Answer:
Interrupt the long winter nights with a brief period of light.
Explanation:
Long day plants, also called short night plants, flower when the dark period is equal or less than the critical period specific for the species. These plants normally flower in summers when nights are short and days are longer. Winters have a long dark period and do not support flowering in shirt night plants.
A continuous dark period is critical for flowering. A short night plant can flower in winters (having longer dark periods) if the dark period is interrupted by exposing the plant with a flash of light. To make short night plants, such as iris to flower in winters, the plant should be given short period of light after completion of critical dark period.
Sweat glands is the major function in thermoregulation.
