Abstract
In this research, the folding and unfolding manner of small-type petunia flowers was observed by using CCD video camera with timing control. The tensile tests for petals and petal cylinders were carried out. The change of the strain energy absorbed in petal ribs during unfolding of flower was also examined by using the paper model of flowers. It was found that the Young's modulus of petal ribs is much greater than that of petals. Petunia flower deploys quickly for 3〜4 hours following the first slow deployment for 16〜19 hours. And then, it deploys with relatively high speed after the stagnation of 12〜14 hours. The release of strain energy absorbed in the reinforcement axes in a petal cylinder may contribute unfolding of the flower.
