Photoperiodism A biological response to the length and timing of day and night, making it possible for an event to occur at a particular time of year.

• 光周期诱导：植物只需要一定时间适宜的光周期处理，以后即使处于不适宜的光周期下，仍然可以长期保持刺激的效果，这种现象称为光周期诱导。