Abstract
Duckweeds (family Lemaceae) suit for physiological experiments in the laboratory because of the tiny plant bodies, rapid growth rates, strictly controllable environments under aseptic conditions, and so on. They also draw attention as a material for bioremediation. In 2009, a genome project for Spirodela polyrhiza (giant duckweed) began as a program in DOE JGI. Its small genome size (~150 Mbp) is a marked trait for the genome sequencing. However, physiological experiment techniques using S. polyrhiza are not developed especially in the study of the biological clock. Plants in Lemna genus instead have been widely used in physiological studies of photoperiodic flowering, circadian rhythms and so on. We analyzed clock-related genes from Lemna plants and also developed a convenient monitoring system of bioluminescent circadian rhythm that is introduced with a particle bombardment method. We then attempted to use S. polyrhiza for the study of biological clock. We first performed physiological characterization of this plant under a number of experimental conditions. We also tried to apply the bioluminescence reporter system to the monitoring circadian rhythm of S. polyrhiza.
