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Genome size in plants varies greatly; in angiosperms this variability can make a 2400- fold difference. This is why the subject of many studies is the attempt to explain these differences in various contexts. One of these is the phylogenetic viewpoint, which studies the relationships between genome size and different taxonomic groups. Many studies have been published so far which explore the plants of the temperate zone; there are however very few studies investigating genome size in tropical plants. For this reason, the subject of this thesis is the analysis of genome size in the pantropical family Costaceae Nakai. This family presently includes seven genera: Monocostus K.Schum., Dimerocostus Kuntze, Costus L., Paracostus C.D.Specht, Chamaecostus C.D.Specht & D.W.Stev, Hellenia Retz. and Tapeinochilos Miq., counting altogether about 300 species. The family is sister to the family Zingiberaceae, which has been notably better explored due to its economic importance. One of the aims of this thesis was a partial revision of the phylogeny published by Specht (2006). Molecular methods were used to analyse the phylogenetic relationships; these methods included classical sequencing of the trnL-F region and next-generation sequencing, where probes designed in advance were used to obtain the targeted genes....

Polyploidization is a key mechanism of rapid speciation, with many phenotypic consequences which extent, however, is poorly understood. A deeper understanding of the evolutionary implications of genome duplication is limited due to lack of knowledge of the links between changes in genome, the phenotype of the individual and environmental constraints. Natural lineages closely related to model species represent the ideal systems for addressing such questions. The thesis is thus focuses on highly promising yet overlooked di-polyploid system within Arabidopsis genus. In the western Carpathians morphologically distinct populations of diploid and tetraploid plants of Arabidopsis arenosa grow along a marked altitudinal gradient. Using high-throughput DNA sequencing, measuring morphological characteristics and collecting ecological data of high alpine and foothill populations I try to reveal main trends of genetic and morphological variability of these populations. Additionaly, using morphometrics of natural and experimentally planted populations we want to test the hypothesis whether morphological divergence of alpine and foothill populations has a genetic basis or is driven by phenotypic plasticity. The presented thesis is an important multidisciplinary combination of genetic research on natural related of model...

Sturgeons (Chondrostei: Acipenseriformes) display markedly disjunct distributions with a wide occurrence in the northern hemisphere. Their unique benthic specializations, conserved morphology, evolutionary age, the variation in their basic diadromous life history, and the large public interest due to their near extinction or critically endangered status make sturgeons and paddlefishes one of the most interesting group of vertebrates. In addition to that, ploidy diversity of Acipenseriformes possessing three ploidy groups having ~ 120 chromosomes, ~ 240 ? 270 chromosomes and ~ 360 chromosomes provides unique model for investigation of evolutionary processes which were going through the genome duplication events. Sturgeons are also notoriously known for their strong propensity to interspecific and intergeneric hybridization which can result in hybrids with various ploidy levels. All these facts make sturgeon genetics and cytogenetics a thriving but also complicated area for research. In the present work, the role of genome duplication and functional reduction evens in evolution of sturgeon species as well as sturgeons? ploidy levels and ploidy relationships among Acipenseriformes were investigated using molecular markers. In addition to that, clarification of origin of abnormal ploidy levels and observation of segregation pattern of microsatellite alleles in the course of hybridization of polyploid sturgeon species were included into this study. With regard to the all considerations and observations provided by this study we concluded that evolution of sturgeon species is still widely dynamic and ongoing process which might goes through the allopolyplodization as well as autopolyplidization events.

The main drivers of microevolution in the genus Sorbus are interspecific hybridisation and polyploidy. The fate of new hybrid and polyploid taxa is determined by their mode of reproduction. Especially apomixis could be very advantageous for these new taxa. The S. aria agg. (subg. Aria) plays an important role within the genus since its members are involved in all hybridisation events and thereby is responsible for the substantial part of variation of the genus. Flow cytometry, molecular markers and multivariate morphological analyses were employed to evaluate the processes generating the variability in the S. aria group. Three ploidy levels were detected among species from subg. Aria in the Czech Republic. All of them could be found in the South Moravia, whereas only tetraploids occur in the Bohemia region. Moreover, most of the Czech taxa (5 out of 7) grow also only in the South Moravia which is therefore considered as a centre of diversity of the genus Sorbus in the Czech Republic. Flow cytometry seed screen revealed 7 modes of reproduction among the individuals from S. aria agg. A wide range of sexual and apomictic types of reproduction including reduced and unreduced gametes was detected. All of the diploid individuals are completely sexual. Among polyploid taxa, most of the species are...

Eight of fifteen species in genus Anthoxanthum (Poaceae) can be found in Europe. Five of them are perennials forming A. odoratum complex, the remaining three are annual, more or less mediterranean taxa (A. aristatum, A. ovatum and A. gracile). Within the A. odoratum s. l. complex the following taxa are distinguished: widely spread A. odoratum s. str. (4x; 2n = 20), arcto-alpine A. alpinum (2x a 4x; 2n = 10 and 20), Madeiran endemic species A. maderense (2x; 2n = 10), endemic species of Balkan mountains A. pauciflorum (2x; 2n = 10) and the Iberian peninsula endemic A. amarum (?x; 2n ~ 90). The aim of this thesis is to clearify the unknown evolutionary relationships between the taxa, between the annuals and perennials, diploids and polyploids. The following questions should be answered in this study: 1) What is the origin and distribution of the rediscovered diploid perennial taxon and what is its relationship to the other members of the group; 2) What is the distribution pattern of the perennial taxa of the genus Anthoxanthum in Europe and what is their haplotype differenciation (overall distribution of the taxa and haplotypes and the existence of their sympatric occurence); 3) What evolutionary ties exist among the species and what is the origin of allotetraploid taxon A. odoratum s.str. The...

A vast range of factors shape the genetic structure of plant populations. In this thesis, I focus on two of them. The first factor, polyploidization, is a process of chromosome set multiplication through whole-genome duplication within a single species (autopolyploids) or hybridization of two different species (allopolyploids). It rapidly brings changes into genomes, allowing species to occupy distinct niches, adapt to new habitats, colonize them, or adapt to changing environment in their native range. But it comes at a certain cost - difficulties in mitosis and meiosis, changes in cellular architecture. Furthermore, after cytotype establishment, new individuals have to deal with cytotype exclusion effect, competition with parental individuals and higher nutrition requirements. In this thesis, I present the effect of polyploidization on populations of three species- Arabidopsis arenosa, Aster amellus and Festuca rubra. The second factor changing the population genetic structure presented in this thesis is the fragmentation of populations. Population fragmentation can be caused by natural or anthropogenic activities and often leads to overall reduction in population size and reduced connectivity among fragments. Restricted gene flow may threaten long-term population survival due to inbreeding...

This thesis aimed on comparison of environmental requirements and morphological and biological traits of diploid and triploid cytotypes of wetland plant flowering rush (Butomus umbellatus), occurring in Eastern Slovak Lowland in unique mixed populations, and to develop primers for variable microsatellite loci suitable for further genetic studies. In total, 72 populations of Butomus umbellatus were found. The analysis of relative genome size by the flow cytometry (FCM) technique revealed 34 exclusively triploid cytotype populations, 8 exclusively diploid populations and 30 mixed populations of Butomus umbellatus. In mixed populations, the numbers of diploid and triploid individuals are quite equivalent and the plants create combined compact communities. Analyses of environmental characteristics of sites with specific cytotypes (PCA, RDA, ANOVA) revealed no difference in site requirements of diploid and triploid Butomus umbellatus plants. Morphometric analyses (PCA, CDA) of traits of 36 diploid and 54 triploid plants confirmed differing morphology of both cytotypes occurring in the nature. Subsequent replanting of these plants into pots and cultivation further increased these differences. The ratio of width and length of internal perianthium is the most reliable parameter to distinguish diploid and...

Contact zones of cytotypes harbour a unique opportunity to study the dynamics and evolution of mixed-ploidy systems. Butomus umbellatus (flowering rush) is one of a few species in which diploid and triploid cytotype is present in nature. The first known mixed-ploidy populations of B. umbellatus were discovered in south-eastern Slovakia during the previous studies. Common occurrence of the species in an area with substantially natural dynamics of wetland ecosystems represents a unique model system for unbiased comparisons of traits and genetic diversity between diploid and triploid individuals along with their dispersal capabilities on a landscape level. The main aim of of this thesis is to uncover the truth behind evolutionary processes that are taking place in the contact zone of diploid and triplioid cytotype of B. umbellatus in south-eastern Slovakia. Using flow cytometry and molecular methods (microsatellites) we will test whether this is a primary or secondary contact zone and assess the level of genetic variability between individuals and populations of both cytotypes. Using the analysis od microsatellite loci we discovered that the contact zone of cytotype is of both primary and secondary character and gene flow between cytotypes was also detected. These results were supported by high production and...

The presented study tries to reveal the evolutionary history of polyploid complex Galium pusillum aiming on a rare czech endemic species G. sudeticum, an ideal model to study allopatric speciation in the context of Central European (post)glacial development. The species G. sudeticum grows in Krkonose Mts. and on serpentines in western Bohemia (Slavkovský les) more than 200 kilometers away. Our morphological and molecular data suggest a clearly different history of its two isolated areas. The populations in Krkonose Mts. are probable relics of mountainous species G. anisophyllon which was there on its northern border of occurence and hybridized with lowland species G. valdepilosum during postglacial vegetations shifts. This fact is well supported by intermediate position of Krkonose Mts. populations in both morphological and molecular AFLP analyses and by sharing the same chloroplast haplotype with geographically close lowland populations. On the other hand the serpentine lowland populations in western Bohemia are both morphologicaly and genetically indistinguishable from G. valdepilosum. Distinct genetic lineage of few populations belonging to G. valdepilosum (incl. one traditionaly referred as G. sudeticum) was found in western Bohemia and Bavaria, located on relic stands (calcareous and serpentine...