Spectroscopic properties and related functions of the stigma measured in living cells of Euglena gracilis

Abstract
The spectroscopic properties of stigma inside green and dark-grown cells and of isolated stigma globules have been studied by means of a microspectrophotometer built in the Laboratory. On the base of these results and of the analysis of the absorption spectra of a stigma suspension, cell suspension and cell methanolic extracts, it can be inferred that pigments localized in the stigma are free carotenoids which are not closely packed and do not show an ordered arrangement. Furthermore, the efficiency of the stigma as shading device is duscussed.