deltapH-dependent photosystem II fluorescence quenching induced by saturating, multiturnover pulses in red algae

• Published in: Plant physiology (Bethesda) Vol. 118; no. 1; pp. 103 - 113
• Main Authors: Delphin, E. (Centre National de la Recherche Scientifique, Paris, France.), Duval, J.C, Etienne, A.L, Kirilovsky, D
• Format: Journal Article
• Language: English
• Published: United States 01.09.1998
• Subjects: 2,5-DIBROMO-3-METHYL-6-ISOPROPYL-P-BENZOQUINONE; 3-(3,4-DICHLOROPHENYL)-1,1-DIMETHYLUREA; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; BENZOQUINONE; CHLOROPHYLLE; CHLOROPHYLLS; CHOIX DE LA DATE; CLOROFILAS; DARKNESS; DERIVATIVES; ELECCION DE LA EPOCA; ELECTRON TRANSFER; ENZYME INHIBITORS; ENZYMIC ACTIVITY; FLUORESCENCE; FLUORESCENCIA; FOTOSISTEMAS; GREEN LIGHT; HIDROLASAS; HYDROLASE; HYDROLASES; INHIBIDORES DE ENZIMAS; INHIBITEUR D'ENZYME; LIGHT; LIGHT INTENSITY; LUMIERE; LUZ; N,N'-DICYCLOHEXYL CARBODIIMIDE; OBSCURIDAD; OBSCURITE; OXIDOREDUCTIONS; OXIRREDUCION; OXYDOREDUCTION; PHOTOSYSTEME; PHOTOSYSTEMS; PYROPHOSPHATASES; QUINONAS; QUINONE; QUINONES; RHODOPHYCEAE; TIMING; UREA; UREE; WHITE LIGHT
• ISSN: 0032-0889; 1532-2548

We have previously shown that in the red alga Rhodella violacea, exposure to continuous low intensities of light 2 (green light) or near-saturating intensities of white light induces a deltapH-dependent PSII fluorescence quenching. In this article we further characterize this fluorescence quenching by using white, saturating, multiturnover pulses. Even though the pulses are necessary to induce the deltapH and the quenching, the development of the latter occurred in darkness and required several tens of seconds. In darkness or in the light in the presence of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, the dissipation of the quenching was very slow (more than 15 min) due to a low consumption of the deltapH, which corresponds to an inactive ATP synthase. In contrast, under far-red illumination or in the presence of 3-(3,4-dichlorophenyl)-1,1'dimethylurea (only in light), the fluorescence quenching relaxed in a few seconds. The presence of N,N'-dicyclohexyl carbodiimide hindered this relaxation. We propose that the quenching relaxation is related to the consumption of deltapH by ATP synthase, which remains active under conditions favoring pseudolinear and cyclic electron transfer