circadian-rhythms
Circadian rhythms are internal biological oscillations that repeat approximately every 24 hours, coordinating cellular and physiological processes in alignment with the day-night cycle. In plants, these rhythms regulate critical functions such as photosynthesis, flowering time, stomatal opening, and stress responses, ensuring each process occurs at the optimal time of day. Understanding plant circadian clocks offers insights into how plants adapt to seasonal changes and environmental conditions, with implications for improving crop productivity and resilience.
open_in_new WikipediaPubMed · 2026-04-15
Plants have internal clocks that don't always tick at exactly 24 hours — and that turns out to be a feature, not a bug. This review synthesizes recent evidence showing that clocks running 2+ hours fast or slow are widespread in plants and can help them thrive in new environments.
Endogenous circadian cycles differing from 24 hours by 2 or more hours are prevalent across the green lineage, overturning the assumption that near-perfect 24-hour clocks are required for fitness.
Rather than being uniformly disadvantageous, off-period clocks can confer adaptive advantages by enabling plants to exploit a wider range of environmental niches and life history strategies.
The same circadian period change can produce different plant responses depending on which photoperiodic output pathways are active, providing a flexible mechanism for fine-tuned local adaptation.