Düsseldorf 2007 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 68: Laserspektroskopie I
Q 68.1: Talk
Friday, March 23, 2007, 10:30–10:45, 5K
time and wavelength resolved fluorescence spectroscopy of photoinhibited photosynthetic organisms using a novel multi channel photomultiplier system — •Karin Wache1, Franz-Josef Schmitt1, Justus Fuesers1, Christoph Theiss1, Stefan Andree1, Hans Joachim Eichler1, and Hann-Jörg Eckert2 — 1Optisches Institut - P 1-1, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin — 2Max-Volmer-Laboratorium, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin
A novel multi channel photomultiplier PML-16C (Becker & Hickl, Berlin) is used for time and wavelength resolved fluorescence measurements of photosynthetic organisms. The photomultiplier detects fluorescence photons simultaneously in the time domain and in 16 wavelength channels. As a result of high count rates up to 10^6 counts/sec very short measurement times are possible. Therefore this detector can be used for fast monitoring of changes of the fluorescence kinetics appearing after photoinhibition of the photosynthetic organisms with strong white light. Due to the short measurement times it is possible to investigate the dynamics of metabolic changes and repair mechanisms. The cyanobacterium Acaryochloris marina is an unique photosynthetic organism containing mainly Chl d instead of Chl a in the membrane intrinsic light harvesting systems. The investigation of photoinhibited cells of A. marina showed changes of the Chl d-fluorescence at 725 nm due to quenching after photoinhibition similar to what is observed in the Chl a fluorescence in typical Cyanobacteria or higher plants.