Multicellularity enriches the entrainment of circadian clock.

The phase response curve (PRC) of the circadian clock provides one of the most significant indices for anticipating entrainment of outer cycles, despite the difficulty of making precise PRC determinations in experiments. We characterized the PRC of the circadian clock on the basis of its phase-locking property to variable periodic pulse perturbations. Experiments revealed that the PRC changed remarkably from continuous to discontinuous fashion, depending on the oscillation amplitude.

Self-arrangement of cellular circadian rhythms through phase-resetting in plant roots.

We discovered a striped pattern of gene expression with circadian rhythms in growing plant roots using bioluminescent imaging of gene expression. Our experimental analysis revealed that the stripe wave in the bioluminescent image originated at the root tip and was caused by a continuous phase resetting of circadian oscillations. Some complex stripe waves containing arrhythmic regions were also observed.