Die Saccharase im Stoffwechsel der Kartoffelknolle

Abstract

Summary Invertase in metabolism of potato tuber III. Invertase activity and hexoses content in the mother tuber after planting in soil Sprouting mother tubers were analysed for content of dry matter, sucrose, reducing sugars and invertase activity during growing in soil. Sucrose content remained constant, but content of hexoses increased and gradually lead to steady state conditions (Fig. 1 u. 2). As the activity of the “basal invertase” as the activity of “total invertase” (after destroing the endogenous inhibitor) calculatid per g fresh weight and per g protein at first increased and than after reaching a maximum decreased (Fig. 1 and 3). The increase of enzyme activity was lead back to a synthese of enzyme. In the various experiments with mother tubers negative correlations were found between content of dry matter and hexoses. A decrease of dry matter content of 1 % corresponded an increase in hexosescontent of about 0,1-0,12 % (absolute). The hexoses were accumulated in the rate as the dry matter was exported to the growing plant. From this finding the conclusion was drawn, that hexoses were produced to maintain the osmotic pressure of the cells so that the metabolism of mother tuber was generally possible in spite of translocation of nearly all soluble substances. As the hexoses content the invertase synthesis must be regulated by the export process, but these connections shall be discuss in the following paper.