Abstract
When etiolated leaves of dark-grown angiosperms are exposed to light, light-dependent chlorophyll (Chl) synthesis is immediately initiated and the photosynthetic apparatuses are assembled within a few hours. Little is known about the assembly process of synthesized Chl into the photosynthetic reaction-center and antenna apoproteins so far. Here, we studied the time-resolved fluorescence from greening leaves of dark-grown Zea mays by using the streak-camera set-up. By using this instrument, the fluorescence from a sample can be obtained as a time-wavelength 2-D image. The leaves of dark-grown Zea mays 1 hour after the initiation of greening showed the time-wavelength 2-D fluorescence image showing distinct pattern from those of the isolated photosystem I and II. This result suggested that the intermediate state of the photosytem assembly is accumulated 1 hour after the initiation of the light illumination. The time-resolved fluorescence of the intermediate state suggested the excitation-energy transfer process with a time constant of ca. 800 ps, suggesting an ordered arrangement of Chl molecules.
