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'Chlorophyll Fluorescence' in keywords Facet   Publication Year 1993  [X]
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1Author    WieslawI. Gruszecki, ZbigniewK. RupaRequires cookie*
 Title    Changes of Excitation Spectra of in vivo Chlorophyll Fluorescence during Induction of Photosynthesis  
 Abstract    Excitation spectra of chlorophyll fluorescence from intact rye leaves were registered at dif­ ferent steps of the induction of photosynthesis after dark adaptation. Analysis of these spectra indicates that at least two processes related to spectroscopic features are responsible for a flu­ orescence quenching. The first one, active during the first 100 s of illumination, was interpret­ ed to consists in an overall decrease of the fluorescence quantum yield of antenna pigments and chlorophylls, in particular close to the reaction centers. The second type of a fluorescence decrease (between 100 s and 300 s o f illumination) was found to be in large extent related to decrease of the rate of an excitation energy transfer between accessory xanthophyll pigments and chlorophylls emitting fluorescence. This latter molecular mechanism is discussed as being related to violaxanthin availability to de-epoxidation in the xanthophyll cycle. 
  Reference    Z. Naturforsch. 48c, 46—51 (1993); received September 21/December 31 1992 
  Published    1993 
  Keywords    Chlorophyll Fluorescence, Photosynthesis, Violaxanthin, Xanthophyll Cycle 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0046.pdf 
 Identifier    ZNC-1993-48c-0046 
 Volume    48 
2Author    J. SymRequires cookie*
 Title    The Role of D 1* in Light-Induced D 1 Protein Turnover in Leaves  
 Abstract    ea, H arald R . B olh à r-N ord en kam pfb, and C hrista C ritch ley3 Light-induced degradation o f the D 1 protein of photosystem II (PS II) was determined by radioactive pulse-chase labelling experiments in intact leaves o f Schefflera polybotrya. PS II photochemical efficiency was monitored by measuring chlorophyll fluorescence. A significant and consistent decline in the F J F m ratio was taken to indicate photoinhibition. The formation and degradation o f a modified form o f the D 1 protein, D 1*, was different under photoinhibi-tory or non-photoinhibitory light conditions. At photoinhibitory irradiance greater amounts o f D 1 * were formed relative to D 1, and the degradation of D 1* was slower when compared with non-photoinhibitory irradiance. The formation and degradation o f D 1* were therefore shown to be at least partly light intensity dependent. Higher light intensities appeared to slow D 1* degradation, which suggests a modification in PS II turnover properties. 
  Reference    Z. Naturforsch. 48c, 246 (1993); received December 12 1992 
  Published    1993 
  Keywords    Photosynthesis, Photosystem II, Photoinhibition, D 1 Degradation, Chlorophyll Fluorescence 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0246.pdf 
 Identifier    ZNC-1993-48c-0246 
 Volume    48