| Abstract: | Abstract— 1. R-II is a u.v. induced mutant of cyanidium caldarium which lacks the major accessory pigment phycocyanin. 2. Loss of phycocyanin does not impair photosynthesis or the Hill reaction. 3. The action spectrum for the quantum yield indicates an efficiently operating photosynthetic mechanism which is shifted in peak efficiency toward longer wavelengths when compared to the wild-type spectrum. The red drop is also shifted toward the far red in R-II. 4. Although 30 per cent enhancement was obtained in wild-type Cyanidium, no enhancement was observed when phycocyanin was absent. 5. A pigment absorbing at 720 nm has been observed and may possibly represent a chlorophyll-phycocyanin complex. |
