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Polyploidy in natural populations of Arabidopsis
Bayerová, Jana ; Kolář, Filip (advisor) ; Čertner, Martin (referee)
This thesis deals with polyploidy in natural populations in the genus Arabidopsis. It summarizes information about the relatives of Arabidopsis thaliana, a prominent model organism for research on genetics and plant physiology. Literature shows that polyploidy affects ecological, climate and soil requirements, as well as mating system of the plants in genus Arabidopsis. Most of the published studies is focused on the study of artificial polyploid hybrids created by crossing experiments - especially with the Arabidopsis thaliana. In contrast, my thesis deals with the natural polyploids observed within the genus. In particular, I focus on the nearly unstudied di- polyploid complex of high-altitude populations of Arabidopsis arenosa in the Tatra Mountains. This complex represents a unique model system for studying the effects of polyploidization in the wild - thanks to the high morphological and ecological diversity of the hybrids, and to the relative genetic similarity of the parental populations. Key words: allopolyploid, Arabidopsis, Arabidopsis arenosa, autopolyploid, hybridization, polyploidization, Tatry
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Biosystematic revision of the Spergularia echinosperma complex
KÚR, Pavel
This thesis is focused on the biosystematic study of the Central-European endemic Spergularia echinosperma. With the combined use of morphometric analyses, genome size measurements and molecular tools, the taxonomic issues associated with this species have been clarified. The existence of S. kurkae, a stable allotetraploid hybrid between diploid S. echinosperma and tetraploid S. rubra, has been proven. Based on several lines of evidence, including distinct morphological separation and frequent occurrence in the absence of the parental species, treating S. kurkae as a separate species is proposed. In addition, two infraspecific taxa within S. echinospermaS. echinosperma subsp. echinosperma and S. echinosperma subsp. albensisdiffering in distributions and ecology have been described. A complete revision of the localities of S. echinosperma, S. kurkae and S. rubra in the Czech Republic is also presented. Furthermore, the development of 16 polymorphic microsatellite loci for S. echinosperma is reported.
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