Abstract
The circumnutation of a rice root under dark condition was taken by a highly sensitive camera, a new super-HARP camera. A rice root showed regular rhythmic movement with fixed angle. When treated with Al (5 mM AlCl3), the rotation angle of the root tip was drastically decreased and then the movement was resumed again, whereas the root elongation rate was kept constant. With the increase of Al concentration, the cycle-fading period became shorter. This is the first report to show that an Al treatment ceased the rotation movement of the root but not elongation.