BASIC RESEARCH IN PHOTOSYNTHESIS.
Final rept., 1 Oct 60-31 Dec 65,
RIAS INC BALTIMORE MD
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Instrumentation and methodology were developed in the areas of mass spectrometry, sensitive spectroscopy, polarography oxygen exchange, and techniques for irradiating photosynthetic materials with highintensity monochromatic light. Oxygen uptake could be decreased or enhanced during photosynthesis, depending on wavelength of illumination. Photosystem I was sensitized predominantly by long-wave illumination, with suppression of respiratory uptake. Photosystem II, with inducement of increased oxygen uptake key short-wave illumination, was not explained fully. A long-wave chlorophyll component P700 was detected in the chloroplast which occurs in the low concentration of 1 per 100 total chlorophylls. In the primary event of photosystem I, P700, upon excitation must lose an electron to an associated reaction partner. In complete photosynthesis, the P700 is re-reduced by photosystem II. In a study with a mutant of Scenedesmus, the reducing power generated in photosystem II, simultaneaus with oxygen, was not lower than 0.18 volts.