|
|
Biosystematic revision of the Spergularia echinosperma complex
KÚR, Pavel
This thesis is focused on the biosystematic study of the Central-European endemic Spergularia echinosperma. With the combined use of morphometric analyses, genome size measurements and molecular tools, the taxonomic issues associated with this species have been clarified. The existence of S. kurkae, a stable allotetraploid hybrid between diploid S. echinosperma and tetraploid S. rubra, has been proven. Based on several lines of evidence, including distinct morphological separation and frequent occurrence in the absence of the parental species, treating S. kurkae as a separate species is proposed. In addition, two infraspecific taxa within S. echinospermaS. echinosperma subsp. echinosperma and S. echinosperma subsp. albensisdiffering in distributions and ecology have been described. A complete revision of the localities of S. echinosperma, S. kurkae and S. rubra in the Czech Republic is also presented. Furthermore, the development of 16 polymorphic microsatellite loci for S. echinosperma is reported.
|
|
|
Dispersal, distribution and genetic diversity of Melampyrum subalpinum group
CHLUMSKÝ, Jan
This thesis is focused on the dispersal, distribution, and genetic diversity of the taxonomically highly diverse Melampyrum subalpinum group. A complete revision of the localities of M. subalpinum in the Czech Republic and Slovakia is presented. The genetic variation and population structure of the M. subalpinum group across its distribution range is described based on allozymes, nuclear and chloroplast gene sequencing, and genome size. Signs of historical hybridization with M. nemorosum were found in some populations. A comparison of seed dispersal by ants between the co-occurring M. subalpinum and M. pratense and the influence of differences in this process are presented. A new mean of seed dispersal (endozoochory) is introduced for Melampyrum. Myrmecochorous dispersal distances are tested and Holocene migration possibilities are discussed taking into account endozoochory.
|
|
|
Alternative powertrains of vehicles
Filip, Vojtěch ; Kučera, Pavel (referee) ; Píštěk, Václav (advisor)
The aim of this thesis is the analysis of most common alternative drive systems currently used in cars, their comparison with the current gasoline and diesel engines. Familiarization with the technical solutions of drives, their categorization into several groups according to the specific key features. It also deals the most important components of an alternative fuels automobiles, respecting their strengths and also weaknesses that currently hinder expansion of these propulsions, economically as well as technically.
|
|
|
Modern hybrid drive of passenger vehicles
Švoma, Jan ; Blaťák, Ondřej (referee) ; Vančura, Jan (advisor)
This bachelor thesis deals with the current hybrid-drives in passenger cars. The thesis contains the categorization of hybrid systems according to structure and use. It also discusses the analysis of individual components and describes their suitability for use in different situations. It is focused on current offering of hybrid vehicles and development opportunities. At the end of are evaluated economic aspects and prospects for the use of these systems in the future.
|
|
|
Study of the reproductive biology of the crayfish - mating, laying eggs and morphological structure of the male and female gametes
KUBEC, Jan
In the nature, crayfish are represented like predators or a part of food base of some fish. Also in free waters they acts as detrivors and are an important element in the nutrient and energy circle in aquatic ecosystem. The crayfish weren't able to avoid negative impacts of anthropogenic activities such as water pollution and devastation of habitats. For these reasons reproduction of the crayfish is necessary in hatcheries and farms. The main aim of my work was to study the reproductive biology of the crayfish focused on the process of mating, the interval between mating and laying eggs, fertilization and morphological structure of the male and female gametes. Among the secondary objectives there was included using of repeated electrostimulation of the crayfish and the possibility of hybrids of the noble crayfish (Astacus astacus) and the narrow-clawed crayfish (Astacus leptodactylus). The observation of the period of reproduction was realized on representativies of the noble crayfish and the narrow-clawed crayfish throughout natural mating in the tanks. The structure of gametes was observed on the samples taken from thenoble crayfish (Astacus astacus), the narrow-clawed crayfish (Astacus leptodactylus), the signal crayfish (Pacifastacus leniusculus), the red swamp crayfish (Procambarus clarkii) and spinycheek crayfish (Orconectes limosus). The experiments were carried out during the autumn season in 2012 and 2013. The results of observations of the reproduction of crayfish made us clear as for the period and intervals for all phases of the process of mating crayfish. For females the noble crayfish and the narrow-clawed crayfish was found oviposition without the presence of males. Their individual components have been described by using ultrastructure of males and female gametes. Repeated electrostimulation showed at the family Astacidae as a suitable tool for collecting large mass of sperm material. Hybridization experiment proved that it can occur to mate the two species of crayfish in areas where they occur simultaneously. These experiments helped to further knowledge of reproductive biology of crayfish.
|
|
|
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.
|
|
| |
|
| |
|
|
Comparison of growth and survival of selected tench breeds in performance test
PRCHAL, Martin
This thesis is focused on comparison of performance traits of growth and survival of selected breeds of the common tench using the pure-blooded animal breeding method. The best way how to compare performance traits of particular breeds is through so-called performance tests. For this thesis following breeds were chosen: Vodňanské -(V), Hlubocké(H), Königswartha (German - N), Mariansko-Lázeňské (ML) and Romanian(R). The Golden tench were chosen as a control breed in order to correct the influence of the environment on the weight achieved. The testing began with selection and stripping preparation of spawners of relevant breeds selected for testing. Own performance test of selected groups proceeded from yolk - sac fry to the age of L2 in ponds with semi-intensive farming. Each tested breed was bred in the first growing period and in winter period together with the control group only. After group marking (the second growing period) by the cryogenic method, all breeds were bred together with triplication. In the first testing period reproductive parameters of spawners and their weight and survival of tested breeds were evaluated, in other period only weight and survival were evaluated. Reproductive parameters in males did not vary statistically in none of the parameters using any statistical method. In females significant differences were proved only between the breeds ?Hluboká? and the control breed. After the second growing period the highest weight was achieved by the Mariánsko-Lázeňské breed (112.9 ? 44.9 g), whose weight was statistically comparable only with German breed (105.4 ? 32.4 g). The survival after this period ranged from 70,4 % (Romanian breed) to 84,1% (Mariánsko-Lázeňské breed) and all breeds had statistically comparable values. The best performance traits after the second year of testing was achieved by the Mariánsko-Lázeňské breed.
|
|
| |
guest ::
