Flash Photolysis of Liposomes Containing Chlorophyll and Zeaxanthin, as a Function of Temperature (2°-34 °C)

Abstract

The transfer of triplet excitation from chlorophyll to zeaxanthin in liposomes is a function of temperature and pigment concentration. At 525 nm both chlorophyll and zeaxanthin triplet states are observed. The result is a biphasic increase in absorption. The rise time of absorption by the chlorophyll triplet is much faster, than by the zeaxanthin triplet. With increasing temperature the contribution of absorption by zeaxanthin (relative to that of chlorophyll) at 525 nm increases, and its rise time gets faster. At high ratios of zeaxanthin to chlorophyll, temperature has less effect on both the rise time and absorption by the zeaxanthin triplet state. The chlorophyll triplet is measured at 780 nm. It decays faster with increasing temperature and or increasing ratio of zeaxanthin to chlorophyll. The results are interpreted in terms of: increasing fluidity of the lipid liposome with temperature, formation of zeaxanthin-chlorophyll complexes at high ratios of zeaxanthin and chlorophyll, presence of different lipid phases in the liposome bilayer. © 1984, Walter de Gruyter. All rights reserved.