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Evaluation of cytotype and morphological variability and hybridization rate in water-milfoils (Myriophyllum) in the Czech Republic and adjacent territories
Hrdinová, Magdalena ; Trávníček, Pavel (advisor) ; Koutecký, Petr (referee)
Myriophyllum L. (watermilfoil) belongs to one of the most invasive genus of the Northern Hemisphere. The three most agressive species, one of which is native to Europe (M. spicatum), are widespread throughout the majority of United states and two of them (M. aquaticum and M. heterophyllum) are becoming invasive in several Europaean countries as well. Therefore, Europaean populations of both native and invasive species, represents ideal place where to study processes which account for watermilfoils' invasivness. In this study, flow cytometry, morphometric analyses and germination experiments were employed to evaluate cytotype and morphological variability of Myriophyllum along with its potential to hybridize and propagate generatively. Five ploidy levels were detected in Europe, however no ploidy variability has been found within any species except for M. sibiricum (hexaploids and nonaploids) and one population of M. aquaticum (hexaploids and oktoploids). Flow cytometry proved to be useful tool for purposes of distinguishing species of different ploidy level and their potential hybrids. Nevertheless, the key species - M. sibiricum and M. spicatum - among which probably even more aggressive hybrids were recently identified, have similar hexaploid level. Thus flow cytometry cannot facilitate...
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Application of next-generation sequencing for phylogenetic reconstruction of polyploid plants
Skopalíková, Jana ; Fér, Tomáš (advisor) ; Šrámková, Gabriela (referee)
This bachelor thesis summarizes available information about currently used next- generation sequencing (NGS) methods where a big progress was achieved during last few years. Great advantage of NGS is the ability to gain huge amount of data at much lower cost per base compared to the Sanger sequencing. However, there are various pitfalls in data analysis. Nowadays it is possible to sequence the entire genomes of individuals. Nevertheless, this approach remains challenging when studying many individuals, e.g. in phylogenetics. Recently, several approaches for effective reduction of genome complexity arose: transcriptome sequencing (RNA-Seq), target enrichment, restriction digest-based methods (RAD-Seq, RLL, GBS), genome skimming (shallow sequencing), etc. Each method has both advantages and disadvantages that affect its utility in phylogenetics. Furthermore, the thesis deals with polyploid speciation and particularity of phylogenetics in polyploid plants - selection of suitable markers followed by data processing and phylogenetic analyzes. The last part of the thesis is devoted to my future research of polyploid genus Curcuma L.
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Is there any influence of ecological gradient on the introgression and its evolutionary consequences in the genus Arabidopsis?
Hojka, Jakub ; Marhold, Karol (advisor) ; Mráz, Patrik (referee)
1 Hybridization, introgression and polyploidy, especially in their combination, belong to the most important speciation processes in vascular plants. Athough basic features of these processes are generally well known, their cases in particular groups of plants and concrete cases differ a lot and their studies often bring interesting results. In the genus Arabidopsis several cases of combined hybrid and polyploid speciation are known (e.g. A. kamchatica, A. suecica) and there are also cases where we expect introgressive hybridization (e.g. between A. arenosa and A. petraea). The aim of the bachelor thesis is an evaluation of known cases of homo- and heteroploid introgressive hybridization and hybrid speciation in the genus Arabidopsis in the context of similar cases in the family Brassicaceae and perhaps also other families of vascular plants. Next aim is to design method of detailed evaluation of the introgressive zone of A. arenosa and A. petraea (= A. lyrata subsp. petraea) in Central Europe using mophological, cytometric and molecular evidence as well as ecological parameters of studied localities. Set of morphological characters will be tested on the currently available material of A. arenosa that is cultivated at CEITEC Brno as part of the finalised GACR project.
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Diversity and ecology of filamentous green conjugate algae
Strouhalová, Pavla ; Šťastný, Jan (advisor) ; Pichrtová, Martina (referee)
Filamentous conjugating algae have a cosmopolitan distribution. They often inhabit fragile freshwater habitats such as temporary hydrated ditches or puddles of melting snow. Occurrence in this environment entails having to deal with extreme conditions. That helps them to variously adaptation and also the formation of resistant stages. Algae belonging to this group have an important role in nature, because they are often the first species that inhabit newly created habitats and consequently also often become the dominant species. Diversity, as well as the ecological requirements of individual representatives, is unclear. Taxonomy of filamentous algae is conjugating is most based on morphological characters that are not very reliable. For filamentous conjugating algae is polyploidy really frequent. With changeable ploidy relate also morphological variability and different environmental requirements.
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Variation of the species Urtica dioica in Central Europe
Rejlová, Ludmila ; Urfus, Tomáš (advisor) ; Mandák, Bohumil (referee)
Although the European flora belongs to the best explored at the global scale, still there are several largely neglected plant groups, which may surprise by marked variation. One of these groups is Urtica dioica s. l., consisting of vaguely described taxa (microspecies / subspecies) with indefinite distribution. The most important source of variation in U. dioica s. l. is probably polyploidy (2x, 4x; x = 13). The complex comprises an ubiquitous tetraploid cytotype (U. dioica s. str.) and several obscurely defined relict 2x taxa. The cytogeographical analysis through Europe (770 populations / over 3 200 individuals) revealed marked distribution pattern of U. dioica s. l. cytotypes. We identified 106 diploid populations (13%) and 633 (82%) tetraploid populations. For the first time we detected triploid and pentaploid level (from mixed populations). Prevailing tetraploid U. dioica s. str. is predominantly synanthropic, whereas diploid taxa strictly occur in primary and relict habitats (primarily alluvial forests, tundra, Mediterranean mountains). The analysis of the absolute genome size of individuals from U. dioica clade and other closely related taxa showed different values of 2x U. kioviensis (19 % higher than 2x U. d. subsp. subinermis) and 2x U. bianorii (33% higher than 2x U. d. subsp....
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Polyploidy in natural populations of Arabidopsis
Bayerová, Jana ; Kolář, Filip (advisor) ; Čertner, Martin (referee)
This thesis deals with polyploidy in natural populations in the genus Arabidopsis. It summarizes information about the relatives of Arabidopsis thaliana, a prominent model organism for research on genetics and plant physiology. Literature shows that polyploidy affects ecological, climate and soil requirements, as well as mating system of the plants in genus Arabidopsis. Most of the published studies is focused on the study of artificial polyploid hybrids created by crossing experiments - especially with the Arabidopsis thaliana. In contrast, my thesis deals with the natural polyploids observed within the genus. In particular, I focus on the nearly unstudied di- polyploid complex of high-altitude populations of Arabidopsis arenosa in the Tatra Mountains. This complex represents a unique model system for studying the effects of polyploidization in the wild - thanks to the high morphological and ecological diversity of the hybrids, and to the relative genetic similarity of the parental populations. Key words: allopolyploid, Arabidopsis, Arabidopsis arenosa, autopolyploid, hybridization, polyploidization, Tatry
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Ecological and evolutionary consequences of edaphic differentiation in plant polyploid systems
Kolář, Filip ; Suda, Jan (advisor) ; Tribsch, Andreas (referee) ; Krahulec, František (referee)
The thesis deals with evolutionary and ecological consequences of edaphic speciation (adaptation to different soil types) and genome duplication (polyploidization), acting in concert. Using a wide range of ecological, karyological and molecular approaches, several hypotheses of general importance have been examined in three model angiosperm systems (ploidy variable species or species aggregates occurring both on and off specific substrates, including serpentines and calcareous soils). In the Knautia arvensis group (Caprifoliaceae) a unique cryptic diploid lineage in central Europe was identified to be restricted to serpentine and limestone outcrops, which served as refugia during environmental changes (forest spread, human impact) in the Holocene. These refugial populations exhibited strong evolutionary potential because they were able to polyploidize and escape beyond the borders of their original edaphically-conditioned refugia owing to hybridization with surrounding widespread homoploid genotypes. Survival of both Knautia cytotypes on serpentine soils was facilitated by their high tolerance to chemical stress factors such as high Ni concentrations and low Ca/Mg ratios. In the Galium pusillum group (Rubiaceae), a striking cytological, ecological, and taxonomic, diversity was revealed in northern and...
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Risk assessment of interspecific hybridization between endemic Campanula bohemica and widespread C. rotundifolia s.l.
Hanušová, Kateřina ; Suda, Jan (advisor) ; Krahulec, František (referee)
The thesis deals with phenotypic, ploidy and genetic variation of two Campanula species occurring in the Krkonoše Mts., namely the endemic C. bohemica and widespread C. rotundifolia subsp. rotundifolia. For comparative purposes subspecies sudetica of the latter species was also included. The main aim was to get insight into population structure and assess the threat of interspecific hybridization to the survival of the endemic bluebell. Flow cytometry, distance-based morphometrics and molecular analysis were used to address these questions. Three distinct groups of fluorescence intensities were revealed by flow cytometry, corresponding to DNA diploids, tetraploids and pentaploids. While diploids morphologically matched the nominate subspecies of C. rotundifolia, tetraploids corresponded either to C. rotundifolia subsp. sudetica or C. bohemica. Most populations from the Krkonoše Mts. were uniform although a sympatric growth of diploids and tetraploids was encountered in 12 populations. Only two pentaploids individuals, most likely of hybrid origin, were found, which indicated that interspecific hybridization is much less common than previously assumed. The two tetraploid taxa were distinguished by molecular markers. A combination of flow cytometry and molecular analyses thus allowed reliable...
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