Light‐harvesting Pigment‐protein Complexes of the Ulvophyceae (Chlorophyta):characterization and Phylogenetic Significance¹

Photosystem II light‐harvesting complexes were isolated from a number of ulvophycean algae. Some of these light‐harvesting complexes displayed unusual features, most notably a high apparent molecular weight (ca. 58,000) when isolated by lithium doderyl sulfate polyarrylamide gel electrophoresis. Other ulvophycean light‐harvesting complexes had a low‐molecular weight (ca. 30,000). The distribution of the high‐molecular weight complex was limited to certain members of the Caulerpales and Blastophysa rhizopus (Siphanocladales). Within the Caulerpales, there were also spectral differences between the high‐molecular weight and low‐molecular weight light‐harvesting complex types. The differences in light‐harvesting complexes in the Ulvophyceae suggest that there are two lines of evolution in the Caulerpales and that Blastophysa may be an intermediate between the Siphon‐ocladales and the Caulerpales.