Horton P, Baker N R
Biochim Biophys Acta. 1980 Oct 3;592(3):559-64. doi: 10.1016/0005-2728(80)90100-0.
Fluorescence induction at -196 degrees C has been monitored in chloroplasts rapidly frozen after poising at different redox potentials at room temperature. It was found that, as at room temperature, the initial level of fluorescence observed upon shutter opening (Fo), relative to the final level observed after 10 seconds of illumination (Fm) increased as the redox potential of the chloroplasts was lowered. Redox titration and revealed the presence of two quenching components with Em, 7.8 at -70 mV and -275 mV accounting for approx. 75% and 25% of the variable fluorescence (Fv). Parallel observation of fluorescence yield at room temperature similarly gave two components, with Em, 7.8 at -95 mV and -290 mV, also accounting for appox. 75% and 25%. Simultaneous measurement of fluorescence emission at -196 degrees C at 695 nm and 735 nm indicated that both emissions are quenched by the same redox components.
在室温下将叶绿体置于不同氧化还原电位后快速冷冻，监测了-196℃下的荧光诱导情况。结果发现，与室温下一样，随着叶绿体氧化还原电位的降低，快门打开时观察到的初始荧光水平（Fo）相对于光照10秒后观察到的最终水平（Fm）会升高。氧化还原滴定显示存在两种猝灭成分，其Em分别为-70 mV时的7.8和-275 mV时的7.8，分别占可变荧光（Fv）的约75%和25%。在室温下对荧光产率进行的平行观察同样得到两种成分，其Em分别为-95 mV时的7.8和-290 mV时的7.8，也分别约占75%和25%。在-196℃下同时测量695 nm和735 nm处的荧光发射表明，两种发射均被相同的氧化还原成分猝灭。
