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.
