Photoperiodism is a term in biology for the way a plant or animal reacts to the amount of light it gets at a time, including flowering or not flowering.
An example of photoperiodism is when a plant doesn't bloom during the increased darkness of winter time.
Biol. the behavioral or physiological reaction of an organism to variations in the duration of light, as, in plants, by flowering or ceasing to flower, or, in certain animals, by changing the daily cycle of activities
An organism's response or ability to respond to changes in photoperiod.