PRODUCTS OF PHOTOSYNTHESIS IN CAULERPA SIMPLICIUSCULA (CHLOROPHYCEAE)1

The kinetics of carbon flow through various metabolites of Caulerpa simpliciuscula C. Ag., a siphonaceous green alga, are described. The pattern of C fixation in this alga differs from those observed in higher plants and other green algae in a number of respects. After 40 min incubation, soluble β-linked polyglucans are the most important labelled carbohydrates. Sucrose, although delectable, is never a major recipient of label and does not label until after other oligosaccharide fractions. The sugar monophosphates contain a large proportion of the ¹⁴C assimilated even after 40 min and behave not only as metabolic intermediates, but also as storage pools. The pattern of ammo acid labelling resembles that reported for other species of green algae in that alanine becomes labelled most rapidly, followed by glycine, and much later by glutamate, glutamine and asparagine. These labelling patterns are discussed in the light, of what is known of patterns of C flow in other algae.