Spatial location of photosystem pigment–protein complexes in thylakoid membranes of chloroplasts of Pisum sativum studied by chlorophyll fluorescence

Ultrastructure of plant chloroplasts was studied by a single-molecule spectroscopy setup at a temperature of 77 K exploring spatial location of photosystems. Two chloroplast thylakoid membrane regions were visualized by fluorescence microscopy and detected at different wavelengths. The size of these regions and the spatial resolution of the microscope allowed us to measure their chlorophyll fluorescence emission spectra of these membrane domains. While the grana regions are characterized by a predominant presence of Photosystem II pigment–protein complexes emitting at 685 nm, Photosystem I complexes are localized in stroma regions and emit at 730 nm.