Spermatogenesis in Pteridophytes: Ultrastructure, Differentiation and Phylogeny

将收集一系列蕨类植物精子发生的比较数据。重点将放在阐明精子发生的超微结构细节和成熟精子细胞的精细结构。三种细胞骨架元素-微管，肌动蛋白和中心蛋白-在分化过程中的作用将通过荧光标记和免疫金定位进行评估。这些数据将与已有的苔藓植物数据进行比较。有鞭毛精子的两个精子植物分类群和两个葡萄植物种类也将被检查。苔藓植物、藻类和种子植物将被用作数据分支分析中的外群。本研究旨在探讨早期蕨类植物之间的系统发育关系，以及它们与藻类、苔藓植物和种子植物谱系之间的系统发育关系。在生物电子显微镜出现之前，早期古藻群多样化的主要二分法在今天仍然是推测性的。这项研究应该能够解决从绿藻到主要现存陆地植物群的早期多样化问题。

Comparative data on spermatogenesis spanning a range of pteridophytes will be collected. Emphasis will be placed on elucidating the ultrastructural details of spermiogenesis and the fine structure of the mature sperm cell. The role of three cytoskeletal elements - microtubules, actin and centrin - in the differentiation process will be evaluated by fluorescent labelling and immunogold-localization. These data will be compared with data already available on the bryophytes. Both taxa of spermatophytes that have flagellated sperm and two species of charaphytes will also be examined. The bryophytes, algae, and seed plants will be used as outgroups in a cladistic analysis of the data. The purpose of this study is resolve phylogenetic relationships among early pteridophytes and between them and the algal, bryophyte and seed plant lineages. The major dichotomies in early diversification of archegoniate groups remain as speculative today as they did before the advent of biological electron microscopy. This study should enable the resolution of early lines of diversification from the green algae to the major extant groups of land plants.