Diatoms are a major group of microalgae in marine and freshwater environments. To utilize the light energy in blue to green region, diatoms possess unique antenna pigment-protein complexes, fucoxanthin chlorophyll a/c-binding proteins (FCPs). Depending on light qualities and quantities, diatoms form FCPs with different energies: normal-type and red-shifted FCPs. In the present study, we examined changes in light-harvesting and energy-transfer processes of a diatom Chaetoceros gracilis cells grown using white- and single-colored light-emitting diodes (LEDs), by means of time-resolved fluorescence spectroscopy. The blue LED, which is harvested by FCPs, modified energy transfer involving CP47, and suppressed energy transfer to PSI. Under the red-LED conditions, which is absorbed by both FCPs and PSs, energy transfer to PSI was enhanced, and the red-shifted FCP appeared. The red-shifted FCP was also recognized under the green- and yellow-LEDs, suggesting that lack of the shorter-wavelength light induces the red-shifted FCP. Functions of the red-shifted FCPs are discussed.

中文翻译：

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硅藻 Chaetoceros gracilis 的光捕获和能量转移过程对不同光质量的适应。

硅藻是海洋和淡水环境中的主要微藻群。为了利用蓝色到绿色区域的光能，硅藻具有独特的触角色素蛋白复合物，即岩藻黄质叶绿素 a/c 结合蛋白 (FCP)。根据光的质量和数量，硅藻形成具有不同能量的 FCP：正常型和红移 FCP。在本研究中，我们通过时间分辨荧光光谱检查了使用白色和单色发光二极管 (LED) 生长的硅藻薄壁角藻细胞的光捕获和能量转移过程的变化。由 FCP 收集的蓝色 LED，修改了涉及 CP47 的能量转移，并抑制了向 PSI 的能量转移。在被 FCPs 和 PSs 吸收的红色 LED 条件下，增强了向 PSI 的能量转移，并且出现了红移的FCP。在绿色和黄色 LED 下也识别出红移的 FCP，这表明缺乏较短波长的光会导致红移的 FCP。讨论了红移 FCP 的功能。