Markovic D Z, Carpentier R
Centre de recherche en photobiophysique, Université du Québec à Trois-Rivières, Canada.
Biochem Cell Biol. 1995 May-Jun;73(5-6):247-52. doi: 10.1139/o95-030.
Simultaneous measurements of chlorophyll fluorescence and thermal emission using photoacoustic spectroscopy have been done in isolated thylakoid membranes to study the relationship between the photochemical quenching of fluorescence (qPF) and energy storage measured in photoacoustic experiments. It is shown that energy storage can be interpreted as the photochemical quenching of a variable component of thermal dissipation termed qPH. The parameters qPF were similarly sensitive to light intensity as demonstrated by their half-saturation light intensity. However, the nonvariable part of thermal dissipation (Ho) represented a greater proportion of the maximal thermal dissipation yield in comparison with the corresponding non-variable component of fluorescence (Fo) as a result of the thermal energy losses occurring during electron transport. A residual qPH found when qPF was removed indicated the participation of cyclic photosystem I or photosystem II in the measured qPH. The participation of cyclic photosystem I was also suggested by a low constant K, representing the quasi equilibria between (re)oxidized and reduced photosystem II quinone acceptors as determined from the logarithmic plots of the hyperbolic relationship obtained between qPH and light intensity. It is finally concluded that the terminology and mathematical treatments used for fluorescence measurements can be applied to thermal dissipation.
利用光声光谱法同时测量分离类囊体膜中的叶绿素荧光和热发射，以研究荧光的光化学猝灭（qPF）与光声实验中测量的能量存储之间的关系。结果表明，能量存储可解释为热耗散可变组分的光化学猝灭，称为qPH。qPF参数对光强的敏感性类似，这可由其半饱和光强证明。然而，由于电子传递过程中发生的热能损失，热耗散的非可变部分（Ho）与荧光的相应非可变组分（Fo）相比，在最大热耗散产额中占更大比例。去除qPF后发现的残余qPH表明循环光系统I或光系统II参与了测量的qPH。低常数K也表明循环光系统I的参与，该常数代表从qPH与光强之间的双曲线关系的对数图确定的（再）氧化和还原光系统II醌受体之间的准平衡。最后得出结论，用于荧光测量的术语和数学处理可应用于热耗散。
