1963 Volume 76 Issue 904 Pages 374-380
1. The behaviour of irritable reaction of the parenchymatous cells of the pulvinus was made clear by observing it directly under the microscope by means of electric stimulation. As the symptoms of excitement, rapid vacuole contraction, the deformation of the cell and the diminution in cell volume occurred by stimulation. Sometimes the diminution of cell volume was slight or scarcely observed. These responses were seen in the parenchymatous cells of both the upper and lower halves of the pulvinus alike. This reaction was quite reproducible. If the cells, however, received dratsic stimulation, irreversible reaction occurred.
2. The oscillating phenomenon was demonstrated in the recovery course of the leaf movement. This oscillation movement may be caused by the counteraction of the upper and lower halves of the pulvinus.
3. Based on these findings, some interpretation on the machanism of the seismonastic leaf movement was presented.