Structure of the Photoreceptor System

Zusammenfassung

Critical aspects in algal photoreception are: 1) the location and structure of the photoreceptor system; 2) the composition of the photoreceptor pigments; and 3) the mechanism(s) of photoreception. For nearly 100 years [Engelmann, 1982a,b], the photoreceptor was thought to be the stigma (“eyespot”, “Augenflecke”) [see reviews by Dodge, 1973; Sedova, l977; Ettl, 1980; Massjuk and Posudin, 1991b]. This belief was supported indirectly by its presence in the coloured motile vegetative and reproductive cells of algae, its disappearance when the algae was kept for extended periods in darkness, and its restoration when exposed to light [Kivic and Vesk, 1972, 1974].