Dissertation Research: Systematic Analysis of Isoetes in North America

小行星9321767 在田纳西大学教授顾问Edward Schilling博士的指导下，研究生Robert Duff正在利用分子和形态学分析来研究北美原始的孢子植物Isopropyl的物种。 所谓的鹅掌楸（从羽毛状相似的小叶子）生长在池塘，溪流或春天的池塘，通常在小和高度有限的种群，分散在整个大陆。 目前在北美约有25种，全世界约有150种。 鹅掌楸的化石记录显示该属是古老的;有证据表明它是维管陆生植物最原始谱系中幸存的三个属之一。 叶绿体DNA限制酶图谱和核核糖体DNA核苷酸测序的新分子数据将与形态学和染色体的传统分类学信息进行比较，以建立北美物种系统发育关系的可靠假设，然后探索特征进化和地理分布的模式。 从DNA分析中获得的新的分子证据以及这些信息与传统形态特征的整合正在使植物分类学研究重新焕发活力。 通过这项研究，将更好地了解异戊四醇。

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.