Fluorescence Properties of Wild-Type Chlamydomonas reinhardi and Three Mutant Strains Having Impaired Photosynthesis

Abstract

The wild-type strain of Chlamydomonas reinhardi and 3 mutant strains ac-21, ac-141, and ac-115 have been compared for their fluorescence (and luminescence) properties. The different fluorescence levels, the rapid and slow photochemical responses affecting fluorescence, and the intensity of luminescence have been studied under various conditions: air, nitrogen, 3(p-chlorophenyl)-1,1-dimethylurea. The strain ac-21 exhibits fluorescence properties only quantitatively different from those of the wild-type strain, and it is believed to be affected in some component of the electron transport chain between the 2 light reactions. Both ac-141 and ac-115 have an abnormally high initial fluorescence level; ac-115 does not show the normal photochemical response associated with System II and has a very low luminescence. Mutant strains ac-141 and ac-115 both seem to be modified in the System II photochemical center. These conclusions are compared with a previous analysis based on absorbance changes of cytochrome 559.