Answer:
Photoperiodism
Explanation:
The process explained in the question is called "Photoperiodism" which refers to the plants' reaction to the length of the dark and light period in a day.
When the dark period is interrupted with a certain period of artificial lighting, the plant thinks that the day had a longer period where it's "light" than it is "dark" so it gets tricked into flowering. Same concept can be applied in reverse for the plants who flower during longer periods of dark.
I hope this answer helps.
