松辽盆地白垩纪蕨类植物茎干化石解剖及演化研究

蕨类植物叶化石比较常见，而保存解剖结构的茎干化石相对少见。蕨类茎干化石常保存了茎的中柱、髓、皮层以及叶柄基等生物学信息，是整体重建当时植物形态解剖特点不可或缺的重要证据。同时，它们也是研究蕨类植物系统演化的关键证据。我国东北地区是北半球中生代蕨类茎干化石的重要产地之一。目前发现的中生代蕨类茎干化石大部分来自我国东北地区的侏罗系。最近在松辽盆地北部白垩系发现了保存良好解剖结构的蕨类茎干化石群，包括紫萁科、桫椤科和登普斯基蕨科茎干化石。初步研究表明该盆地是世界上蕨类茎干化石类型比较丰富的重要产地。这些新发现的化石为认识白垩纪蕨类植物的多样性和演化过程提供了难得的证据。本研究拟对松辽盆地北部地区新发现的白垩纪蕨类植物茎干化石进行分类学、系统学研究。主要通过当前化石与现存和化石类群解剖特征的对比确定化石的亲缘关系，用支序分析法揭示化石的系统学意义，探讨当前白垩纪植物群与其他地区同时代植物群的关系。

Although leaf fossils of ferns are rather common, stem fossils with anatomical structures are relatively rare. Stem fossils of ferns usually preserve biological information including the stele, pith, cortex and petiole base, which are indispensable evidences for the overall reconstruction of plant morphological and anatomical characteristics at that time. Meanwhile, they are also crucial for studying the phylogenetic evolution of ferns. The Songliao Basin in Northeast China is an important locality of Mesozoic fern stem fossils in the Northern Hemisphere. At present, a large proportion of the Mesozoic fern stem fossils was found from the Jurassic in Northeast China. Very recently, well-preserved fern stem fossils with anatomical structures have been discovered, including stem fossils of Osmundaceae, Cyatheaceae and Tempskyaceae, in the Cretaceous of northern Songliao Basin. Preliminary studies show that the basin is an important locality with abundant types of fern stem fossils in the world. These newly discovered fossils provide very rare evidence for understanding the diversity and evolution of Cretaceous ferns. This research project is intended to study the taxonomy and systematics of the Cretaceous fern stem fossils that have recently been collected from northern Songliao Basin. The phylogenetic relationship of the fossils was revealed mainly by comparing the anatomical characteristics of the present fossils with those of the existing and other known fossil groups. The systematic significance of the fern fossils will be indicated by using cladistic analysis method, while the relationship between the Cretaceous flora in the Songliao Basin and the contemporaneous flora in other regions will also be discussed.