The Association between Galactolipids and Chlorophyll-Protein Complexes

Abstract

Photobleaching of chloroplasts is normally accompanied by extensive lipid peroxidation (1). in an accompanying communication, we have shown that inhibition of PS II leads to increased rates of photobleaching of a long-wavelength chlorophyll a component associated with PS I. The light-harvesting units of PSI are known to be preferentially located in the non-appressed membranes of the stroma lamellae while those of PSII are located mainly in the appressed membranes of the grana stacks (2). This lateral separation of the two photosystem s means that photo-oxidative damage preferentially associated with one of the two photosystem s might be expected to be reflected in localised damage within the chloropast membrane system. with this in mind, we have examined the loss of the two main classes of galactolipid in order to see if there is any evidence to support the suggestion that MGDG is associated with the packaging of photosynthetic light-harvesting units within the thylakoid membrane (3).