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Hybridization as a source of threat to Urtica kioviensis
Pekařová, Michaela ; Urfus, Tomáš (advisor) ; Štěpánek, Jan (referee)
Hybridization can have a negative impact on native taxa, which means a risk to plant biodiversity. Urtica kioviensis (2x) is a rare species of that grows in mixed populations together with two cytotypes (2x and 4x) of the closely related taxon Urtica dioica (stinging nettle). The presence of hybrids has been described in the past. Here I studied hybridization at localities in the Czech Republic (PR Plačkův les a říčka Šatava, NPR Ranšpurk), Slovakia (PR Jurský Šúr), and Hungary (Kóny, Fehér-tó). These taxa and their hybrids were studied by flow cytometry and morphometric analysis. Both methods provided evidence of ongoing hybridization. The continuous pattern at the diploid level suggests homoploid hybridization and subsequent introgression affecting mainly U. kioviensis. The possibility of backcrossing at the diploid level was also confirmed by analyses of pollen fertility or staining. Triploid individuals were also detected, showing differences in relative genome sizes and different positions relative to the parental taxa in morphometric analyses. Based on these results, it's not possible to reliably determine their origin. Heteroploid hybridization is likely to occur, but its presence cannot be definitely confirmed or excluded. Hybrids are common in mixed populations of U. kioviensis and mean a...
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Sezónní proměnlivost druhů \kur{Euphrasia stricta} a \kur{Euphrasia nemorosa} na Šumavě a v Předšumaví
BOČKOVÁ, Pavla
Euphrasia is a taxonomically complicated genus of hemiparasitic plants. It is able to form morphologically different aestival and autumnal types. In this thesis new type of aestival plants recently found in Šumava Mts was studied and compared with geographically close populations of E. stricta and E. nemorosa. Seasonal variation of these two species and aestival type and differences between populations of E. stricta from Šumava Mts and from its foothill were also studied.
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Morphometric and genetic analysis of group \kur{Centaurea macroptilon}
OTISKOVÁ, Veronika
Centaurea macroptilon group includes taxa Centaurea macroptilon, Centaurea oxylepis, Centaurea indurata and hybrids. In this master thesis we compared morphological and genetic variation among taxa of this group. Based on the results of morphometric and molecular analyzes we re-considered current taxonomic concept of studied species and suggested changes.
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Taxonomic study of the Eurasian taxa of Tortula muralis (Pottiaceae, Musci) complex
KOŠNAR, Jiří
The thesis aims at clarifying the taxonomic difficulties in the Tortula muralis complex. For the first time, the group was studied by means of morphometric analysis, ploidy level assessment by flow cytometry, and molecular analysis based on sequencing of ITS region of nuclear ribosomal DNA. Morphometric and cytometric studies found only two well distinguished groups within the complex. These groups corresponded to the markedly variable species T. muralis and to the rather uniform species T. lingulata. Variability in ITS sequences suggested extensive gene flow among some of traditional morphologically defined taxa of the complex. Multiple polytopic autopolyploid origin of polyploids was revealed in some taxa. Changes in taxonomic conception of T. muralis complex were proposed in order to reflect structure of morphological, karyological, and DNA variability in the group. Natural hybridization is probably an important evolutionary mechanism that generated morphological diversity and taxonomic complexity in the mosses of T. muralis complex.
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Morphometric analysis of viviparous lizard (Zootoca vivipara) in the Czech republic
KREJČÍ, Tomáš
Zootoca vivipara is the smallest of four species of lizard occurring in the Czech Republic. For many species of lizards sexual dimorphism was found in different characters and their presence was predicted also in this species. Eight characters were measured: total body length, snout {--} vent length, tail length, head length, head width, number of ventral scales, number of femoral pores and number of lamellae under the fourth finger of hind leg. Analyzed specimens from collections of Prague National Museum came from two areas {--} Šumava and Děčínský Sněžník. Analysis of covariance (ANCOVA) for the Šumava area showed sexual dimorphism: males were larger in total body length, in tail length, in head length, in head width and had higher number of femoral pores than females. Females had higher number of ventral scales than males. Analysis of covariance for the Děčínský Sněžník area showed sexual dimorphism in total body length, in tail length, in head length and in head width. All these characters were higher in males. Females had higher number of ventral scales. Variability of some characters showed dependence on altitude. Significant dependence on altitude investigated by analysis of covariance was detected in specimens from the Šumava area in total body length, in tail length and head length: the values of all these characters decreased with increasing altitude. Head width exhibited significant dependence on altitude only in absolute values (ANOVA): the values decreased with increasing altitude. Specimens from the Děčínský Sněžník area exhibited significant dependence on altitude only in absolute values of body length, of head length and of head width. Analysis of covariance was not significant.
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