Dissertation Research: Endosperm Development, Embryology, and Gametic Fusion in Basal Angiosperms

在科罗拉多大学的导师威廉·弗里德曼博士的指导下，研究生桑德拉·弗洛伊德正在对几种被认为是原始开花植物的植物胚胎的解剖和发育进行深入研究，以记录导致双重受精和这些古代被子植物样本（通常是三倍体）胚乳形成的细胞事件。开花植物，或被子植物，与其他维管植物和种子植物的区别在于一系列看似独特的受精事件，导致植物胚胎的形成，周围的营养组织称为胚乳。弗里德曼博士开创性的显微研究，使用强大的细胞DNA含量的微荧光光谱测量，已经证明了在独特的裸子植物的种子发育过程中类似的事件。弗洛伊德女士正在将研究项目扩展到被子植物的基础谱系，以探索早期被子植物胚胎进化中涉及的解剖和发育的细胞细节。被子植物原始类群胚胎发育的精细形态学或超微结构特征有望帮助解决开花植物早期谱系之间的系统发育关系，这是一个根据许多开花植物的DNA序列数据积累仍未解决的问题。获得此类研究所需的专业设备和技能是本博士论文改进资助的重要属性。

9701210 Friedman Graduate student Sandra Floyd, under the direction of advisor Dr. William Friedman at the University of Colorado, is conducting intensive studies of the anatomy and development of plant embryos in several species of putatively primitive flowering plants, to document cellular events leading to double fertilization and the formation of (usually triploid) endosperm in these exemplars of ancient angiosperms. Flowering plants, or angiosperms, are distinguished from other vascular and seed plants by a series of seemingly unique fertilization events, leading to the formation of the plant embryo with surrounding nutrient tissue called endosperm. Pioneering microscopic research by Dr. Friedman, using powerful microspectrofluorometric measurements of DNA content in cells, has demonstrated similar events in seed development in the peculiar gymnosperms of the order Gnetales. Ms. Floyd is extending the research program to basal lineages of angiosperms, to explore the cellular details of anatomy and development involved in the evolution of early angiosperm embryos. Fine-scale morphological or ultrastructural characters of embryo development in primitive groups of angiosperms hold promise of helping to resolve the phylogenetic relationships among early lineages of flowering plants, a question still unanswered in light of DNA sequence data accumulating for many of these plants. Access to the specialized equipment and skills needed for this kind of research are significant attributes of this doctoral dissertation improvement grant.