Abstract
In order to obtain some informations of the physiological nature of the sprout inhibiting substance in the resting potato tubers, the present investigation was undertaken. The sprout inhibiting substance was extracted from the dormant potato tubers according to the technique of Hemberg. The experimental results may be summarized as follows. This substance has an activity to inhibit the auxin-induced growth of Avena seedlings and its activity was decreased by the treatment with active carbon. Although this substance maintains its activity even by boiling in 1/10 N-HCI solution for one hour, but lost it activity remarkably by boiling in 1/10 N-KOH solution for the same length of time. On the other hand, when the disks of tuber tissues were treated with this substance, the water permeability of potato cells decreased markedly. It may be assumed from the results mentioned above that the sprout inhibiting substance contained in the dormant potato tubers may also inhibits the rate of water uptake by potato parenchym cells.
