Počet záznamů: 1  

On the polyphasic quenching kinetics of chlorophyll a fluorescence in algae after light pulses of variable length

  1. 1. 0422526 - MBU-M 2014 RIV NL eng J - Článek v odborném periodiku
    Vredenberg, W. - Prášil, Ondřej
    On the polyphasic quenching kinetics of chlorophyll a fluorescence in algae after light pulses of variable length.
    Photosynthesis Research. Roč. 117, 1-3 (2013), s. 321-337 ISSN 0166-8595
    Grant CEP: GA MŠk(CZ) ED2.1.00/03.0110
    Institucionální podpora: RVO:61388971
    Klíčová slova: Chlorophyll a fluorescence * Photosystem II * Quenching kinetics
    Kód oboru RIV: EE - Mikrobiologie, virologie
    Impakt faktor: 3.185, rok: 2013

    This study reports on kinetics of the fluorescence decay in a suspension of the alga Scenedesmus quadricauda after actinic illumination. These are monitored as the variable fluorescence signal in the dark following light pulses of variable intensity and duration. The decay reflects the restoration of chlorophyll fluorescence quenching of the photosystem II (PSII) antennas and shows a polyphasic pattern which suggests the involvement of different processes. The overall quenching curve after a fluorescence-saturating pulse (SP) of 250-ms duration, commonly used in pulse amplitude modulation applications as the tool for estimating the maximal fluorescence (F (m)), has been termed P-O, in which P and O have the same meaning as used in the OJIP induction curve in the light. Deconvolution of this signal shows at least three distinguishable exponential phases with reciprocal rate constants of the order of 10, 10(2), and 10(3) ms. The size of the long (> 10(3) ms) and moderate (10(2) ms) lasting components relative to the complete quenching signal after an SP increases with the duration of the actinic pulse concomitantly with an increase in the reciprocal rate constants of the fast (10 ms) and moderate quenching phases. Fluorescence responses upon single turnover flashes of 30-mu s duration (STFs) given at discrete times during the P-O quenching were used as tools for identifying the quencher involved in the P-O quenching phase preceding the STF excitation. Results are difficult to interpret in terms of a single-hit two-state trapping mechanism with distinguishable quenching properties of open and closed reaction centers only.
    Trvalý link: http://hdl.handle.net/11104/0228740