On the Relation between the Change of Respiratory System and the Dormancy of Potato Tubers

Abstract

The present investigation was undertaken to obtain some information on the mechanism of the dormancy of potato tubers. To do this, a respiratory system which arises newly at the termination of dormancy requiring high pO2 for its activity, and the factors which cause the change of such respiratory system, were studied. Potato varieties of Irish Cobbler, D-805, Piuka-Beni, and Norin No. 1 infected with witches broom virus were used as materials. The results obtained may be summarized as follows; 1. Both from the nature of requiring relatively high pO2, and from the inhibition of O2 uptake of potato slices by 5% pO2, and acriflavine, it is reasonable to suppose that this respiratory system may be related to flavoprotein oxidase. 2. Respiratory system in potato tubers after the termination of dormancy was very similar to that of the washing old Slices which was reported by Levy and Schade (1948) and Thimann, Yocum and Hakett (1954). 3. The acidic inhibitor obtained from the dormant tubers suppressed the occurrence of a new respiratory system in washing old slices which requires the supply of high pO2. 4. Gibberellin or glutathione played an antagonistic role against the action of this acidic inhibitor. 5. When the tissue cylinders with apical buds obtained from potato tubers were washed with water for 4 days, the sprouting of the apical buds was much accelerated. This fact may be due to the disappearance of some substance from the tissue by elution, of which presence in the tissue may retard the sprouting of bud. 6. The tubers which were infected with witches' broom virus, lose their dormancies and could sprout any time. The natural gibberellin contents in such tubers were higher than those in healthy tubers. 7. Judging from the facts described above, therefore, the dormancy of the potato tubers may be controled by antagonistic actions between acidic inhibitor and gibberellin or glutathione contained in potato tubers, which in turn related to the change of respiratory system of tubers.