REU: Taxonomy, Systematics and Evolution of Coleochaete

生物学家多年来一直推测，现代陆地植物一定是从某种水生绿藻进化而来的。像威斯康星大学的琳达·格雷厄姆博士这样的研究人员提出了形态和发育证据，证明轮藻的四个属--轮藻属Chara、Nitella、Coleochaete和Chaetosphaeridium--与陆地植物最相似，很可能是高等植物中最接近的藻类近亲。在对其中两个属的持续研究中，格雷厄姆博士正在研究细胞核中DNA数量的新特征，测量不同环境条件下的细胞大小，并测试在陆地植物中常见但在大多数藻类中很少或根本不存在的特殊化合物(痂和孢粉蛋白)的存在。这些研究的数据将证实或驳斥轮藻与陆地植物关系密切的观点，也将提供有助于识别鞘毛虫属和毛壳藻属物种的分类学特征。

Biologists have speculated for years that modern land plants must have evolved from some group of aquatic green algae. Researchers like Dr. Linda Graham at the University of Wisconsin have presented morphological and developmental evidence that the four genera of charophyte algae, Chara, Nitella, Coleochaete, and Chaetosphaeridium, are most similar to land plants and are likely the closest living algal relatives of higher plants. In continuing studies of two of these genera, Dr. Graham is investigating new featurs of DNA quantity in cell nuclei, measuring cell size under varying environmental conditions, and testing for the occurrence of specialized compounds (callose and sporopollenin) common in land plants but rare to absent in most algae. Data from these studies will either corroborate or refute the idea that charophytes are close to land plants, and will also provide taxonomic characters aiding in the recognition of species within the genera Coleochaete and Chaetosphaeridium.