激光共聚焦显微技术在瓮安生物群中的应用

IMAGING PHOSPHATIZED MICROFOSSILS FROM THE EDIACARAN WENG’AN BIOTA USING CONFOCAL LASER SCANNING MICROSCOPY

激光共聚焦显微技术是一种以激光作为激发光源,通过特殊装置"针孔"来过滤离焦光线以提高光学分辨率和对比度的光学成像技术。由于大部分化石不能自发荧光,该技术在古生物学领域尚未实现大范围的应用。但若围岩能自发荧光而与化石之间具有一定衬度,或化石因含特殊成分能在特定波段激光照射下自发荧光而产生结构衬度,则可以运用激光共聚焦显微技术获得在普通光学显微镜及荧光显微镜下难以清晰观察到的信息。为推动激光共聚焦技术在古生物学领域中的应用,文中系统介绍了该技术的原理与使用方法,并以埃迪卡拉纪磷酸盐化特异埋藏的瓮安生物群微体化石为例,展示了该技术在化石成像中的若干优势。实验结果表明,瓮安生物群微体化石因富含磷灰石可自发荧光实现成像,使用激光共聚焦显微成像技术观察瓮安生物群化石薄片不仅可以获得较好衬度,而且还能提高成像的分辨率和清晰度。此外,在化石薄片的厚度范围内还可以实现化石结构三维重建。

Confocal Laser Scanning Microscopy(CLSM) is a fluorescence imaging technique using laser and pinhole to obtain images with higher resolution and better contrast compared to conventional optical microscopy. Although CLSM is a powerful tool applied in many fields such as biology, it has not been widely used in palaeontology yet, because not all fossils are auto-fluorescent. However, if fossil matrix could fluoresce excited by laser beam, sharp contrast between fossils and matrix, or between different parts of fossils may be observed. In these cases, researchers can image inside microstructures with CLSM which can’t be clearly visualized by epifluorescent microscope. In this article, we introduced the principle and work flow of sample preparation and imaged phosphatized microfossils from the Ediacaran Weng’an biota with CLSM. Our results suggest that the CLSM can help to obtain images with higher spatial resolution and better contrast in several cases.