Barber J, Searle G F, Tredwell C J
Biochim Biophys Acta. 1978 Feb 9;501(2):174-82. doi: 10.1016/0005-2728(78)90024-5.
The MgCl2-induced chlorophyll fluorescence yield changes in broken chloroplasts, suspended in a cation-free medium, treated with 3,-(3',4'-dichlorophenyl)-1,1-dimethylurea and pre-illuminated, has been investigated on a pico-second time scale. Chloroplasts in the low fluorescing state showed a fluorescence decay law of the form exp --At1/2, where A was found to be 0.052 ps-1/2, and may be attributed to the rate of spillover from Photosystem II to Photosystem I. Addition of 10 mM MgCl2 produced a 50% increase in the steady-state fluorescence quantum yield and caused a marked decrease in the decay rate. The fluorescence deday law was found to be predominantly exponential with a 1/e lifetime of 1.6 ns. These results support the hypothesis that cation-induced changes in the fluorescence yield of chlorophyll are related to the variations in the rate of energy transfer from Photosystem II to Photosystem I, rather than to changes in the partitioning of absorbed quanta between the two systems.
研究了在无阳离子介质中悬浮、用3-(3',4'-二氯苯基)-1,1-二甲基脲处理并预照光的破碎叶绿体中，MgCl₂诱导的叶绿素荧光产率变化，时间尺度为皮秒。处于低荧光状态的叶绿体显示出exp(-At¹/₂)形式的荧光衰减规律，其中A为0.052 ps⁻¹/₂，这可能归因于从光系统II到光系统I的溢出速率。添加10 mM MgCl₂使稳态荧光量子产率增加50%，并导致衰减速率显著降低。发现荧光衰减规律主要呈指数形式，1/e寿命为1.6 ns。这些结果支持以下假设：阳离子诱导的叶绿素荧光产率变化与从光系统II到光系统I的能量转移速率变化有关，而不是与两个系统之间吸收量子的分配变化有关。
