Photoperiodic control of growth and reproduction in non-flowering plants.

This article reviews photoperiodic responses—the regulation of plant growth and development by day length—across the plant kingdom, with a particular focus on non-angiosperm lineages such as algae, bryophytes, ferns, lycophytes, and gymnosperms. It highlights that photoperiod sensing involves the integration of light perception by photoreceptors and timing by the circadian clock, which together regulate processes including reproduction, dormancy, and metabolism. While molecular mechanisms of photoperiodism are well characterized in angiosperms like Arabidopsis and rice, evidence from genomic and transcriptomic studies reveals both conserved and distinct pathways in earlier-diverging plants, though functional studies remain limited outside flowering plants. The review emphasizes the evolutionary significance of photoperiodic regulation in plant adaptation and calls for further research into the molecular basis and interaction of photoperiodic pathways with other environmental and hormonal signals in diverse plant groups.