What Causes Photoperiodism?

Hint: Photoperiodism is a kind of physiological response of an organism to the duration of night or dark. It occurs both in plants and animals. Example flowering in certain plants takes place at a particular season. It is a kind of developmental response.

Complete answer:
The developmental response of the plant towards the duration of day and night is believed to take place due to the photoreceptor proteins like phytochromes and cryptochromes. These proteins sense the changes in season or light and transmit the signals to the flower. The phytochromes sense the red-light wavelength and trigger the growth of the plant. The cryptochromes respond to the blue light. It is responsible for maintaining the circadian rhythm in plants. Both these proteins are responsible for the photoperiodic response. Certain hormones are also responsible for the response of plants towards the photoperiod.

Note:
-Short Day Plants (SDP): Short-day vegetation normally requires a light period of but 12 hours i.e. 8-10 hour and a continuous dark duration of about 14-16 hour for subsequent flowering. Most of the wintry weather flowering plants belong to the present category e.g. Xanthium, Dahlia, sugarcane, rice, potato.
-Long Day Plants (LDP): Long day flowers require a light length of 14-16 hour for subsequent flowering. plants. E.g. Spinach etc.
- Day Neutral Plants: This vegetation flower altogether for the duration of photoperiods and may additionally blossom in the course of the year. Examples are tomato, cucumber, etc. This vegetation produced greater fruits as they require regular conditions.
Photoperiodic reactions can be reasonably predicted, but temperature, nutrition, and other environmental factors also modify an organism's response.