叶绿体长延时(τ>5s)荧光成分产生机理的实验验证

Experiment Evidence for Origin Mechanism of Long-lifetime(τ>5 s) Delayed Fluorescence of Chloroplast

延迟荧光中各成分产生机理的研究对延迟荧光的应用具有重要指导意义。从电荷复合理论出发,对叶绿体光诱导延迟荧光的产生机制进行了简化的理论模拟,得出了延迟荧光的衰减动力学方程,并推断延迟荧光衰减动力学方程中的常数C为延迟荧光中的更长延时成分。其产生机理是由于PSⅠ中的电子回流到PSⅡ与P680+复合产生激发态的P680*退激发产生,并从实验上成功地证明了延迟荧光的长延时(τ>5 s)成分来源的这种电子回流、复合和退激发过程。

Delayed fluorescence （DF） is the luminescence phenomenon of plant photosynthestic apparatus after stop illuminating, it is also called delayed light emission （DLE） for that it has the same wave with fluorescence and is delayed after fluorescence. DF is not only the internal fluorescence probe for the efficiency of charges separation in the P680, but also the useful implement to distinguish that photosynthesis produced on antenna or on electron transfer chain, hence, it is used widely in study on the photosynthestic capacity of plant and on the stress effects of environment on plant. Research of the mechanism for delayed fluorescence origin plays an important role in the application of DF. Based on the Charge Recombination Theory （ CRT）, the mechanism for delayed fluorescence origin is theoretically analyzed in this paper. The decay kinetic equation of DF can be well fitted by poly-exponent. We postulated that constant ＂C＂ is a symbol for component of delayed fluorescence, whose lifetime is more longer than other component, and it is come form the backward transport electron from PS Ⅰ to PS Ⅱ and the recombination of P680^＋ Fortunately, we successfully and firstly testified that the third component （constant C） with lifetime （τ 〉 5 s） much greater than the time of the registration period （which is presented as a constant）, is corresponds to the backward transport electron from PS Ⅰ and the recombination of P680^＋. The experimental evidence has significance on the study on the mechanism for the delayed fluorescence origin of higher plant chloroplast, it also provides a quantitative analysis standard for the rapid dermination of the photosynthestic rate of plant by using plant light-induced delay fluorescence.