INTERCELLULAR ASSIMILATE TRANSLOCATION IN GRACILARIA-CORNEA (GRACILARIACEAE, RHODOPHYTA)

Assimilate translocation has been identified and characterized in Grac ilaria cornea under different conditions. Carbon fixation and transloc ation were carried out by inserting the base part of the thallus into a bicarbonate labeled solution in seawater and exposing its upper part to the air (open system) or to a non-labeled solution above a rubber septum (closed system). After a pulse-chase treatment in the light, th ree separate sections of each thallus were extracted by DMF (high mole uclar weight photosynthates) or by ethanol (low molecular weight). The results indicate a high rate of active photosynthate translocation wh ich is directly related to inorganic carbon gradients in the thallus, and probably also to sugar gradients in the thallus. Translocation par ameters of Gracilaria cornea are lower than of brown algae, as Gracila ria does not contain specific translocation tissues.