title: Salts and chloroplast fluorescence.
abstract: Chlrorplast fluorescence was exicted by a weak measuring beam. A time-separated actinic light was used to modify the redox states of Q which in turn induced a change in the fluorescence yield. In salt-depleted chloroplasts, fluorescence saturated at a low actinic light intensity. CaCl2 increased the "variable" fluorescence as well as the rate of ferricyanide-Hill reaction. With Tris-washed chloroplasts, Photosystem II donor couple, phenylenediamine and ascorbate, did not increase the fluorescnece to a large extent without the presence of CaCl2. It is suggested that salt-depletion inactivates the Photosystem II reaction center of chloroplasts.
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D002523:Edible Grain; D005292:Ferricyanides; D008027:Light; D010084:Oxidation-Reduction; D010655:Phenylenediamines / Q000494:pharmacology; D010944:Plants; D013050:Spectrometry, Fluorescence; D014451:Ubiquinone / Q000378:metabolism
chemical_list: D002413:Cations, Divalent; D005292:Ferricyanides; D010655:Phenylenediamines; D014451:Ubiquinone; D001205:Ascorbic Acid; D002118:Calcium