Abstract
Lemna plants (duckweeds, monocotyledonous plants) have suitable traits for analysis on photoperiodic responses. The Hillman's skeleton photoperiod experiments using L. paucicostata 6746 were reported in 1964 and they become the monument directly showing the role of the circadian clock in the photoperiodic time measurement. Furthermore, two species in the same genus show opposite photoperiodic responses; L. gibba G3 and L. paucicostata 6746 are long-day- and short-day plants, respectively. In order to approach molecular mechanisms of the photoperiodic flowering, we have begun the molecular analysis using the Lemna plants since 2001. Through experimental trials for the "new" materials, we have found various traits that would be suitable for molecular analyses. We will present our attempts to develop reporter and effector systems, photoperiodic experiment systems, and to establish pure lines for genetic analysis. We will also discuss possibilities of these plant species as a model for general plant studies in laboratory.
