Biology Department, Carleton University, K1S 5B6, Ottawa, Ontario, Canada.
Photosynth Res. 1990 Jun;24(3):209-20. doi: 10.1007/BF00032308.
A study was made of the fluorescence induction curves from gently-broken spinach chloroplasts inhibited with DCMU. It was found that there were four kinetically different phases associated with such curves of which only the fastest did not appear to follow exponential kinetics. A comparison of the effects of various concentrations of DCMU on the rate of oxygen evolution and on the fluorescence induction curve did not support the hypothesis that any of the kinetic phases was simply an artefact caused by incomplete inhibition of electron transport. It was also found that 5 min of dark incubation did not maximally oxidize the electron acceptors to photosystem 2 since some acceptors were only oxidized following far-red illumination, suggesting a heterogeneity among these acceptors with respect to their re-oxidation properties. Investigation of the effect of the Q400 oxidation state on the fluorescence induction curve revealed that it only influenced the slowest kinetic phase and that Q400 did not seem to be associated with the other phases.
研究了用 DCMU 抑制的菠菜叶绿体轻微破碎后产生的荧光诱导曲线。结果发现，与这些曲线相关的有四个动力学上不同的阶段，其中只有最快的阶段似乎不符合指数动力学。比较不同浓度的 DCMU 对氧气释放速率和荧光诱导曲线的影响，并不支持任何动力学阶段仅仅是由于电子传递不完全抑制而产生的假象的假说。还发现，5 分钟的暗处理并不能使电子受体最大程度地氧化到光系统 2，因为只有在远红光照射下，一些受体才被氧化，这表明这些受体在其再氧化特性方面存在异质性。对 Q400 氧化态对荧光诱导曲线的影响的研究表明，它只影响最慢的动力学阶段，并且 Q400 似乎与其他阶段无关。
