fluorescence kinetics

Gz =?UNKNOWN?Q?G=9Fnther?= goegue at water.gm.ufz.de
Thu May 23 12:07:58 EST 1996

I have got two questions with regard to the measurements of fluorescence

(i) measure the in vivo induction kinetics of algea: a) the excitation
light is focused; the advantage of this procedure is a high intensity
at a small volume of suspension or b) the excitation light is scattered
which results in comparative homogeneous ambient lighting.
Using the same excitation intensity  the irradiation experiments
revealed for example two different Kautsky-kinetics for a single
suspension with the same adaption (and unchanged detector).
Which method is to be recommended? Which method will be more correct and
for what reason?

(ii) measurements of spontaneous fluorescence normalized to
chl-a-concentration at natural waters show often a fluorescence rise
characteristic during sunset and sunrise (Gorbunov, M.Y. & Chekalyuk,
A.M. report on these phenomenon in various papers as well). Is there a
new approach of explanation?

The third and last question concerns pheophytin.
(iii) Can you give me some information about the occurrence and origin
of this pigment outside of RC II or  can you tell me where I can find

Many thanks for helping me
goetz guenther

* Goetz Guenther
* UFZ Research Centre
* Department Water Research
* Heydeckstrasse 9a
* 39104 Magdeburg
* phone: +49 391 5681534
* fax: +49 391 5681544

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