Document Detail


Quantification of non-QB-reducing centers in leaves using a far-red pre-illumination.
MedLine Citation:
PMID:  16049767     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
An alternative approach to quantification of the contribution of non-QB-reducing centers to Chl a fluorescence induction curve is proposed. The experimental protocol consists of a far-red pre-illumination followed by a strong red pulse to determine the fluorescence rise kinetics. The far-red pre-illumination induces an increase in the initial fluorescence level (F(25 micros)) that saturates at low light intensities indicating that no light intensity-dependent accumulation of QA - occurs. Far-red light-dose response curves for the F(25 micros)-increase give no indication of superimposed period-4 oscillations. F(25 micros)-dark-adaptation kinetics following a far-red pre-pulse, reveal two components: a faster one with a half-time of a few seconds and a slower component with a half-time of around 100 s. The faster phase is due to the non-QB-reducing centers that re-open by recombination between QA - and the S-states on the donor side. The slower phase is due to the recombination between QB - and the donor side in active PS II reaction centers. The pre-illumination-induced increase of the F(25 micros)-level represents about 4-5% of the variable fluorescence for pea leaves ( approximately 2.5% equilibrium effect and 1.8-3.0% non-QB-reducing centers). For the other plant species tested these values were very similar. The implications of these values will be discussed.
Authors:
Gert Schansker; Reto J Strasser
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Photosynthesis research     Volume:  84     ISSN:  0166-8595     ISO Abbreviation:  Photosyn. Res.     Publication Date:  2005 Jun 
Date Detail:
Created Date:  2005-07-28     Completed Date:  2006-01-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954728     Medline TA:  Photosynth Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  145-51     Citation Subset:  IM    
Affiliation:
Bioenergetics Laboratory, University of Geneva, Chemin des Embrouchis 10, 1254, Jussy, Geneva, Switzerland. Gert.Schansker@bioen.unige.ch
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MeSH Terms
Descriptor/Qualifier:
Chlorophyll / chemistry,  metabolism
Color
Dose-Response Relationship, Radiation
Ficus / metabolism,  radiation effects
Fluorescence
Light*
Peas / chemistry,  metabolism,  radiation effects
Photochemistry
Photosystem II Protein Complex / chemistry,  metabolism
Plant Leaves / metabolism*,  radiation effects*
Species Specificity
Chemical
Reg. No./Substance:
0/Photosystem II Protein Complex; 1406-65-1/Chlorophyll; 479-61-8/chlorophyll a

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


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