Abstract
Precise timing of flowering in plants is critical for their growth and reproductive processes. One factor controlling flowering time is the cycle of light and darkness within a day, known as the photoperiod. Plants are classified into long-day, short-day, and day-neutral plants based on light requirements for floral initiation. Although the molecular mechanisms that govern this differentiation remain incompletely understood, studies have consistently shown that the circadian clock plays a central role in regulating photoperiod response across diverse plant species. However, there is a scarcity of reviews describing the regulatory network linking the circadian clock with photoperiodic flowering. This review summarizes that regulatory network, focusing on the distinct roles of clock genes in long-day and short-day plants. We also discuss the strategies of clock gene mutations contributing to geographic variation in long-day and short-day crops.
