Question

Write three differences between short day and long day plants.

Answer 1

• Short day plants are those plants that flower when exposed to day lengths shorter than the critical point whereas, long day plants are those plants that flower when exposed to day lengths longer than the critical point.
• Short day plants require continuous dark period whereas, the length of the light period is more critical for long day plants.
• Short day plants do not flower if dark period is interrupted by a flash of light whereas, flowering is stimulated in long day plants, if the dark period is interrupted by a flash of light.
• In short day plants gibberellic acid (GA) does not induce flowering except in few plants like, balsam whereas, GA induces flowering in most of the long day plants.
• Short day plants are also called long night plants whereas, long day plants are also called short night plants.
• Short day plants normally flower in the early spring or autumn whereas, long day plants normally flower in the spring or early summer.