Studies of Chloroplast Development in Euglena. V. Pigment Biosynthesis, Photosynthetic Oxygen Evolution and Carbon Dioxide Fixation during Chloroplast Development

Abstract
Measurements were obtained of the photo-synthetic capacity of dark-grown cells of Euglena gracilis var. bacillaris Pringsheim exposed to optimum light intensities (100 ft-c). These include values for oxygen evolution, carbon dioxide fixation, and pigment synthesis as a function of time in the light in dividing and nondividing cells. There is an initial 6-8-hour lag in the rates of increase of all photosynthetic parameters when dark-grown cells are placed in the light. This is followed by essentially linear kinetics for all parameters until about 80 hours, when these values are equivalent to those found for light-grown cells. The kinetics of appearance for all photosynthetic parameters are the same for dividing and nondividing cells. The onset of linear kinetics for all photosynthetic measurements is correlated with the linear formation of the chloroplast lamellae and the rates of all parameters are the same as the rate of lamella formation. Various mutants limited at different stages in chloroplast development were also tested for their capacity to photosynthesize, and a correlation was found between photosynthetic ability and the extent of chloroplast development.