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Population cytotype structure and phenotypic variation of Campanula moravica
Šemberová, Kristýna ; Suda, Jan (advisor) ; Mráz, Patrik (referee)
Polyploidisation plays a major role in plant evolution. It can also cause taxonomic complexities as morphological differences are often blurred in higher ploidy levels. One of the taxonomically-intrigued groups of Central Europe is C. rotundifolia agg. Three ploidy- heterogeneous species are traditionally recognized in the Czech Republic: C. gentilis (2x, 4x), C. rotundifolia (2x, 4x) and C. moravica (4x, 6x). The thesis examines karyological and phenotypic variation of C. moravica, in the centre of its distribution (the Czech Republic and Slovakia). With the aid of modern biosystematics tools (DNA flow cytometry, multivariate morphometrics), marked discrepancies were revealed between published data and actual cytotype distribution pattern and morphological variation. In contrast to literature records, cytotype distribution in C. moravica is largely parapatric, with hexaploids occurring in Pannonian basin and tetraploids in Central and Eastern Slovakia. The type population of presumed tetraploids turned out to be hexaploid. The coexistence of one majority (4x) and six minority cytotypes (2x, 3x, 5x, 6x, 8x, 9x) was found in one population in central Slovakia and represent the most salient case of ploidy coexistence ever reported. Multivariate morphometrics showed that species identification on the...
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An ecological perspective on diatom morphology.
Fialová, Markéta ; Kulichová, Jana (advisor) ; Hodač, Ladislav (referee)
A traditional species concept of diatoms is based on morphological characters of their siliceous boxes. A multidisciplinary approach to defining species of diatoms has revealed the hidden diversity within the traditionally defined species. But the newly recognized species are morphological variable and indistinguishable by the naked eye. Recent studies showed that different morphotypes show different ecological preferences. This master thesis focuses on the morphology of natural populations of the diatom species complex Frustulia rhomboides which contains both the traditional and the cryptic species, and it engages how the morphology reflects the effects of environmental conditions. Landmark methods of geometric morphometrics were used in order to analyze the morphological variability of diatom frustules of this species complex within various peat bog habitats in the Czech Republic. Selected environmental parameters were measured and the species composition of diatom communities present in the samples was investigated. These data were used to analyze the relationship between the environmental conditions and the cell shape variability within the complex. The analysis revealed the main trends of morphological variability related to different environmental conditions. Two morphotypes characteristic...
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Population differentiation of Ochrophytes
Mensová, Anna ; Jurdíková, Katarína (advisor) ; Kulichová, Jana (referee)
This bachelor thesis deals with a differentiation of populations of Ochrophytes (photosynthetic Stramenopiles). Natural populations can differ in many aspects and their differentiation is observed on several levels. Ecophysiological and morphological differences are very often caused by phenotypic plasticity, which is a flexible answer to changing conditions of habitats. Genetic differentiation could express an adaptation to the local environmental conditions. The adaptation and a long-term isolation of populations are considered to be the leading factors in genetic differentiation. The other factors contributing to genetic differentiation are random evolutionary events such as founder effect or genetic drift. Detailed studies of populations lead to uncover the factors that cause the differentiation of populations as well as they contribute to the understanding of speciation mechanisms. The thesis compiled the information about different types of variability among populations within the classes of Ochrophytes.
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Risk of hybridization of threatened P. fruticosa with cultivated Prunus species
Musilová, Lenka ; Vít, Petr (advisor) ; Zahradníček, Jaroslav (referee)
Many agriculturally important fruit trees occur in the genus Prunus, among other also Sour cherry (Prunus cerasus) and Sweet cherry (Prunus avium). P. cerasus is considered to be an allopolyploid hybrid originated by hybridization of Prunus fruticosa (2n = 4x = 32) and P. avium (2n = 2x = 16). The world production of sour cherry fruit (P. cerasus) in 2008 is estimated to be more than 1, 15 million tones. Prunus fruticosa is a steppe (forest steppe) relict species, severely endangered in the Czech Republic (C2). The main threat of P. fruticosa are both the direct and indirect human activities, causing, above all the loss of natural biotopes and hybridization with cultivated species that ran wild to the nature. P. fruticosa hybridizes all over its occurrence area with wild P. cerasus (Sour cherry; which is not primary species of the Czech Republic) and originates fertile hybrid Prunus × eminens. The results of existing studies indicate that the hybrids are more common in the central Europe and that the frequency of hybridization rises towards the west. Such phenomenon is related to human activities (cherries cultivation and landscape changes). Many authors consider hybridization to be the main cause of endangerment of this species and noticed that in many habitats the hybrids could totally replace...
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Genetic basis of phenotypic variability in domesticated animals
Majerová, Veronika ; Komárek, Stanislav (referee) ; Reifová, Radka (advisor)
Understanding the mechanisms responsible for the origin of morphological variability among different species of animals represents an important goal in evolutionary biology. Origin and changes of the phenotypic variability during the evolution is possible to study in domesticated animals. The domesticated species of animals represent a brilliant model for studying the molecular mechanisms responsible for origin of new phenotypes due to enormous morphological variability of different domesticated breeds, effortless breeding in captivity and frequent knowledge of the genomic sequence. The aim of this bachelor work is to summarize actual findings about concrete mutations which are responsible for the origination of the new morphological characters in the domesticated animals. These findings can help us to clarify how the evolution functions on the molecular level.
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Biosystematic studies in the family Cyperaceae
KOŠNAR, Jan
The thesis was focused on the microevolutionary mechanisms that contribute to morphological diversity in selected members of the sedge family (Cyperaceae). Natural hybridization, evidenced from both morphological characters and molecular markers, was revealed to be a potentially important source of diversification in the tropical spikerushes of Eleocharis subgenus Limnochloa. High levels of phenotypic plasticity of clonal growth but rare genetic (ecotypic) differentiation among contrasting morphotypes were found in the polymorphic species Carex nigra, which implied that taxonomic splitting of the species was unreasonable.
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Morphologic plasticity of \kur{Centaurea jacea.}
KARÁSEK, Jakub
Morphological plasticity of brown knapweed (Centaurea jacea L.) was examined. South bohemian populations of subsp. jacea were compared to plasticity in larger area. The plasticity of local population overlaps with both subspecies. The correlation between abiotical factors and determination characteristics were found. Molecular survey using ISSR method shows no difference between subspecies. The final resolution of subspecies existence will be questioned in following study.
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Morphological and genetic variation in populations of Gymnadenia conopsea agg.
KOLOUŠKOVÁ, Pavla
The complex Gymnadenia conopsea s.l. represents a very problematic group in terms of taxonomy, showing a wide morphological, phenological, genetical and cytogenetical variability. The aggregate G. conopsea encompasses a range of taxa, two of which, G. conopsea (L.) R. Br. s.s. and G. densiflora (Wahlenb.) A. Dietr., have been acknowledged as beeing a species level. Individual taxa cannot be safely distinguished on the basis of morphological characteristics in all cases. Recently, there has been a lot of discussion concerning the taxonomical value of taxons within the G. conopsea complex. The complex is represented by a variety of cytotypes, while the major tetraploid cytotypes represent the above mentioned G. conopsea and G. densiflora taxa, that are easily distinguishable by means of flow cytometry. The taxonomical classification of minority cytotypes is not clear. For these reasons, to be able to obtain more detailed information, an application of different approaches from the field of morphology, cytogenetics and molecular genetics is suitable when evaluating the populations. In this thesis, morphological characteristics, AFLP and an analysis of microsatellites along with a measurement of ploid level using FCM have been used for evaluation. On the basis of evaluating a multidimensional cluster analysis and a dendrogram created by the UPGMA method combining these data, a specific dissimilarity of the G. densiflora and G. conopsea taxon has been confirmed. Based on the comparative analysis of microsatellite loci and overlapping morphometric characteristics of tetraploid and octoploid G. conopsea cytotype it can be assumed that the octoploid cytotype is a separate chromosomal aberration of tetraploid plants.
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Phenotypic plasticity and cytotypes of \kur{Agrostis stolonifera} in the Czech Republic
KUBEŠOVÁ, Magdalena
Presence and range of phenotypic plasticity in the Agrostis stolonifera polyploid complex (Poaceae) was studied in the territory of the Czech Republic. Plants were cultivated under different experimental conditions. Stomatal size of different Agrostis stolonifera cytotypes was measured. Flow cytometry was applied for genome size estimation. Ploidy levels were determined for more than 150 samples of Agrostis stolonifera as well as several specimens of Agrostis canina, A. capillaris, A. gigantea, A. rupestris and A. vinealis. Absolute DNA content was estimated in all studied species. Isozyme analysis was used to test the possibility of the hybrid origin of pentaploid individuals of Agrostis stolonifera species.
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