National Repository of Grey Literature 7 records found  Search took 0.00 seconds. 
Evolution of members of the genus Cardamine from the Anatolia-Caucasus region and the Balkan Peninsula
Kantor, Adam ; Slovák, Marek (advisor) ; Frajman, Božo (referee) ; Tribsch, Andreas (referee) ; Oberprieler, Christoph (referee)
This thesis aims to elucidate evolution of the members of the selected species groups of the genus Cardamine, which is a species-rich genus with cosmopolitan distribution and very complex evolutionary history. The studied species were represented by hygrophytic perennials, with the focus laid on their diversity in the Balkan Peninsula and Southwestern Asia, with the emphasis put on the Anatolica-Caucasus region. These regions harbour global biodiversity hotspots and important glacial refugia, yet, they have been largely understudied in terms of knowledge of evolutionary mechanisms and environmental factors that have played there a role of plants diversification and speciation drivers. In this thesis, questions concerning the phylogeny and taxonomy of the studied groups were addressed, with aim to determine the role of polyploidy and hybridization in their evolution. Hyb-Seq was the majorly applied method, representing a technique based on next-generation sequencing, which has proven to be a very efficient and versatile method for resolving evolutionary questions. An integrative approach was employed, combining Hyb-Seq with a variety of other karyological, molecular, cytogenetic and ecological niche modelling methods, which provided a very complex insight into the addressed topics. This thesis...
Population structure and evolutionary history of Central European bellflowers from the Campanula rotundifolia agg.
Šemberová, Kristýna ; Schmickl, Roswitha Elisabeth (advisor) ; Tribsch, Andreas (referee) ; Štech, Milan (referee)
6 Abstract For understanding extant species diversity, knowledge about processes acting at the population level is crucial. Besides mutations generating de novo genetic variation, three major processes, i.e., polyploidy, hybridization and local adaptation, notably impact population structure and cause evolutionary novelty. Campanula rotundifolia agg. was chosen as a model group for the joint study of these processes because it represents a polyploid complex with three major cytotypes (2x, 4x, 6x), a hitherto unknown ability to hybridize, and a pleiad of putative species that have undergone local adaptation to different conditions. In particular, polyploidization in the complex is acknowledged for generating morphological variation, facilitating long-distance dispersal and shifts in the environmental niche. It also creates a reproductive barrier, thus enabling sympatric speciation. Prerequisites for local adaptation are morphological variation and strong selection pressures leading to adaptive divergence and the rise of many endemic taxa, mainly at the extremes of environmental gradients. On the other hand, for locally adapted or endemic taxa, hybridization with a widespread taxon is one of the main existential threats. Here, I focused on C. rotundifolia agg. populations in Central Europe its hypothetical...
Study of plant dispersal in river corridors using molecular marker
Fér, Tomáš ; Herben, Tomáš (advisor) ; Chrtek, Jindřich (referee) ; Tribsch, Andreas (referee)
5 Summary The thesis presents how the use of molecular markers (AFLPs and microsatellites) can help when studying plant dispersal in river systems. Analysis and interpretation of the spatial pattern of genetic variation allowed to address and discuss following aspects of long-distance dispersal in these linearly structured systems: (1) the extent of long-distance dispersal, (2) the intensity of vegetative long-distance dispersal, (3) unidirectional transport along the streams, and (4) dispersal among rivers. The first part of the PhD. thesis presents several general aspects of plant dispersal, methodological approaches used to detect dispersal, and possibilities of analysis and interpretation of the molecular data. It also gives a short introduction to the methodology used in the particular studies, summarizes the results of all studies, and discusses how differences detected by molecular markers correspond to dispersal possibility (e.g., by water, by wind) of the selected species. The second part contains a set of four papers, each focusing on a detailed survey of dispersal possibilities of one of four plant species within the river system of the Cidlina, the Mrlina and partly also the Labe Rivers (Czech Republic). Above- mentioned aspects of dispersal in river systems are further discussed in the light...
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...
Biology, ecology and invasion characteristics of Campylopus introflexus in the Czech Republic
Mikulášková, Eva ; Soldán, Zdeněk (advisor) ; Tribsch, Andreas (referee) ; Kučera, Jan (referee)
A B S T R A C T Ecological and economic impact of invasive plants to natural ecosystems is the subject of many studies; however, invasive bryophytes have been stud- ied only marginally. Campylopus introflexus (Hedw.) Brid. is one of the most strongly invasive bryophyte species in Europe. The species appears to be native in the Southern Hemisphere. In Europe, it was collected for the first time in the British Isles in 1941. The moss has expanded eastward and the first collection in the Czech Republic is dated to 1988. This thesis found that more than 70 localities were known known in the Czech Republic in 2006, and more than 100 localities became known by 2011. It has been further demonstrated that the Czech Republic was colonized repeatedly by generative spores and all populations have a unique genetic composition. Genetic variation of the populations is low, the genetic diver- sity of populations within the Czech Republic is not correlated with their geographic position or with any of the monitored environmental variables. At a fine scale within particular localities, the species disperses by vege- tative diaspores, while it uses generative spores for spreading over longer distances. In Central Europe, C. introflexus prefers open coniferous forests, especially plantations of either spruce or pine. It colonizes...

Interested in being notified about new results for this query?
Subscribe to the RSS feed.