Relationship between Starch Content and Activity of Starch Synthase and ADP-glucose Pyrophosphorylase in Tuberous Root of Sweet Potato

Abstract

Relationship between starch content and the activity of starch synthase and ADP-glucose pyrophos-phorylase in tuberous roots of sweet potato was investigated using several cultivars. No correlation was observed between soluble starch synthase activity and dry matter content and between total starch synthase activity and starch content of tuberous root. ADP-glucose pyrophosphorylase activity per fresh weitht of tuberous root correlated positively to starch content of cultivars. And the changes in the activity of this enzyme during growth were similar to those in the starch content. From these results, it is thought that ADP-glucose pyrophosphorylase is one of the key enzymes in starch accumulation in tuberous root of sweet potato.