Abstract
Plant circadian clock is synchronized to daily changes in light and temperature. We monitored the responses of the circadian gene expression to light pulses by introducing the bioluminescent reporter system to Lemna plants (duck weeds).
In 1960, Hillman analyzed the photoperiodic flowering of the shortday plant Lemna paucicostata in response to "skeleton photoperiods". Skeleton photoperiods are composed of two light pulses with a 24-h period in prolonged darkness. He found the bistability phenomenon that plants recognized the intervals between the pulses as day or night depending on the timing of the first pulse. Recently, Ito-Miwa and Oyama measured the circadian gene expression under skeleton photoperiods by the bioluminescent reporter system, and directly observed the bistability of the rhythm. In order to analyze the mechanisms of the circadian clock system to light pulses, we monitored responses of the circadian gene expression to various light pulses. We also measured the circadian bioluminescent reporter activities at the single cell level. In addition, we observed several clock deficient cells.
