Effect of the night in flowering in short-day plants:

If a short-day plant is kept in the dark for less than 12 hours in any place, it will not flower. Again, if kept in the dark for more than 12 hours, the plant will bloom. But even if the lights are on for a very short time in the middle of the night, the plants do not bloom because the length of the night is reduced.

Effect of the night in flowering in long-day plants:

If a long-day plant is kept in any dark place then it is seen that the flowers are not blooming when the night becomes too long.  Again, if the light is switched on for a very short time in the middle of the night, the length of the night will be broken. At that time flowers can be seen on the Long-day plants.