This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (60) Citing Articles via Google Scholar Google Scholar Articles by Küppers, U. Articles by Kremer, B. P. Search for Related Content PubMed PubMed Citation Articles by Küppers, U. Articles by Kremer, B. P. Agricola Articles by Küppers, U. Articles by Kremer, B. P.

Articles

Longitudinal Profiles of Carbon Dioxide Fixation Capacities in Marine Macroalgae ¹

Botanisches Institut der Universität, D-5000 Köln 41, Federal Republic of Germany

Fucus serratus L., Fucus spiralis L., and Fucus vesiculosus L. (Fucales, Phaeophyceae) as well as Laminaria digitata (Huds.) Lamour., Laminaria hyperborea (Gunn.) Fosl., and Laminaria saccharina (L.) Lamour. (Laminariales, Phaeophyceae) have been investigated for the distribution of enzymic CO₂ fixation capacities via phosphoenolpyruvate carboxykinase (EC 4.1.1.32) (PEP-CK) and via ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) (RubP-C) in different regions of the thalli. The maximum of PEP-CK activity is found to be confined to the growing regions of the algae, while the activity of RubP-C achieves its highest values in the entirely differentiated parts of the fronds. These findings are confirmed by the results of photosynthetic and light-independent (dark) carbon assimilation as determined by in vivo ¹⁴CO₂ fixation. The physiological significance of these differential patterns of carboxylation patterns is discussed with respect to the ontogenetic stage and the chemical constitution of the different thallus parts.