Abteilung Biophysik, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastraße 11, D-49069, Osnabrück, Germany.
Photosynth Res. 1996 May;48(1-2):255-62. doi: 10.1007/BF00041016.
Excitation of photosynthetic systems with short intense flashes is known to lead to exciton-exciton annihilation processes. Here we quantify the effect of competition between annihilation and trapping for Photosystem II, Photosystem I (thylakoids from peas and membranes from the cyanobacterium Synechocystis sp.), as well as for the purple bacterium Rhodospirillum rubrum. In none of the cases it was possible to reach complete product saturation (i.e. closure of reaction centers) even with an excitation energy exceeding 10 hits per photosynthetic unit. The parameter α introduced by Deprez et al. ((1990) Biochim. Biophys. Acta 1015: 295-303) describing the competition between exciton-exciton annihilation and trapping was calculated to range between ≈4.5 (PS II) and ≈6 (Rs. rubrum). The rate constants for bimolecular exciton-exciton annihilation ranged between (42 ps)(-1) and (2.5 ps)(-1) for PS II and PS I-membranes of Synechocystis, respectively. The data are interpreted in terms of hopping times (i.e. mean residence time of the excited state on a chromophore) according to random walk in isoenergetic antenna.
用短而强的闪光激发光合作用系统已知会导致激子激子湮灭过程。在这里，我们定量地研究了 PSII、PSI（豌豆类囊体和蓝藻 Synechocystis sp. 的膜）以及紫色细菌 Rhodospirillum rubrum 之间湮灭和捕获竞争的影响。在任何情况下，即使激发能量超过每个光合作用单元 10 次，也不可能达到完全的产物饱和（即反应中心关闭）。Deprez 等人引入的参数α（1990 年，Biochim. Biophys. Acta 1015：295-303）描述了激子激子湮灭和捕获之间的竞争，其范围在≈4.5（PSII）和≈6（Rs. rubrum）之间。对于 PSII 和 Synechocystis 的 PSI-膜，双分子激子激子湮灭的速率常数分别为（42 ps）（-1）和（2.5 ps）（-1）。根据等能量天线中的随机游动，数据用跳跃时间（即发色团上激发态的平均停留时间）进行解释。
