Abstract
The flower of Portulaca generally opens early in the morning in response to a temperature rise and a light exposure. We had reported that the light irradiation could induce the flower-opening of Portulaca hybrid alone at 30C and that the Plasma membrane (PM) H+-ATPase activity in the petal increased during flower-opening process. In this study, we examined the effect of the timing of light irradiation on the flower-opening and the enzyme activity using the plants cultivated under 12L (8:00-20:00, 30C) /12D(20:00-8:00, 25C) condition. At 30C, the flower-opening never began before 3:00 regardless of the timing of light irradiation and when the dark period was less than 4 hours, the flower did not open completely. On the other hand, the activity and amount of the enzyme increased from 2:00 to 5:00. We now investigated whether the timing of light irradiation and inhibitors of flower-opening influence the behavior of the enzyme.
