CEA, DSV, IBEB, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108 Saint-Paul-lez-Durance, France.
Plant J. 2011 Sep;67(6):1103-15. doi: 10.1111/j.1365-313X.2011.04646.x. Epub 2011 Jul 1.
Plants, like almost all living organisms, spontaneously emit photons of visible light. We used a highly sensitive, low-noise cooled charge coupled device camera to image spontaneous photon emission (autoluminescence) of plants. Oxidative stress and wounding induced a long-lasting enhancement of plant autoluminescence, the origin of which is investigated here. This long-lived phenomenon can be distinguished from the short-lived chlorophyll luminescence resulting from charge recombinations within the photosystems by pre-adapting the plant to darkness for about 2 h. Lipids in solvent were found to emit a persistent luminescence after oxidation in vitro, which exhibited the same time and temperature dependence as plant autoluminescence. Other biological molecules, such as DNA or proteins, either did not produce measurable light upon oxidation or they did produce a chemiluminescence that decayed rapidly, which excludes their significant contribution to the in vivo light emission signal. Selective manipulation of the lipid oxidation levels in Arabidopsis mutants affected in lipid hydroperoxide metabolism revealed a causal link between leaf autoluminescence and lipid oxidation. Addition of chlorophyll to oxidized lipids enhanced light emission. Both oxidized lipids and plants predominantly emit light at wavelengths higher than 600 nm; the emission spectrum of plant autoluminescence was shifted towards even higher wavelengths, a phenomenon ascribable to chlorophyll molecules acting as luminescence enhancers in vivo. Taken together, the presented results show that spontaneous photon emission imaged in plants mainly emanates from oxidized lipids. Imaging of this signal thus provides a simple and sensitive non-invasive method to selectively visualize and map patterns of lipid oxidation in plants.
植物与几乎所有生物体一样，会自发地发射可见光光子。我们使用高灵敏度、低噪声的冷却电荷耦合器件相机来成像植物的自发光子发射（自发发光）。氧化应激和创伤会导致植物自发发光的持久增强，我们在这里研究了其起源。这种持久的现象可以与源自光合作用系统内电荷复合的短寿命叶绿素发光区分开来，通过将植物在黑暗中预适应约 2 小时，可以实现这种区分。我们发现，溶剂中的脂质在体外氧化后会发出持久的发光，其发光时间和温度依赖性与植物自发发光相同。其他生物分子，如 DNA 或蛋白质，在氧化后要么不产生可测量的光，要么产生迅速衰减的化学发光，这排除了它们对体内发光信号的显著贡献。对在脂质过氧化物代谢中发生突变的拟南芥突变体的脂质氧化水平进行选择性操纵，揭示了叶片自发发光与脂质氧化之间的因果关系。向氧化脂质中添加叶绿素会增强发光。氧化脂质和植物主要在波长高于 600nm 的波长处发射光；植物自发发光的发射光谱向更高的波长移动，这一现象归因于叶绿素分子在体内作为发光增强剂的作用。总之，所呈现的结果表明，在植物中成像的自发光子发射主要源自氧化脂质。因此，这种信号的成像提供了一种简单、敏感、非侵入性的方法，可用于选择性地可视化和绘制植物中脂质氧化的模式。
