Document Detail


On the advantages of using green light to study fluorescence yield changes in leaves.
MedLine Citation:
PMID:  17123461     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In photosynthetic chains, the kinetics of fluorescence yield depends on the photochemical rates at the level of both Photosystem I and II and thus on the absorption cross section of the photosynthetic units as well as on the coupling between light harvesting complexes and photosynthetic traps. A new set-up is described which, at variance with the commonly used set-ups, uses of a weakly absorbed light source (light-emitting diodes with maximum output at 520 nm) to excite the photosynthetic electron chain and probe the resulting fluorescence yield changes and their time course. This approach optimizes the homogeneity of the exciting light throughout the leaf and we show that this homogeneity narrows the distribution of the photochemical rates. Although the exciting light is weakly absorbed, the possibility to tune the intensity of the light emitting diodes allows one to reach photochemical rates ranging from 10(4) s(-1) to 0.25 s(-1) rendering experimentally accessible different functional regimes. The variations of the fluorescence yield induced by the photosynthetic activity are qualitatively and quantitatively discussed. When illuminating dark-adapted leaves by a weak light, the kinetics of fluorescence changes displays a pronounced plateau which precedes the fluorescence increase reflecting the full reduction of the plastoquinone pool. We ascribe this plateau to the time delay needed to reduce the photosystem I electron acceptors.
Authors:
Fabrice Rappaport; Daniel Béal; Anne Joliot; Pierre Joliot
Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2006-10-27
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1767     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  2007 Jan 
Date Detail:
Created Date:  2007-01-22     Completed Date:  2007-03-01     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  56-65     Citation Subset:  IM    
Affiliation:
Institut de Biologie Physico-Chimique, UMR 7141 CNRS/Paris 6, Paris, France. Fabrice.Rappaport@ibpc.fr <Fabrice.Rappaport@ibpc.fr>
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MeSH Terms
Descriptor/Qualifier:
Color*
Fluorescence*
Kinetics
Light*
Photochemistry / instrumentation*,  methods*
Photosynthesis / physiology*
Photosystem I Protein Complex / metabolism*
Plant Leaves / metabolism,  physiology*
Plastoquinone / metabolism
Chemical
Reg. No./Substance:
0/Photosystem I Protein Complex; 4299-57-4/Plastoquinone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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