Entrainment of Cellular Circadian Rhythms in Lactuca sativa L. Leaf by Spatially Controlled Illuminations

Abstract

Plant circadian system works autonomously and responds to various environmental information in cellular level. Conventional studies on controlling of the plant circadian system, however, have not thoroughly considered in cellular level yet. In this study, we investigated spatiotemporal dynamics of cellular circadian rhythms of clock gene CCA1 in leaves that were controlled by the projector lightings in a transgenic lettuce strain AtCCA1::LUC using a bioluminescence imaging. We have succeeded to control the cellular circadian rhythms in the both case of LCD and laser projectors with 24 or 26 h periods of light-dark cycles. Although light intensity of the laser projector was very small to a required light intensity for growth of lettuces, the circadian rhythm was entrained with high sensitivity for illumination. Our results motivate experimental and theoretical studies of circadian control and development for the highly functional lighting technology in plant productions.