Velthuys B R, Amesz J
Biochim Biophys Acta. 1975 Jan 31;376(1):162-8. doi: 10.1016/0005-2728(75)90214-5.
Delayed fluorescence (luminescence) from spinach chloroplasts, induced by short saturating flashes, was studied in the temperature region between 0 and minus 40 degrees C. At these temperatures, in contrast to what is observed at room temperature, luminescence at 40 ms after a flash was strongly dependent, with period four, on the number of preilluminating flashes (given at room temperature, before cooling). At minus 35 degrees C luminescence of chloroplasts preilluminated with two flashes (the optimal preillumination) was about 15 times larger than that of dark-adapted chloroplasts. The intensity of luminescence obtained with preilluminated chloroplasts increased steeply below minus 10 degrees C, presumably partly due to accumulation of reduced acceptor (Q minus), and reached a maximum at minus 35 degrees C. In the presence of 50 mM NH4Cl; at temperatures below minus 20 degrees C luminescence at 40 ms was decreased by NH4C1. At room temperature a strongly enhanced 40-ms luminescence was observed after the third and following flashes. The results indicate that both the S2 to S3 and the S3 to S4 conversion are affected by NlH4Cl. Inhibitors of Q minus reoxidation, like 3-(3, 4-dichlorophenyl)-1, 1-dimethylurea, did only slightly affect the preillumination dependence of luminescence at sub-zero temperatures if they were added after the preillumination. This indicates that these substances by themselves do not accelerate the deactivation of S2 and S3.
研究了在0至零下40摄氏度温度范围内，由短饱和闪光诱导的菠菜叶绿体延迟荧光（发光）。在这些温度下，与室温下观察到的情况相反，闪光后40毫秒时的发光强烈地以四周期依赖于预照明闪光的次数（在冷却前于室温下给出）。在零下35摄氏度时，用两次闪光预照明的叶绿体（最佳预照明）的发光比暗适应的叶绿体大约大15倍。预照明叶绿体获得的发光强度在零下10摄氏度以下急剧增加，大概部分是由于还原受体（Q-）的积累，并在零下35摄氏度时达到最大值。在存在50 mM NH4Cl的情况下，在零下20摄氏度以下的温度下，40毫秒时的发光被NH4Cl降低。在室温下，第三次及后续闪光后观察到40毫秒时的发光强烈增强。结果表明，S2到S3以及S3到S4的转换都受到NH4Cl的影响。Q-再氧化的抑制剂，如3-(3,4-二氯苯基)-1,1-二甲基脲，如果在预照明后添加，在零下温度下对发光的预照明依赖性只有轻微影响。这表明这些物质本身不会加速S2和S3的失活。
