Abstract
We found that flower stalk of Arabidopsis thaliana (Columbia) exhibits circumnutation with exaggerated movement in dark condition. To analyze this phenomenon, we constructed video-monitoring system to obtain the views from the above and the side of the plants. Obtained images were used to calculate the frequency of the circumnutation as well as the curvature and the growth rate of the flower stalk, which were used to characterize the circumnutation under different conditions. High frequency circumnutation with small curvature was observed in flower stalks of Arabidopsis plants grown in light condition, and when they were transferred to dark condition, the flower stalk started to circumnunate with huge curvature and low frequency 12 hr after transition. If exposed to illumination during this movement, the curvature remained large, but the frequency was increased. The manner of this reaction to the transition of the light condition differs in different Arabidopsis ecotypes.
