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Hybridization and microevolutionary relationships among Central European Diphasiastrum species
Dvořáková, Kristýna ; Urfus, Tomáš (advisor) ; Chrtek, Jindřich (referee)
Genus Diphasiastrum Holub is one of the most complicated and biosystematically very little investigated groups within Lycopodiaceae family. There are 6 species recognized in Central European region. Three of them (D. alpinum, D. complanatum, D. tristachyum) are considered basic - parental taxa, and their hybridization probably gave origin to the three adjacent species - intermediates (D. issleri, D. zeilleri, D. oellgaardii). These supposedly hybridogenous taxa often co-ocur with at least one parental species. All the taxa often meet in secondary habitats where they tend to form hybrid swarms (e.g. on ski slopes which represent an ideal biocorridor for meeting the species from alpine zone with the species from lower altitudes). In such places reciprocal crossings between all of the taxa occur, often accompanied by introgression. The degree of hybridization, including the possible introgression, was studied using absolute genome size analyses combined with classical and geometric multivariate morphometrics. Genome size was estimated for 570 plants from 83 localities, mostly from the Czech Republic. Despite the fact that each parental taxa had a specific range of absolute genome sizes, adjacent species formed more or less disconnected continuum. Multivariate statistical methods (PCA, RDA, Loess, PLS)...
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An assessment of interspecific hybridization between Central-European taxa from the genus Nymphaea: insights from flow cytometry and multivariate morphometrics
Kabátová, Klára ; Suda, Jan (advisor) ; Rybka, Vlastimil (referee)
Although the genus Nymphaea (waterlily) includes only two native species (N. alba and N. candida) in Central Europe, it poses a great challenge to taxonomy and biosystematics. The determination of both species is hampered by their phenotypic similarities, and species boundaries can be further blurred by interspecific hybridization. In addition, ornamental cultivars of different parentage often escape from cultivation and make the situation even more complex. To get insight into the caryological and phenotypic variability of czech waterlilies, the DNA flow cytometry and both distance-based and geometric morphometrics were used. Collections showed two different groups of fluorescence intensities, corresponding to N. alba and N. candida, respectively. In addition, intermediate values of nuclear DNA amount were found in some plants from South Bohemia, indicating their hybrid origin. Surprisingly, ornamental cultivars possessed the smallest genome sizes. The amount of nuclear DNA therefore seems to be a promising species-specific marker that enables not only native species but also cultivars to be distinguished. Cytometrically-proven individuals have been subjected to multivariate morphometrics, and high differenciation was discovered especially between native species. More complicated seems the distinction...
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Genetic diversity and evolutionary history of Czech endemic taxa from the genus Dianthus
Kalůsková, Jana ; Suda, Jan (advisor) ; Chrtek, Jindřich (referee)
Abstract This MSc. thesis deals with karyological, genetic and phenotypic variation of selected taxa from the genus Dianthus L. in the Czech Republic and adjacent countries. The evolutionary history of the genus has been shaped by several microevolutionary processes, including interspecific hybridization, genome duplication, and edaphic speciation. These processes led to the origin of a number of phenotypically similar taxa, which are often restricted to a narrow geographic area. One subendemic and three endemic taxa occur in the Czech Republic. These (sub)species were used as model groups to gain insight into microevolutionary processes in small populations and the postglacial development of the genus in Central Europe. The thesis consists of three parts, each addressing different evolutionary phenomenon: Dianthus arenarius subsp. bohemicus is a critically endangered endemic psammophyte currently known from a single population in Central Bohemia. The site is also inhabited by widespread D. carthusianorum. Interspecific hybridization has been suspected on the basis of morphological characters, but this has never been confirmed by any other technique. I exploited differences in the number of chromosomes between both species and, with the aid of DAPI flow cytometry, estimated relative DNA contents of...
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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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Morphological variability of species \kur{Euphrasia stricta} and \kur{Euphrasia nemorosa}
HOŘČICOVÁ, Šárka
Euphrasia L. belongs to the most taxonomically complicated genera in Europe. This is caused especially by considerable similarity of majority of species, intraspecific variation and hybridization, which occurs very often in this genus. A review of the studied genera and hybridization was worked up. Morphological variation of Euphrasia stricta, Euphrasia nemorosa and morphologically intermediate populations was investigated using conventional and geometric morphometric methods. Isolation and optimalization for PCR of ITS, matK and trnT-trnL regions has been made.
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