Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Although biochemical features such as secondary phenolics have been used extensively as genotypic indicators in lichen systematics, marcomolecular characteristics such as enzyme electromorphs have thus far been applied to few problems in this field. In this thesis, techniques of isoelectricfocusing and specific enzyme staining were used to produce enzyme electromorph profiles and these were applied to systematic problems in the lichen family Umbilicariaceae. Thalli representing six umbilicate lichen species, Lasallia papulosa (Ach.) Llano, Umbilicaria deusta (L.) Baumg., U. hirsuta (Sw.) Hoffm., U. mammulata (Ach.) Tuck., U. muhlenbergii (Ach.) Tuck. and U. vellea (L.) Ach. were analyzed using these methods.;Reproducible banding patterns were obtained for nine enzymes: isocitrate dehydrogenase (EC, 6-phosphogluconate dehydrogenase (EC, glucose-6-phosphate dehydrogenase (EC, mannitol dehydrogenase (EC, glutamate dehydrogenase (EC, laccase (EC, superoxide dismutase (EC, carboxylesterase (EC and alkaline phosphatase (EC Sample sizes of about 10 thalli per stand were found sufficient to reasonably represent electromorph pattern variation for most enzymes.;Within-stand pattern variation was measured for 48 stands representing the six umbilicate lichen species. These species displayed high degrees of electromorph pattern variation in both apotheciate and sterile stands, and there was no particular relationship between variation and the potential for sexual reproduction in a species. It may be that other phenomena, such as somatic mutations, play a role in maintaining genetic variation in lichen populations which have ceased to reproduce sexually. Apotheciate stands of U. vellea displayed slightly more within-stand pattern variation than sterile stands of this species, which may be an indication that some populational variation in lichens is due to the effects of meiotic recombination.;The multivariate analysis techniques of cluster analysis and principal components analysis were used to summarize the electromorph variation among stands of each species. There was no strong evidence of enzyme variation along strict geographical gradients, but geographically close stands tended to have similar enzyme electromorph patterns.;Affinities among the six species based on enzyme similarities were not wholly consistent with any of the previous classification systems based on morphological characters. However, they did support maintenance of a single genus, at least for the six species tested.



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