Molecular Plant Biology, Department of Biochemistry and Food Chemistry, University of Turku, 20014 Turku, Finland.
J Photochem Photobiol B. 2011 Jul-Aug;104(1-2):292-300. doi: 10.1016/j.jphotobiol.2011.03.013. Epub 2011 Mar 29.
The Q band of photosynthetic thermoluminescence, measured in the presence of a herbicide that blocks electron transfer from PSII, is associated with recombination of the S(2)Q(A)(-) charge pair. The same charge recombination reaction can be monitored with chlorophyll fluorescence. It has been shown that the recombination occurs via three competing routes of which one produces luminescence. In the present study, we measured the thermoluminescence Q band and the decay of chlorophyll fluorescence yield after a single turnover flash at different temperatures from spinach thylakoids. The data were analyzed using the commonly used Arrhenius theory, the Eyring rate theory and the Marcus theory of electron transfer. The fitting error was minimized for both thermoluminescence and fluorescence by adjusting the global, phenomenological constants obtained when the reaction rate theories were applied to the multi-step recombination reaction. For chlorophyll fluorescence, all three theories give decent fits. The peak position of the thermoluminescence Q band is correct by all theories but the form of the Q band is somewhat different in curves predicted by the three theories. The Eyring and Marcus theories give good fits for the decreasing part of the thermoluminescence curve and Marcus theory gives the closest fit for the rising part.
光合光致发光的 Q 带，在存在一种阻断从 PSII 到电子传递的除草剂的情况下进行测量，与 S(2)Q(A)(-)电荷对的复合有关。同样的电荷复合反应可以用叶绿素荧光来监测。已经表明，该复合通过三种竞争途径发生，其中一种产生发光。在本研究中，我们从菠菜类囊体中测量了单个翻转闪光后在不同温度下的光致发光 Q 带和叶绿素荧光产额衰减。使用常用的 Arrhenius 理论、Eyring 速率理论和电子转移的 Marcus 理论对数据进行了分析。通过调整应用于多步复合反应的反应速率理论获得的全局、唯象常数，使光致发光和荧光的拟合误差最小化。对于叶绿素荧光，三种理论都给出了很好的拟合。光致发光 Q 带的峰位置在所有理论中都是正确的，但在三种理论预测的曲线中，Q 带的形状有些不同。Eyring 和 Marcus 理论对于光致发光曲线的下降部分给出了很好的拟合，而 Marcus 理论对于上升部分给出了最接近的拟合。
