|
|
Evolution of nuclear DNA content variation in the genus Mallomonas and its ecophysiological consequences
Čížková, Natálie ; Čertnerová, Dora (advisor) ; Trávníček, Pavel (referee)
The variability of genome size among eukaryotes and its consequences remains largely unknown. This is particularly true for unicellular eukaryotic organisms, also known as protists, whose nuclear DNA content is still largely unexplored. Across plants or animal studies, it has been repeatedly demonstrated that genome size is closely associated with cell size and may also be related to other eco-physiological parameters, such as growth rate, metabolic rate, or life strategy. In protists, the cell represents their entire body, allowing for the direct assessment of the impact of genome size on organismal phenotypic traits. In this thesis, with the use of flow cytometry, the absolute amount of nuclear DNA was estimated for 165 strains of the genus Mallomonas (Chrysophyceae) belonging to 64 species, revealing diversity in nuclear DNA content for nearly 1/4 of the globally recognized diversity of this genus. Based on the obtained data, up to 100-fold variability in nuclear DNA content was found across Mallomonas species (0.12 pg - 11.4 pg). Detected intraspecific variability in nuclear DNA content suggests the influence of various evolutionary mechanisms, for example multiple-fold difference in DNA content (even within closely related species) suggest frequent polyploidization in the genus Mallomonas....
|
|
|
Biodiversity-productivity relationship in desmid communities
Škvorová, Marie ; Škaloud, Pavel (advisor) ; Nedbalová, Linda (referee)
This thesis deals with biodiversity-productivity relationship in desmid communities. Biodiversity is found to be changing globally. The biodiversity-productivity relationship is therefore an important research topic. Three aspects of biodiversity are thought to play an important role: species richness, functional diversity and phylogenetic diversity. It is known that in general, productivity is positively correlated with diversity. Interactions between different metrics of biodiversity are known less. Existing studies have shown that these interactions might be present. In general, biodiversity-productivity studies were mostly focused on plants. Less is known about other organisms, including algae. In this work I explore the relationship between overyielding and functional or phylogenetic diversity on a species richness gradient of desmid communities. I conducted an artificial biodiversity- ecosystem functioning experiment using combinations of two to 12 desmid species. Communities differed in the diversity aspects. I had measured the biomass growth. For the analysis, I have used the overyielding index, which is based on a comparison of a polyculture production with the production expected based on monoculture yields. The relationship of overyielding on functional diversity depended on species...
|
guest ::
