Wang X
Department of Geological Sciences and Florida Museum of Natural History, University of Florida, Gainesville, FL 32611-7800, USA.
Tissue Cell. 2004 Oct;36(5):351-60. doi: 10.1016/j.tice.2004.06.002.
Usually only an organism with hard parts may be preserved in the fossil record. Cytoplasm, which is a physiologically active part of a plant, is rarely seen in the fossil record. Two Cretaceous plant fossils older than 100 million years with exceptional preservation of cytoplasm are reported here. Some cytoplasm is well preserved with subcellular details while other cytoplasm is highly hydrolyzed in the cortex of the same fossil even though both of preservations may be less than 2 microm away. The unique preservation pattern, sharp contrast of preservation in adjacent cells and the exceptional preservation of cytoplasm in the cortex suggest that lightning should play an important role in the preservation of cytoplasm and that cytoplasmic membranes may be more stable than the cell contents. Interpreting the preservation needs knowledge scattering in several formerly unrelated fields of science, including geophysics, botany, biophysics, cytology and microwave fixation technology. This new interpretation of fossilization will shed new light on preservation of cytoplasm and promote cytoplasm fossils from a position of rarity to a position of common research objects available for biological research. The importance of the identification of cytoplasm in fossil lies not in itself but in how much it influences the future research in paleobotany.
通常只有具有硬体部分的生物才能保存在化石记录中。细胞质作为植物生理活性部分，在化石记录中很少见。本文报道了两块距今超过1亿年的白垩纪植物化石，其细胞质保存异常。在同一化石的皮层中，有些细胞质保存完好，具有亚细胞细节，而另一些细胞质则高度水解，尽管两者的保存距离可能不到2微米。这种独特的保存模式、相邻细胞保存情况的鲜明对比以及皮层中细胞质的异常保存表明，闪电在细胞质的保存中应发挥重要作用，并且细胞质膜可能比细胞内容物更稳定。对这种保存现象的解读需要综合多个以前互不相关的科学领域的知识，包括地球物理学、植物学、生物物理学、细胞学和微波固定技术。这种对化石形成的新解读将为细胞质的保存带来新的启示，并推动细胞质化石从罕见地位转变为可用于生物学研究的常见研究对象。化石中细胞质鉴定的重要性不在于其本身，而在于它对古植物学未来研究的影响程度。
