Enzymes of Sucrose Metabolism in Bryophytes

Enzymes associated with sucrose metabolism in higher plants were found in the eight species ofbryophytes examined here. Seven species of moss and a liverwort, Conocephalum conicum, were all found to have sucrose synthase, glucokinase, fructokinase, UDP-glucopyrophosphorylase, and phosphoglucomutase activities. A TP-dependent phosphofructokinase activity was found in all but Atrichum angustatum while PPi-dependent phosphofructokinase activity was found in over half the species examined. Fructose 2,6-bisphosphate, at a concentration of one micromolar, had no activating effect on the PPi-dependent phosphofructokinase activity seen in this study. In extracts from Aulacomnium palustre and Mnium affine, we found neutral invertase activity but not acid invertase. Both gametophytic and sporophytic tissues ofBryum capillare and Funaria hygrometrica were found to contain the same glycolytic enzymes; however, different levels of activity were detected in the different tissues. Collectively, these results demonstrate that the enzymes ofthe sucrose synthase pathway are present in bryophytes for feeding sucrose into their cellular metabolism.