Control of excitation transfer in photosynthesis. II. Magnesium ion-dependent distribution of excitation energy between two pigment systems in spinach chloroplasts.
Control of excitation transfer in photosynthesis. II. Magnesium ion-dependent distribution of excitation energy between two pigment systems in spinach chloroplasts.
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DOI：
10.1016/0005-2728(69)90045-0
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发表时间：
1969-10
期刊：
影响因子：
--
通讯作者：
Norio Murata
中科院分区：
文献类型：
--
作者：
Norio Murata
1.1. 研究了金属离子对菠菜叶绿体叶绿素荧光产量的影响。在室温和液氮温度下，添加Mg2+提高了色素系统II中684 nm和695 nm处叶绿素发光的产率，降低了色素系统i中735 nm处叶绿素发光的产率，改变了室温下荧光诱导的模式，增加了荧光的可变成分。在弱光强区域研究了Mg2+对两种光反应量子产率的影响。Mg2+加速了与2,6-二氯酚的Hill反应所测得的光反应II的速率，而在2,6-二氯酚和3-（3 ',4 ' -二氯苯基）-1,1-二甲基脲存在时，Mg2+抑制了NADP+还原所测得的光反应I的速率。这些事实表明，Mg2+控制了两种色素系统之间的激发能分布，其控制主要表现在从色素系统II的叶绿素体分子向色素系统I的叶绿素体分子的激发转移速率的变化；即Mg2+抑制了激发能从色素系统II向色素系统I的外溢。
1.1. Effects of metal ions on the yields of chlorophyllafluorescence were investigated in spinach chloroplasts. At room and liquid-nitrogen temperatures, addition of Mg2+increased the yields of two emissions of chlorophylla, having peaks at 684 and 695 nm which were emitted from pigment system II and decreased the yield of another emission of chlorophyllaat about 735 nm which was emitted from pigment system I. Mg2+also changed the pattern of the fluorescence induction at room temperature to increase the variable component of fluorescence.2.2. Effects of Mg2+on the quantum yields of the two photoreactions were investigated in a region of weak light intensities. Mg2+accelerated the rate of photoreaction II measured by the Hill reaction with 2,6-dichlorophenolindophenol and depressed the rate of photoreaction I measured by the NADP+reduction in the presence of reduced 2,6-dichlorophenolindophenol and 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea.3.3. These facts indicate that Mg2+controls the distribution of excitation energy between the two pigment systems and that the control consists mainly in change in rate of excitation transfer from the bulk chlorophyllamolecules in pigment system II to those in pigment system I; namely, Mg2+suppresses the spillover of excitation energy from pigment system II to pigment system I.