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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.
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Využití transgenních linií ječmene SCLW-GP-PHYA ve šlechtění
Hanáková, Marie
The F1 generation, which was obtained by hybridization transgenic lines of malting barley SCLW-GP-PHYA with feed barley of varieties Azit, Heris and Tocada, was formed for the purpose of transmission of the phyA transgene, which controls the production of the enzyme phytase. 107 hybrids of F1 generation, where it feed variety Azit was used as male plants, has been verified hybrid origin using SSR EBmac0603. In 27 individuals have been confirmed hybrid origin and by 23 individuals has been showed by the method PCR of the phyA transgene. Based on the measurement of phytase activity in the caryopsis F1 generation, which was lower compared with the female transgenic lines, but higher than in male feed variety Azit. F2 generation was observed phenotypic cleavage in size plant, length spike and grain size. Positive plants of the phyA transgene have been used to stabilize transgene and obtained homozygous plants by method androgenesis. From 4834 anthers have been obtained 54 green plants and 148 albinotic plants The phyA transgene were by the method PCR in 33 green plants (61.6 %) and 2 albinotic plants (1.4 %). Flow cytometry has been used to determine to level of ploidy in 54 green plants and have been 42 doubled haploid (77.7 %), 6 haploid (11.1 %), 4 tetrahaploid (7.4 %) and 2 trihaploid (3.7 %). Reciprocal hybridization has been performed, when feed varieties were used as female plants and transgenic barley lines SCLW-GP-PHYA as a male plants. By 10 plants od F1 generation were by the method PCR the transgene phyA in 8 plants.
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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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