In plants, the circadian clock system regulates a diverse range of cellular and physiological events from gene expression and protein phosphorylation to cellular calcium oscillations, hypocotyl (seedling shoot) growth and leaf movements. The circadian system also plays a crucial role in monitoring day-length to regulate photoperiodic (day-length)-dependant flowering. On a cellular level, our lab studies the mechanism of the circadian oscillator that generates the ~24 hour rhythms. On the level of the whole plant, we are interested in understanding the adaptive significance of circadian rhythm