METABOLIC CONVERSION OF EXOGENOUS C-14 ASPARTATE AND C-14 GLUTAMATE IN THE DARK BY FUCUS-SERRATUS L

The rates of uptake of exogenous L[U-C-14] aspartate and glutamate int o tissues of vegetative growing tips of Fucus serratus and their metab olism were studied in the dark. In these non-photosynthetic conditions , aspartate was fixed and metabolically converted more rapidly than gl utamate. Radioactivity from C-14-aspartate was principally transferred into glutamate. On the other hand, metabolism of absorbed C-14-glutam ate was very slow and its rate did not increase during incubation time , but produced more diversified soluble radioactive compounds. Thus in F. serratus, glutamate principally seems to be in the dark more a tem porary (CO2)-C-14 storage product coming from beta-carboxylation than a rapidly turned over intermediate.