On the Relationship between the Phosphate Composition of Potato Tuber and its Dormancy

Abstract

The present investigation was undertaken in order to obtain some information on the mechanism of the dormancy in potato tuber. To do this, changes of phosphate composition in potato tuber upon its emergence and also in tuber slices which were subjected to various incubation treatments, were investigated. The results btained may be summarized as follows. Change in phosphate composition of sprouting potato tubers especially in the ratio of labile (readily hydrolysable) P to organic P, was larger than that in dormant tubers. As a result of incubating treatment in the solution containing inhibitor-β, the phosphate composition of the slice changed in different ways according to the kind of treatments; inhibitor-β brought about the decrease in the ratio of labile P to organic P, while the application of gibberellin or glutathione having antagonistic action to inhibitor-β, causes the increase in this ratio. It seems, therefore, to be reasonable to assume that the dormancy of potato tubers may be controlled by antagonistic actions between inhibitor-β and native gibberellin or glutathione contained in the tuber. In this case, change in respiratory system of the tuber upon sprouting may participate in the termination of dormancy of potato tuber by synthesizing energy-rich phosphate compounds.