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Morphological differentiation and distribution of taxa in the Galium palustre group
Dohnalová, Pavla ; Kaplan, Zdeněk (advisor) ; Chrtek, Jindřich (referee)
This work is focused on the polyploid group of Galium palustre. The process of polyploidization has significantly influenced the evolution of angiosperms and in the studied group led to the emergence of 4 cytotypes known so far. Two of the cytotypes are found in the Czech Republic, diploid and octoploid, distinguished as species Galium palustre and Galium elongatum, respectively. Both taxa are mostly considered as species, which differ in quantitative characteristics, but these show considerable phenotypic plasticity. Therefore, the exact extent of morphological variation, precise distribution and ecology of the species are still unknown. The flow cytometry was used to distinguish cytotypes; it also showed variation in genome size and revealed a new dodecaploid cytotype in the Czech Republic. Subsequent morphometric analysis identified characteristics suitable for distinguishing the individual cytotypes. The most reliable are the length and width of a stem, the length of the leaf, the length of the longest branch, the number of leaves in whorls, the length of the inflorescence and the length of the mericarp. Based on these results, herbarium specimens from several herbaria were examined. The results also showed slightly different ecological preferences of cytotypes and their distribution in the...
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Differenciation in the Galium palustre group in central Europe
Dohnalová, Pavla ; Kaplan, Zdeněk (advisor) ; Knotek, Adam (referee)
The aim of this work is to summarize the current knowledge about the Galium palustre complex in Central Europe. It is a polyploid complex, which has involved polyploidization and hybridization in its evolution. Individual cytotypes somewhat differ in quantitative characters and in ecology and show considerable morphological variation. For this reason, the taxonomy of the group is unclear and the opinions on the cytotype classification differ. There are two species in the Galium palustre complex distinguished in the Czech Republic, the diploid Galium palustre and the octoploid Galium elongatum. Exact data regarding their distribution and morphological variation are not known and therefore this thesis will be followed by a master's thesis, where modern methods will be used to clarify the issue. Key words: polyploidization, hybridization, Galium palustre, Galium elongatum morphological variation
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