Abstract
We describe a methodology to visualize three dimensional
distributions of photosystems in the thylakoid membrane in
chloroplasts under nearly in-vivo conditions. Chlorophyll
fluorescence spectra from the chloroplasts in leaves of
Zea mays were analyzed at room temperature by a newly
developed spectroimaging microscope employing a two-photon
excitation at 800 nm. We have first determined two
wavelength regions, by which one can exclusively probe the
fluorescence from photosystem 1 and 2, each of which
includes associated light-harvesting complexes. The map
of photosystem 2 fluorescence often show fine structures
in which fluorescence intensity exhibit local peaks and
valleys with a characteristic length as short as 0.3
μm. The local peaks plausibly correspond to the granal
stacked part of the membrane. The distribution of PS1
fluorescence was certainly different from that that of
PSII. Implications of these results for the detailed
picture of thylakoid membrane in the chloroplasts will be
discussed.
