Abstract
The flower of Portulaca is ephemeral and generally opens early in the morning. It is well known that flowers of Portulaca open in response to a temperature rise and a light exposure, but the little is known of the cellular and molecular mechanisms behind the enviromental control. We established the flower-opening system using with isolated flower buds. In this system, blue light (470 nm) is more effective on the induction of flower opening than red light (660 nm) at 50 μE. The longitudinal elongation of epidermal cells of the petals was enhanced by a temperature rise and a light irradiation. CytochalasinB, DPI, BrefeldinA, IAA and K-252a inhibited the flower opening and the longitudinal elongation of epidermal cells without the inhibition of the fresh weight increase. During the flower-opening process, the vanadate-sensitive ATPase activity in crude microsome fraction of the petal increased about 1.5 times, on the basis of protein.
