Nanoscale Characterization of Ediacaran Microfossils from Lower Doushantuo Formation Chert Nodules

HAADF-STEM imaging and STEM-EDXS mapping analyses on the FIB ultrathin section reveal that the filaments of <i>Polytrichoides lineatus</i> are filled with numerous spherical or irregular silica particles, which are surrounded by fragments of organic matter and loosely packed. By comparison, the silica particles within the cell wall generally are nano-scale with an average size of 120 ± 40 nm (<i>n</i> = 44, ranging from 60–210 nm) , while those in the cytoplasm are larger with an average size of 1,150 ± 260 nm (<i>n</i> = 46, ranging from 720–1,980 nm) .

针对聚焦离子束（Focused Ion Beam, FIB）制备的超薄切片开展高角环形暗场扫描透射电子显微镜（HAADF-STEM）成像与扫描透射电子显微镜-能量色散X射线能谱（STEM-EDXS）面分布分析，结果显示线叶金发藓（Polytrichoides lineatus）的丝状体内部填充有大量球形或不规则形二氧化硅颗粒，这些颗粒被有机质碎片包裹且排布松散。相较而言，细胞壁内的二氧化硅颗粒多处于纳米尺度，平均尺寸为120 ± 40 nm（样本量n=44，尺寸分布范围为60~210 nm）；而细胞质内的二氧化硅颗粒尺寸更大，平均尺寸为1150 ± 260 nm（样本量n=46，尺寸分布范围为720~1980 nm）。