent exposure to the far red light (730-735 nm wavelength. However, if the light period is interrupted with red light, the flowering is not inhibited.