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Genome size studies in plants - from intraspecific variation to ecological consequences
Lučanová, Magdalena ; Trávníček, Pavel (advisor) ; Leitch, Ilia (referee) ; Šmarda, Petr (referee)
Nuclear DNA content (genome size) is one of the basic characteristics of living organisms. In the Angiosperms, the range of genome size is 2,300-fold, which raises questions about the causes and consequences of this tremendous variation. This thesis deals with genome size in plants from the level of intraspecific homoploid variation, through intraspecific ploidy variation, to interspecies comparisons. On various study systems we investigated the dynamics and ranges of genome size variation, tried to reveal possible associations between genome size and selected biological traits, and assessed the extent to which differences in genome size are manifested at the ecological and evolutionary level. As a means of estimating genome size we applied flow cytometry (FCM). In Taraxacum stenocephalum we conducted a detailed study of its enormous genome size variation. We carried out crossings of parents with various genome sizes and compared these parental genome sizes with those of F1 offspring. We also attempted to reveal the association of genome size with various growth traits. In Galium valdepilosum and Arabidopsis arenosa we carried out an extensive flow-cytometric ploidy level screening and compared the distribution and ecological preferences of detected cytotypes. We studied the Andean genus...
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Genome size evolution in tropical tribe Globba (Zingiberaceae)
Pospíšilová, Monika ; Fér, Tomáš (advisor) ; Zedek, František (referee)
The variability of the genome size reaches several grades even within relatively close groups of plants. The study of the genome size in the phylogenetic context provides interesting results which characterize the evolution of the individual groups of plants. In this respect, tropical plants have yet not been studied. Tropical genus Globba (ca. 100 species) belongs to an economically significant family Zingiberaceae. The diversity centre is found in Thailand but it spreads from east India and southern China up to Indonesia and the Philippines. It is a polyploid complex which exists in two cytotypes within one genus (2n = 32 a 2n = 48); it is characteristic minimally in three out of seven distinguished sections. The aim of this thesis has been a reconstruction of the group phylogeny, discovering the role of the polyploid and evaluation of the genome size evolution of the Globba genus in the phylogenetic context. To this end, modern biosystematic methods were used (flow cytometry, chromosome counting, sequencing of the nuclear and chloroplast DNA regions). Many types of software and statistical methods were used to process and interpret the data. In this group, the genome size was measured for the first time. Out of 87 individuals, the smallest size was measured with Globba nuda (2C = 1.11 pg). The...
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Genome size evolution in the Zingiberaceae
Pospíšilová, Monika ; Fér, Tomáš (advisor) ; Kolář, Filip (referee)
The purpose of this study is to evaluate the existing knowledge on the evolution of genome size and also to focus on genome in the phylogenetic context. Among angiosperms we find a wide range of C-values (1C = 0.63 pg ? 1C = 127.4 pg), but the modal value is 0.6 pg. We still do not know much about the nature and mechanisms of plant genome size evolution, but we are learning more and more every year. There are already dozens of studies dealing with the dynamics of genome size of smaller taxonomic groups and on four of these they demonstrate possible approaches. Researching within higher taxonomic groups such as families is difficult and so more valuable. New research on the evolution of genome size in the family Zingiberaceae has started and my master thesis dealing with the Globbeae tribe should be part of it.
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Phenotypic plasticity and cytotypes of \kur{Agrostis stolonifera} in the Czech Republic
KUBEŠOVÁ, Magdalena
Presence and range of phenotypic plasticity in the Agrostis stolonifera polyploid complex (Poaceae) was studied in the territory of the Czech Republic. Plants were cultivated under different experimental conditions. Stomatal size of different Agrostis stolonifera cytotypes was measured. Flow cytometry was applied for genome size estimation. Ploidy levels were determined for more than 150 samples of Agrostis stolonifera as well as several specimens of Agrostis canina, A. capillaris, A. gigantea, A. rupestris and A. vinealis. Absolute DNA content was estimated in all studied species. Isozyme analysis was used to test the possibility of the hybrid origin of pentaploid individuals of Agrostis stolonifera species.
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