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Population genetic aspects of plant invasions: studies of genetic and cytotype variability in invasive and native populations of \kur{Phalaris arundinacea} L. a \kur{Myriophyllum} sp.
KÁVOVÁ, Tereza
One of the hypotheses about the causes of invasive transmission of Phalaris arundinacea in the US is, that this species have repeatively introducted from Europe or by hybridization of the introduced genotypes with the native species. This is the same situation as Phragmites australis. Part of this intercontinental gene flow is enhanced by the production of Phalaris cultivars in Minnesota. The consequences of these exchanges have a significant impact on the management of invasive crops from both continents. Previous studies confirm only minimal morphological heterogeneity between cultivated and native (wild) forms of Phalaris arundinacea. In Phalaris arundinacea, we analyzed genetic similarities and differences between the US populations (Minnesota) and population of the Czech Republic. The extent of genetic variation in native and invasive populations was compared using ISSR markers. The occurence of commercial genotypes was observed across the full spectrum of invasive genotypes, which suggests a relatively frequent exchange of genes among forage, ornamental, and native US populations. The genus Myriophyllum is mainly significant because of its invasive species, which have always been in a special position as the course of ecological and evolutionary changes may be observed in real time. In Central Europe it is represented by three native species (M. spicatum L., M. alterniflorum and M. verticillatum) and two non-native species of North American M. heterophyllum and South American M. aquaticum. Species M. spicatum, together with M. heterophyllum and M. aquaticum, is one of the most important invasive plants that, due to their aggressive growth, cause many problems, especially in North America. The main theme of this Ph.D. is the evaluation of the role of polyploidization in processes leading to invasive character of some species of the genus Myriophyllum in the USA, cytological and population-genetic comparison of native (Eurasia) and invasive populations (US) of Myriophyllum spicatum. Moreover, possible "Pools" of genetic and cytotype variability of invasive populations and evaluation of usability of simple genome size were determinated in taxonomic determination by classical morphological procedure of unclassifiable plants, which might reduce the cost and efficiency of invasive stool biomonitoring and thus the management of its invasive populations
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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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