Fluorescence Changes During Chlorophyll Formation in Euglena gracilis (and Other Organisms) and an Estimate of Lamellar Area as a Function of Age

SYNOPSIS. In the present study, we show for various photosynthetic organisms in the mature state the diversity which exists in the relative fluorescence intensities of the aggregate and monomer of chlorophyll (at both room temperature and the temperature of liquid nitrogen). For a number of forms, but especially for Euglena gracilis , the spectral transformations which accompany greening are reported. The onset of photosynthetic activity is correlated with a steep (almost step‐like) rise in the ratio of aggregate to monomer fluorescence. From this ratio we calculate the “effective” concentration of chlorophyll and estimate lamellar area as a function of greening.