Nonphotochemical quenching of chlorophyll fluorescence in Chlamydomonas reinhardtii.
Unlike plants, Chlamydomonas reinhardtii shows a restricted ability to develop nonphotochemical quenching upon illumination. Most of this limited quenching is due to state transitions instead of DeltapH-driven high-energy state quenching, qE. The latter could only be observed when the ability of the cells to perform photosynthesis was impaired, either by lowering temperature to approximately 0 degrees C or in mutants lacking RubisCO activity. Two main features were identified that account for the low level of qE in Chlamydomonas. On one hand, the electrochemical proton gradient generated upon illumination is apparently not sufficient to promote fluorescence quenching. On the other hand, the capacity to transduce the presence of a DeltapH into a quenching response is also intrinsically decreased in this alga, when compared to plants. The possible mechanism leading to these differences is discussed.
Finazzi
Giovanni
G
Unité Mixte de Recherche 7141 CNRS, Université Paris 6, Institut de Biologie Physico-Chimique, 75005 Paris, France. giovanni.finazzi@ibpc.fr
Johnson
Giles N
GN
Dall'Osto
Luca
L
Zito
Francesca
F
Bonente
Giulia
G
Bassi
Roberto
R
Wollman
Francis-André
FA
D000818:Animals; D017360:Arabidopsis / Q000737:chemistry / Q000528:radiation effects; D016825:Chlamydomonas reinhardtii / Q000737:chemistry* / Q000254:growth & development / Q000528:radiation effects; D002734:Chlorophyll / Q000737:chemistry* / Q000528:radiation effects; D005453:Fluorescence; D008027:Light; D010777:Photochemistry; D013696:Temperature; D013997:Time Factors
D002734:Chlorophyll