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Molecular phylogeny and evolutionary trends in Hieracium (Asteraceae, Lactuceae)
Krak, Karol ; Fehrer, Judith (advisor) ; Zozomová, Judita (referee) ; Nieto Feliner, Gonzalo (referee)
The hawkweed subgenus Hieracium s. str. is notoriously known for its extreme morphological variability and variation in ploidy levels that is associated with differences in modes of reproduction. Extensive past hybridization is supposed for the subgenus, but recent hybridization was evidenced only in few cases. The subgenus attracts the attention of botanists already for more than a century. Therefore the species diversity is largely examined and the taxonomy of the subgenus is well elaborated, although several contradictory taxonomic concepts exist. However the relationships among the species are unknown and haven't been studied yet. The investigation of these relationships from a phylogenetic perspective using molecular approaches was the main aim of the presented thesis. Basic species (both diploid and polyploid), representing morphologically unique taxa, that are supposed to be the basic evolutionary units of the subgenus were studied. The sequences of two intergenic spacers of the cpDNA (trnT-trnL and trnV-ndhC) and the external transcribed spacer of the nuclear ribosomal DNA (nrDNA ETS) were analyzed. Moreover, three new low-copy nuclear markers with higher variability than nrDNA and cpDNA markers were developed and their suitability for phylogenetic studies in Hieracium s. str. was...
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The importance of polyploidization in the evolution of grasses of the tribe Triticeae
Papoušek, Lukáš ; Urfus, Tomáš (advisor) ; Chrtek, Jindřich (referee)
Polyploidization, as a process of chromosome set multiplication, represents one of the most significant forces that shaped the evolution of angiosperms. Therefore, understanding the mechanisms of polyploidization is also important. It most often originates through unreduced gametes (less so through somatic polyploidization). Autopolyploids are the result of polyploidization within one species, or population, while the formation of allopolyploids is preceded by interspecific hybridization. Polyploidization also played a major role in the tribe Triticeae (Poaceae), which includes economically significant crops (wheat, rye, and barley). The taxonomy ofthe entire tribe, especially the generic concept, has been based on genomic concepts in recent decades. However, taxonomy is considerably complicated, particularly due to hybridization, or allopolyploidization. The result of allopolyploidization and even hybridization itself is a reticulate pattern, and it is not at all easy to determine the boundaries between taxa, even at the generic level. Triticum aestivum can be considered a model species for the study of allopolyploidy, both due to its economic significance and its origin through several rounds of hybridization events. Although allopolyploidy prevails, autopolyploidy can be encountered to a lesser...
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Polyploidization and hybridization as evolutionary drivers in the Medicago sativa group
Peřina, Ondřej ; Kolář, Filip (advisor) ; Bartolić, Paolo (referee)
This bachelor's thesis addresses polyploidy induced by whole genome duplication and its consequences to the evolution of Medicago sativa species complex, i.e. wild relatives of an important forage crop alfalfa. This complex encompasses several interfertile taxa naturally occurring as diploid (2n = 16) or tetraploid (2n = 32) cytotype. Several recently conducted studies attempted to explain origin and evolution of this complex and relationships among its members using modern molecular methods, however, the results are still fragmentary and inconclusive. Two most widespread members of the complex: purple flowering Medicago sativa and yellow flowering Medicago falcata are genetically differentiated both at diploid and tetraploid level, what is supporting their recognition as distinct taxa. Furthermore, it has been shown that tetraploid M. sativa subsp. sativa is an autopolyploid that originated from diploid M. sativa subsp. caerulea by intraspecific whole genome duplication. On the other hand, the origin of tetraploid M. falcata seems to be more complex, presumably involving autopolyploidization followed by past introgression from Medicago prostrata. Most of the studies concerning this topic were performed on accessions, which are sometimes of uncertain ploidy and origin, obtained from germplasm...
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Genome duplication in Stellaria genus - the more, the merrier? Link between ploidy levels and sexual polymorphism.
Krtilová, Eliška ; Slovák, Marek (advisor) ; Prančl, Jan (referee)
Polyploidization in angiosperms, a well-documented phenomenon, often correlates with a diversity of reproductive strategies, including sexual polymorphism, impacting their evolution and expression. This relationship is particularly intriguing in high polyploids, where the interaction can be complex yet largely enigmatic. We investigated the connection between high polyploidy and sexual polymorphism in Stellaria palustris (Caryophylaceae), a species complex with exceptionally high levels of polyploidy exceeding decaploids and reportedly exhibiting variable sexual expression. To broaden our analysis, we included its relatives, diploid-tetraploid S. graminea and diploid S. longifolia. Our study focused on Central and Northern Europe, utilizing various methodological approaches, including genome size estimation, chromosome counting, genetic analyses based on Sanger sequencing, and evaluating floral organ variability and sexual expression. Major hypotheses examined associations between ploidy level and latitude, as well as ploidy level and sexual polymorphisms. Chromosome counts of S. palustris ranged from 2x = 154 - 208, corresponding to 2n=12x, 14x, and 16x, while for S. graminea and S. longifolia, we confirmed their originally known ploidies. Although chromosome counts did not unambiguously reflect...
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Alternative powertrains of vehicles
Filip, Vojtěch ; Kučera, Pavel (referee) ; Píštěk, Václav (advisor)
The aim of this thesis is the analysis of most common alternative drive systems currently used in cars, their comparison with the current gasoline and diesel engines. Familiarization with the technical solutions of drives, their categorization into several groups according to the specific key features. It also deals the most important components of an alternative fuels automobiles, respecting their strengths and also weaknesses that currently hinder expansion of these propulsions, economically as well as technically.
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Modern hybrid drive of passenger vehicles
Švoma, Jan ; Blaťák, Ondřej (referee) ; Vančura, Jan (advisor)
This bachelor thesis deals with the current hybrid-drives in passenger cars. The thesis contains the categorization of hybrid systems according to structure and use. It also discusses the analysis of individual components and describes their suitability for use in different situations. It is focused on current offering of hybrid vehicles and development opportunities. At the end of are evaluated economic aspects and prospects for the use of these systems in the future.
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Evolution of intraspecific diversity of invasive pathogen of alder Phytophthora ×alni
Pecka, Štěpán ; Koukol, Ondřej (advisor) ; Sedlářová, Michaela (referee)
Phytophthora alni s. l. (Peronosporomycetes: Stramenopila) is an invasive pathogen causing phytophthora root and collar rot in alders. It has been known from Europe since the '90s and from the Czech Republic since 2001. Three species were found are known within species complex P. alni s. l. Two of these species hybridized in Europe and created third triploid species called Phytophthora ×alni (Phytophthora alni subsp. alni). Dozens of genotypes have been identified with the help of microsatellites in previous studies, nevertheless only one genotype (Pxa-1) was dominating and most of other genotypes were closely related to it. The trend of increasing or decreasing incidence of this genotype differed among these studies. This thesis compares changes in the P. ×alni population in Vltava basin over the last 14 years during which a significant decrease in number of available hosts of this pathogen took place. Multilocus genotypes were determined using a set of 10 microsatellite markers. Among the 94 P. ×alni isolates reliably genotyped, 23 were of different genotypes. None of these genotypes, however, were found on the same localities repeatedly (except the dominant genotype). Incidence of the dominant genotype increased over time (from 63 % to 86 %). Most of the other genotypes were only slightly...
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Commercialization of civil society organizations from the perspective of managers in the field of elderly care in the Czech Republic
Čechurová, Helena ; Šťovíčková Jantulová, Magdaléna (advisor) ; Moree, Dana (referee)
The diploma thesis focuses on the commercialization of civil society organizations (CSOs), specifically the institutional isomorphism that makes CSOs "business like" as well as the relationship between CSOs and the commercial sector in the context of commercialization. The purpose of this thesis is to gain an understanding of the manager's perspectives representing CSOs in the field of elderly care in the Czech Republic, with a particular emphasis on the institutional isomorphism and the relationships mentioned above. The findings of the study were obtained from narrative and semi-structured interviews with seven selected managers in the field of elderly care in the Czech Republic. The findings indicate that the participants regard the institutional isomorphism (coercive) as unfair and meaningless; patchy and outdated. The examination of the level of relationships between CSOs and the commercial sector resulted in the Relationships Typology. The typology presents three foundations based on need, reputation, and crisis that have been identified as the foundations for developing relationships between CSOs and the commercial sector. Each foundation conceals the unique nature of relationships visible in commercialized CSOs as reflected by selected managers. Key words: business-like, hybridization,...
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Evolution of the genus Malus with a particular reference to old and local cultivars
Polcar, Václav ; Urfus, Tomáš (advisor) ; Macková, Lenka (referee)
The following work deals with the genus Malus in terms of the significant diversity that this genus represents. It summarizes a basic knowledge about the taxonomic position and world centers of the genus evolution. Part of the thesis also discussed reproductive mechanisms as a source of the genus diversity. The thesis then focuses on the species Malus domestica, its evolution and the hybrid origin. In this context, old varieties of apple trees, their significance and pomologically important regions of the Czech Republic are presented. An integral part of this work is also devoted to the protection of old varieties, its limits and possibilities. The protection of old varieties also encompasses the extensive orchard as an important agroecosystem. Finally, different Czech regions are compared with respect to the quantity of reported old varieties.
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Hybridization as a source of threat to Urtica kioviensis
Pekařová, Michaela ; Urfus, Tomáš (advisor) ; Štěpánek, Jan (referee)
Hybridization can have a negative impact on native taxa, which means a risk to plant biodiversity. Urtica kioviensis (2x) is a rare species of that grows in mixed populations together with two cytotypes (2x and 4x) of the closely related taxon Urtica dioica (stinging nettle). The presence of hybrids has been described in the past. Here I studied hybridization at localities in the Czech Republic (PR Plačkův les a říčka Šatava, NPR Ranšpurk), Slovakia (PR Jurský Šúr), and Hungary (Kóny, Fehér-tó). These taxa and their hybrids were studied by flow cytometry and morphometric analysis. Both methods provided evidence of ongoing hybridization. The continuous pattern at the diploid level suggests homoploid hybridization and subsequent introgression affecting mainly U. kioviensis. The possibility of backcrossing at the diploid level was also confirmed by analyses of pollen fertility or staining. Triploid individuals were also detected, showing differences in relative genome sizes and different positions relative to the parental taxa in morphometric analyses. Based on these results, it's not possible to reliably determine their origin. Heteroploid hybridization is likely to occur, but its presence cannot be definitely confirmed or excluded. Hybrids are common in mixed populations of U. kioviensis and mean a...
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