SEASONAL-CHANGES IN THE STARCH CONTENT, AND ASSOCIATED ANABOLIC AND CATABOLIC ENZYMES, IN THE ROOTS ELF THE PERENNIAL WEED, EUPHORBIA-ESULA

Starch is the principal carbohydrate reserve in the persistent roots o f the perennial weed leafy spurge (Euphorbia esula). It increases duri ng the autumn and early winter months, and is stored in the cortical c ells and rays of the secondary xylem. There is a poor temporal correla tion between the activities of several of the major enzymes associated with starch synthesis, and the deposition of the reserve itself. Bett er correlations exist between the mobilization of starch and the appea rance of amylases. Two forms of alpha-amylase with different molecular masses, and four different pI forms are present in the roots. The pea ks of starch phosphorylase activity are similar to those of the amylas es, although a role for this enzyme in starch synthesis is possible.