Thesis (Inaug.-Diss.)--Universität Leipzig, 1902? / Vita. Bibliography: p. [50]-51.

No description available.

On the basis of three morphological characters (e.g., filament, width, chloroplast number, and type of cell end wall), six filament types of Spirogyra were collected along Bear Creek in the Santa Catalina Mountains near Tucson, Arizona. The occurrence and distribution of filament types showed seasonal and geographical patterns. Filaments were more frequently collected in early summer from pools at lower elevation. Growth of Spirogyra may be influenced by water temperature, pH, and water amount. Most filaments occurred more abundantly while water temperture and pH were relatively high. The number of filament types was greatest at sites with a semi-permanent water supply rather than in temporary and permanent pools. Of the six types of Spirogyra, Type V showed morphological and genetic changes through vegetative growth and sexual reproduction in a clonal culture in the laboratory. After 33 months culturing, a narrower filament-width group (Group II, 22.0 ± 1.1 μm) was produced in the original clone (Group I, 30.9 (+OR-) 0.7 μm). Groups I and II were homothallic and sexually compatible. Zygospores from the cross of I x II yielded germlilngs of Groups I, II, III (27.2 ± 1.0 μm) and a binucleate IV (44.9 ± 0.8 μm). Chromosome counts were: Group I (24), Group II (12), Group III (18), and Group IV (24, one nucleus). Relative nuclear-DNA fluorescence values increased as filament width and chromosome number increased. Cytologically, Group I is a tetraploid, Group II a diploid, and Group III a triploid. Systematically, Groups I, II and III key out to pirogyra singularis, S. communis, and S. fragilis, respectively, using Transeau's monograph on Zygnemataceae. These species are interpreted to be a species complex of S. communis (whose name has priority) with the ancestral haploid (x = 6) missing. Five years after isolation of the original strain in this species complex filaments corresponding to Groups I and II were found at the original collection site. The two field-collected groups were indistinguishable from the laboratory species complex in morphology and chromosome number. Homothallic conjunction within two field width groups yielded progeny similar to those from homothallic conjunction of groups in the laboratory species complex. Filament widths of progeny were generally within the width limits of respective parental groups. The four intergroup crosses between laboratory and field width groups were successful and yielded progeny representing Groups I, II, and III. The similarities in morphology, chromosome numbers, and reproductive behavior of laboratory and field width groups imply that the laboratory species complex of S. communis has a natural counterpart in the field.

Thesis (M.S.)--University of North Carolina Wilmington, 2007. / Includes bibliographical references (leaves: 43-46)

Phytohormone auxin plays an important role in regulating plant development. Directional (polar) cell-to-cell auxin transport creates auxin gradients within plant tissues, which trigger a specific developmental response. The vast majority of available data concerns angiosperms. Lower land plants have been much less explored in this regard, but the important auxin-related mechanisms (including polar auxin transport) are already present in mosses. To uncover the origins of auxin action, one must focus on green algae, especially of clade Streptophyta, which are the direct ancestors of all land plants. In this study, the possible effects of auxins, both native and synthetic, were investigated on two algae: basal, unicellular Chlorella lobophora and advanced, filamentous Spirogyra sp. The latter received comparably more attention, since it belongs to a clade now acknowledged as a sister group to land plants. Chlorella lobophora culture growth was irresponsive to synthetic auxin NAA. The average Spirogyra sp. cell length was, however, changed by auxins at high concentrations. By conducting accumulation assays of radioactively labelled auxins and HPLC analysis, auxin metabolism and transport was investigated in Spirogyra sp. This alga was able to metabolize the plant-native IAA, but not synthetic auxins...