ENERGY-STORAGE OF LINEAR AND CYCLIC ELECTRON FLOWS IN PHOTOSYNTHESIS
ENERGY-STORAGE OF LINEAR AND CYCLIC ELECTRON FLOWS IN PHOTOSYNTHESIS
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DOI：
10.1104/pp.100.4.1869
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发表时间：
1992-12-01
期刊：
影响因子：
7.4
通讯作者：
MAUZERALL, DC
中科院分区：
文献类型：
--
作者：
CHA, Y;MAUZERALL, DC
利用脉冲时间分辨光声技术测定了绿色小球藻光合作用的能量储存。在光合作用中的线性电子转移过程中，循环光系统（PS）I，并可能PSII的能量存储确定通过选择的激发波长和闪光的间隔。在695 nm激发下，在1 μ s闪光后，在8 ms获得了0.68 +/-0.04 eV/量子能量的相当大的循环PSI能量存储。该能量在0.35至60 s的闪光间隔下保持相同，并且与3-（3，4-二氯苯基）-1，1-二甲基脲的存在无关。我们暂时将这种能量分配给铁氧还蛋白-NADP-还原酶-铁氧还蛋白和氧化的细胞色素b6/f复合物。在循环系统的周转时间比线性系统的周转时间慢的简单假设下，得到了循环系统和线性系统之间能量的有效分配。线性电子流的能量储存是通过655 nm激发小球藻与短的闪光间隔为0.35秒每闪光。其计算值为0.50 +/- 0.03 eV/hv，接近于氧和NADPH形成的预期值。PSII的能量储存是通过在655 nm处激发小球藻来确定的，其中每次闪光的长闪光间隔为60 s。其计算值为1.07 +/-0.05eV/hv，与处于S态的能量储存和PSII的二次电子受体一致，其中计算的氧化还原能量为1.03eV/hv。在1 μ m的3-（3，4-二氯苯基）-1，1-二甲基脲的存在下，PSII中计算的能量储存仍然是显着的，0.53 +/- 0.04 eV/hv。这可能表明PSII周围存在显著的循环电子流。这些循环流动可能对光合作用中的能量储存有相当大的贡献。
The energy storage of photosynthesis in the green alga Chlorella vulgaris was determined by pulsed, time-resolved photoacoustics. The energy storage of the linear electron transfer process in photosynthesis, of cyclic photosystem (PS) I, and possibly of PSII was determined by selection of excitation wavelength and of flash interval. At 695 nm excitation, a rather large cyclic PSI energy storage of 0.68 +/- 0.04 eV/quantum of energy at 8 ms after a 1-mus flash was obtained. This energy remained the same at flash intervals of 0.35 to 60 s and was independent of the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. We tentatively assign this energy to the ferredoxin-NADP-reductase-ferredoxin and oxidized cytochrome b6/f complexes. An efficient distribution of energy between cyclic and linear systems is obtained with the simple assumption that the turnover time of the cyclic system is slower than that of the linear system. The energy storage of linear electron flow was determined by 655 nm excitation of Chlorella with a short flash interval of 0.35 s per flash. It was calculated to be 0.50 +/- 0.03 eV/hv, close to that expected for oxygen and NADPH formation. The energy storage of PSII is determined by excitation of Chlorella at 655 nm with a long flash interval of 60 s per flash. It was calculated to be 1.07 +/- 0.05 eV/hv, consistent with the energy storage being in S-states and the secondary electron acceptor of PSII with a calculated redox energy of 1.03 eV/hv. In the presence of 1 mum 3-(3,4-dichlorophenyl)-1,1-dimethylurea, the calculated energy storage in PSII is still significant, 0.53 +/- 0.04 eV/hv. This probably indicates a significant cyclic electron flow around PSII. These cyclic flows may contribute considerably to energy storage in photosynthesis.