Document Detail


The fluorescence induction kinetics as a non-destructive tool for investigating spruce treated with ozone.
MedLine Citation:
PMID:  2305029     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The scattering coefficient of yellow spruce needles exceeds that of green needles by a factor of 2, whereas the fluorescence efficiency is approximately equal for both needle colours. As shown by the angular distribution the fluorescence light is diffusely emitted. However, the scattered light consists of a diffuse and a reflecting portion below 20 degrees with a ratio of the intensities of 1 : 2 at perpendicular observation (0 degrees). Control measurements show that in the rejection region the effective transmission of cut-off-filters commonly used to separate fluorescence light and excitation light exceeds the value calculated from the filter specifications by a factor of 100. Therefore, the portion of the scattered light in the measuring signal must be controlled if the fluorescence induction kinetics is measured from specimen of different colour. A device for the determination of the fluorescence induction kinetics is described which employs a He--Ne laser, a mechanically working shutter with an opening time of 4 ms for the excitation, and a computer for data storage and device control. Two filters select the fluorescence components at 685 nm and 730 nm and they reduce the portion of the scattered light in the measuring signal to 0.18% and 0.55%, respectively. In order to consider the temporal development of the fluorescence kinetics the sampling rate is reduced from 2 kHz to 1 Hz. From the data stored in the computer maximum value Fp, and steady-state-value Fs are determined for both fluorescence components. Measurements on 4-year-old spruce exposed to ozone-concentrations of 0, 300 ppb, 600 ppb, and 1000 ppb were repeated every week. With increasing concentration and duration of treatment Rfd = (Fp-Fs)/Fs was decreased for both fluorescence components. With the highest ozone concentration a reduction of Rfd of 23% and 24%, respectively, was obtained for the two fluorescence components after three weeks.
Authors:
B Ruth
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Radiation and environmental biophysics     Volume:  29     ISSN:  0301-634X     ISO Abbreviation:  Radiat Environ Biophys     Publication Date:  1990  
Date Detail:
Created Date:  1990-03-23     Completed Date:  1990-03-23     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0415677     Medline TA:  Radiat Environ Biophys     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  57-73     Citation Subset:  IM    
Affiliation:
MEDIS-Institut, Gesellschaft für Strahlen- und Umweltforschung mbH München, Neuherberg, Federal Republic of Germany.
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MeSH Terms
Descriptor/Qualifier:
Chemistry, Physical
Fluorescence
Kinetics
Light
Ozone / pharmacology*
Physicochemical Phenomena
Plants / metabolism
Scattering, Radiation
Spectrum Analysis
Time Factors
Trees*
Chemical
Reg. No./Substance:
10028-15-6/Ozone

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


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