Circadian Rhythm: Phase Response Curve and Light Entrainment

The circadian clock responds to light signals and therefore participates in the plant's daily response to light. The phase response curve (PRC) is typically used in the study of chronobiology to detect the effect of various environmental cues on a given circadian rhythm. In this chapter we describe protocols on measuring the setting of the light pulses at different times of a day, the measurement of circadian rhythm, and the calculation of phase shift in response to light pulses. The promoter:luciferase reporter was used to provide fine rhythmic traces and the subsequent circadian parameters of mathematical analysis. A classical PRC assay to light pulses is the key experimental basis for determining the signal components of resetting the circadian clock.