|Title||The relationship between non-photochemical quenching of chlorophyll fluorescence and the rate of photosystem 2 photochemistry in leaves|
|Author(s)||Genty, Bernard; Harbinson, Jeremy; Briantais, Jean Marie; Baker, Neil R.|
|Source||Photosynthesis Research 25 (1990)3. - ISSN 0166-8595 - p. 249 - 257.|
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Chlorophyll fluorescence - flash-induced kinetics - fluorescence quenching - non-photochemical quenching - photochemistry - photosystem 2|
It has been suggested previously that non-photochemical quenching of chlorophyll fluorescence is associated with a decrease in the rate of photosystem 2 (PS 2) photochemistry. In this study analyses of fluorescence yield changes, induced by flashes in leaves exhibiting different amounts of non-photochemical quenching of fluorescence, are made to determine the effect of non-photochemical excitation energy quenching processes on the rate of PS 2 photochemistry. It is demonstrated that both the high-energy state and the more slowly relaxing components of non-photochemical quenching reduce the rate of PS 2 photochemistry. Flash dosage response curves for fluorescence yield show that non-photochemical quenching processes effectively decrease the relative effective absorption cross-section for PS 2 photochemistry. It is suggested that non-photochemical quenching processes exert an effect on the rate of PS 2 photochemistry by increasing the dissipation of excitation energy by non-radiative processes in the pigment matrices of PS 2, which consequently results in a decrease in the efficiency of delivery of excitation energy for PS 2 photochemistry.