Chloroplast Pigments in Selected Marine Chaetophoraceae and Chaetosiphonaceae (Chlorophyta): The Occurrence and Significance of Siphonaxanthin

Abstract

Analysis by TLC of the chloroplast pigments in several members of the marine Chaetophoraceae and Chaetosiphonaceae reveals the presence of siphonaxanthin in 10 of 16 spp. [Acrochaete repens Pringsheim, Bolbocoleon piliferum Pringsheim, Endophyton ramosum Gardner, Entocladia codicola Setchell et Gardner, E. viridis Reinke, E. wittrockii Wille, Ochlochaete hystrix Thwaites, Phaeophila dendroides (Crouan) Batters, Pilinella colifornica Hollenberg, Pringsheimiella scutata (Reinke) Marchewianka, Pseudendoclonium submarinum Wille, P. fucicola (Rosenvinge) Nielsen, Pseudodictyon geniculatum Gardner, Pseudulvella applanata Setchell et Gardner, Blastophysa rhizopus Reinke, Chaetosiphon moniliformis Huber]. The other chloroplast pigments are typical of the Chlorophyta, except that 4 of the siphonaxanthin-containing taxa do not possess lutein. Species lacking siphonaxanthin are found only in mid- to upper-intertidal habitats, while those lacking lutein occur only in the subtidal. Species having both pigments occupy intermediate, relatively wide-ranging habitats. The presence or absence of siphonaxanthin in a given species reflects both the ecological and the systematic positions of that species. The ability to synthesize siphonaxanthin, and its esterified derivative, siphonein, is restricted to deep-water green algae referred to the class Ulvophyceae and to certain scaly green monads (Prasinophyceae). This supports the ancestry of the Ulvaphyceae from flagellates similar to present-day Prasinophyceae. Differences in siphonaxanthin and siphonein profiles correlate with other characters to identify major groups within the Ulvaphyceae.