On the Relativity between Copper Enzyme and Dormancy of the Potato Tubers

Abstract

The present investigation was undertaken in order to obtain some information on the dormancy of the potato tubers from the view points of certain enzyme activities. To do this, the effects of some enzyme inhibitors, such as, KCN and diethyldithiocarbamate (Dieca), on the O₂ uptake by the potato disks were studied. The results obtained may be summarized as follows : 1. The inhibition of O₂ uptake by potato disks in the presence of Dieca was more pronounced during the rest period than that during the sprouting period of the tubers. 2. Although the O₂ uptake by the potato disks was inhibited by the application of KCN during the rest period, as well as during the sprouting period, such inhibitioh was much significant during the sprouting period of the tubers. 3. With regard to the O₂ uptake by the potato disks of which tubers were treated with Bervitan K to inhibit their sprouting, similar results were obtained as shown in 1 and 2. 4. The activity of tyrosinase in the homogenate which was obtained from the apical part of and cortex of the tubers was higher during the rest period as compared to that obtained after the rest period. 5. Indoleacetic acid (IAA) seems to be inactivated by potato tyrosinase in the presence of catechol and air. 6. It seems quite probable to assume that the copper enzyme, presumably tyrosinase in association with IAA may play some physiological role on the dormancy of the potato tubers.