Abstract
Some flowers open in the morning. And some ones do in the evening. Linne proposed the idea of the floral clock which was made up of various kinds of flowers opening at different time each other. Recently, variation of the timing among closely related plant species in the field has been studied on aspect of the differentiation of reproductive timing. Here, we present chronobiological features of flower opening in Arabidopsis thaliana. The plant opens flower in the morning, but the detail is unknown. Then, we examined it under diurnal light/dark cycle. The petal began the expansion when lamp started illumination. Then, it opened completely for 3 hours in the light. We examined whether the rhythm continued in light without the daily dark periods. Observation of four days in light showed the rhythm with 23 hours period. The period was not changed in low or high temperature. In addition, the rhythm was entrained by external light/dark cycles. These properties are essential to circadian rhythm. Thus, Arabidopsis petal movement is under circadian clock. The chronobiological properties will arrow us to know signal transduction of the movement under circadian clock.
