Spectroscopic analysis of chlorophyll photobleaching in spinach thylakoids, grana and light-harvesting chlorophyll a/b protein complex

Abstract

The absorption spectra of the chlorophyll photobleaching in the wavelength range 600–750 nm of thylakoids, the BBY grana preparation and purified light-harvesting chlorophyll a/b protein complex (LHCP) are presented. These spectra are described as a linear combination of gaussian components over the wavelength range 635–750 nm and the photobleaching of each component is evaluated. We find that all the spectral species of chlorophyll examined are bleached and, for thylakoids and BBY grana preparations, that the bleaching is greatest for those spectral components that peak at longer wavelengths. On the other hand, photobleaching of the LHCPII spectral components is more homogeneous.