Dissertation Research: Systematic Analysis of Isoetes in North America

9321767希林在田纳西大学教职顾问爱德华·席林博士的指导下，研究生罗伯特·达夫正在使用分子和形态分析来研究原始的、含孢子的植物水苏子的北美物种。所谓的刺藻(由于它们的小叶子长得像羽毛一样)生长在池塘、溪流或泉水池中，通常生长在分散在整个大陆的小而高度受限的种群中。目前在北美已知的种类约为25种，全世界约有150种。昆布属的化石记录表明，该属是古老的；有一些证据表明，它是最原始的维管植物谱系中现存的三个属之一。来自叶绿体DNA限制性内切酶图谱和核糖体DNA核苷酸测序的新分子数据将与来自形态和染色体的传统分类信息进行比较，以建立北美物种系统发育关系的可靠假说，进而探索特征进化和地理分布模式。从DNA分析中产生新的分子证据，并将这些信息与传统的形态特征相结合，正在重振植物分类学研究。通过这次调查，人们将更好地了解等温线。

9321767 Schilling Under the direction of faculty adviser Dr. Edward Schilling at the University of Tennessee, graduate student Robert Duff is employing molecular and morphological analyses to study the North American species of the primitive, spore-bearing plant Isoetes. The so-called quillworts (from the quill-like resemblance of their small leaves) grow in ponds, streams, or vernal pools, usually in small and highly restricted populations, scattered across the continent. Currently about 25 species are recognized in North America, and about 150 total in the world. The fossil record of quillworts shows the genus to be ancient; there is some evidence that it is one of the three surviving genera of the most primitive lineage of vascular land plants. New molecular data from chloroplast DNA restriction-enzyme mapping and from nucleotide sequencing of nuclear ribosomal DNA will be compared to traditional taxonomic information from morphology and chromosomes to develop a robust hypothesis of phylogenetic relationships of the North American species, and then to explore patterns of character evolution and geographical distribution. The generation of new molecular evidence from DNA analyses and the integration of that information with traditional morphological characters are revitalizing the taxonomic study of plants. Isoetes will be better understood as a result of this investigation.