Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502 Japan.
Plant Cell Physiol. 2010 Feb;51(2):225-38. doi: 10.1093/pcp/pcp182. Epub 2009 Dec 18.
In this study, we produced selective images of photosystems in plant chloroplasts in situ. We used a spectroimaging microscope, equipped with a near-infrared (NIR) laser that provided light at wavelengths mainly between 800 and 830 nm, to analyze chlorophyll autofluorescence spectra and images from chloroplasts in leaves of Zea mays at room temperature. Femtosecond laser excitation of chloroplasts in mesophyll cells revealed a spectral shape that was attributable to PSII and its antenna in the centers of grana spots. We found that a continuous wave emitted by the NIR laser at a wavelength as long as 820 nm induced chlorophyll autofluorescence with a high contribution from PSI through a one-photon absorption mechanism. A spectral shape attributable to PSI and its antenna was thus obtained using continuous wave laser excitation of chloroplasts in bundle sheath cells. These highly pure spectra of photosystems were utilized for spectral decomposition at every intrachloroplast space to show distributions of PSI and PSII and their associated antenna. A new methodology using an NIR laser to detect the PSI/PSII ratio in single chloroplasts in leaves at room temperature is described.
在这项研究中，我们在原位产生了植物叶绿体中光系统的选择性图像。我们使用配备近红外（NIR）激光的光谱成像显微镜，该激光提供的波长主要在 800 到 830nm 之间，以分析玉米叶片叶绿体在室温下的叶绿素自发荧光光谱和图像。飞秒激光激发叶肉细胞中的叶绿体，揭示了一种光谱形状，可归因于 PSII 及其在粒状斑点中心的天线。我们发现，NIR 激光在长达 820nm 的波长下发出的连续波通过单光子吸收机制诱导叶绿素自发荧光，其中 PSI 的贡献很高。因此，使用连续波激光激发束鞘细胞中的叶绿体，获得了可归因于 PSI 和其天线的光谱形状。这些高度纯净的光系统光谱用于在每个类囊体空间进行光谱分解，以显示 PSI 和 PSII 及其相关天线的分布。描述了一种在室温下使用 NIR 激光检测单个类囊体中 PSI/PSII 比值的新方法。
