PHOTOSYNTHESIS AND METABOLISM IN MARINE ALGAE: VI. THE UPTAKE AND INCORPORATION OF S35-SULPHATE IN FUCUS VESICULOSUS

Abstract

The uptake and fixation of S³⁵-labelled sulphate in the rockweed Fucus vesiculosus has been examined using direct chromatography of ground tissue as well as conventional techniques. The uptake of sulphate, unlike that of carbonate, is complex and not directly related to internal requirement. Both the uptake and fixation of sulphate are increased by light. Sulphate appears to penetrate into the thallus with difficulty: cut tissue took up sulphate much faster than undamaged tissue, the rate of uptake being roughly proportional to the area of cut surface, not to the area of intact surface. Frozen and ground tissue retained its ability to convert sulphate into organic forms for a short time. An active exchange of the sulphate portion of the sulphated polysaccharide, fucoidin, was detected. The incorporation of S³⁵into fucoidin was 20 to 600 times greater than that of C¹⁴, depending on the duration of the experiments.