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What is the reraction of plant saccharide status to enhanced CO2 concentration in the atmosphere?
Bardoňová, Radka ; Lipavská, Helena (advisor) ; Lhotáková, Zuzana (referee)
During last 200 years, the concentration of carbon dioxide (CO2), one of the most important greenhouse gasses, has significantly increased. It is assumed, that by the end of this century, the concentration of CO2 will be as much as two times higher than nowadays. The changes in atmospheric concentration of CO2 are largely caused by human activity. Both direct and indirect effects of CO2 lead to changes on every level of plant body, from changes in gene expression, through changes in physiology and anatomy, to whole-plant morphology changes. Understanding of these changes and relationships between them is necessary for our conception of future 'greenhouse' world and preparation for the life in it. Growth under elevated CO2 conditions generally leads to increase of the assimilation rate. The increase in the amount of fixed carbon then usually causes an increase in carbon to nitrogen ratio and changes in carbohydrate levels in plants. A common phenomenon related to growth at elevated CO2 concentration is an excessive accumulation of nonstructural carbohydrates in leaves. This accumulation can be associated with down-regulation of photosynthesis. However, changes in carbohydrate levels can occur in other plant parts. This Bachelor thesis is focused mostly on woody species. As perennials with secondary...
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Characterization of changes induced by Schizosaccharomyces pombe cdc25 gene related to earlier flowering onset
Čiháková, Klára ; Lipavská, Helena (advisor) ; Tylová, Edita (referee)
The study is focused mainly on mechanisms related to flowering acceleration in plants expressing cdc25 from Schizosaccharomyces pombe (Spcdc25 plants). In yeast, the gene in question codes a phosphatase responsible for activatory dephosphorylation at mitosis entry. In higher plants, however, the ortholog has not been identified yet. Some doubts even exist on the importance of this activatory dephosphorylation, though dephosphorylation itself has been documented in plants. Previous studies of our team revealed many differences in Spcdc25 tobacco plants; majority of them can be induced in WT by cytokinin application and thus, the hypothesis of cytokinin-like effect of Spcdc25 expression have been proposed. As the earlier flowering was one of the most pronounced effects, the aim of this study has been to characterize mechanisms, responsible for this phenomenon. The analyses of phloem exudates revealed weak tendency to lower saccharide transport to the apex in transformants. The sacharide content in the apex, however, was similar or slightly higher with significantly higher glucose proportion in transformants. Thus, a role of saccharides in flowering regulation should not be excluded. The analysis of the flowering-inducing genes expression has shown the only change: the expression of the tobacco homologue of...
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Does the synthesis of sugar alcohols represent a general mechanism of plant stress response?
Peldřimovská, Jitka ; Lipavská, Helena (advisor) ; Zelenková, Sylva (referee)
Plants cope with adverse environmental conditions with broad variety of defence mechanisms. One of them is the accumulation of compatible solutes, e.g. carbohydrates including sugar alcohols. The compatible solutes are involved in osmotic adjustment, scavenging of reactive oxygen species and they can protect macromolecules and cell membranes by simulation of water envelopes. The sugar alcohols appear in a large range of plants where they serve as primary products of photosynthesis and are involved in long distance transport of C and energy storage. Homologues of the enzymes of polyol metabolism, however, have been recently found also in the plant species that do not use sugar alcohols for fulfilling of above mentioned basic functions of carbohydrate metabolism and where their role remains elusive. It is well known that some plants are able to switch between different carbohydrates in response to different stresses, and some produce polyols only at a certain stage of development. It is therefore question of further studies, whether the polyols cannot be observed in other plants under specific stress conditions and in certain developmental stages as a part of stress response. The aim of this Bachelor thesis is to summarize knowledge of mannitol and sorbitol roles, and especially their involvement in...
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Factors controlling tuberization in potato
Suchomel, Ondřej ; Lipavská, Helena (advisor) ; Sikorová, Lenka (referee)
Tuberization of potato plants (Solanum tuberosum L.) is a morphogenetic process of stem transformation into the storage organ - tuber. Tubers emerge preferentially on the underground part of the stem - stolon. Tuberization induction depends on the signals from external environment (primarily photoperiod) and internal plant status. Development of tuber represents a complicated sequence of growth processes regulated primarily by phytohormons with the prominent function of gibberellins and cytokinins. Organs correlations and communication among different parts of plant body plays also very important role in the process. Apart from changes in morphology and cell division occurring in early stages of stolon transformation tuber formation and growth is also accompanied by important metabolic changes. This bachelor thesis is based on a literature review focused on control factors influencing potato tubers formation. The first part of my thesis is devoted to internal factors represented especially by phytohormons. The second part describes the effects of external factors, namely photoperiod, availability of nitrogen and temperature. Key words: Phytohormones, potato, Solanum tuberosum, stolon, induction of tuberization, saccharides
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Phytoremediation:biochemical characteristics of heavy metal hyperacumulators
Lábusová, Jana ; Lipavská, Helena (advisor) ; Podlipná, Radka (referee)
Water and soil pollution by heavy metals is a very serious problem of nowadays. Since the beginning of industrial revolution, the concentration of heavy metals increased sharply in the environment. One way how to decontaminate soils and groundwaters is phytoremediation that uses plants to remediate pollutants from the contaminated sites. This eco-friendly and cost- effective method exploits the ability of plants to take up, translocate, transform and sequester metals. In phytoremediation, the plants that are able to accumulate metals to high concentration are mainly used. These plants are named "hyperaccumulators". Accumulation of metals by plants is affected not only by the capability of plant in question, but to a great extend also by the form and concentration of metal in the soil and environmental conditions. The aim of this Bachelor thesis is to summarize knowledge on impact of heavy metals on biochemical changes in plants, with special emphasis on changes in carbohydrate metabolism.
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Abiotic stress resposes in apple (Malus domestica Borkh.) tissue cultures
Krsek, Daniel ; Pospíšilová, Jana (referee) ; Lipavská, Helena (advisor)
Abiotic stress factors, primarily those which disturb plant water balance, cause extensive crop losses. With regard to sessile lifestyle, many mechanisms how to cope with these unfavourable conditions were developed during evolution of plants. As common impact of many of these stresses like drought, salinity or low temperatures is of osmotic nature, the osmotic adjustment represents important part of plant stress response. Mostly, this component of stress reaction is provided by organic compounds, which are referred to as compatible solutes, including polyhydroxyl compounds (sucrose, sugar alcohols, cyclitols, and oligosacharides) and nitrogen-containing compounds (mainly proline). The effect of these solutes is not only osmotic, but also osmoprotective as they are able to preserve integrity of membranes and macromolecules by mimicking their water envelope. The compatible solutes also contribute to quenching of reactive oxygen species overproduced under these stress conditions. This study is focused on apple (Malus domestica) producing, beside sucrose, sugar alcohol sorbitol as primary photosynthetic product and transporting these carbohydrates along with raffinose family oligosaccharides (RFO) for a long distance. In vitro tissue cultures derived from leaves of two apple cultivars differing in...
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Transformation of potato with S. pombe mitotic activator cdc25
Ševčíková, Hana ; Lipavská, Helena (advisor) ; Cvrčková, Fatima (referee)
Tuberization is an important process in potato that is governed by a complex of environmental as well as internal factors. As a morphogenic process, it is closely connected with regulation of frequency and orientation of cell division. Thus, the aim of this thesis was to transform potato with mitotic activator cdc25 from Schizosaccharomyces pombe (Spcdc25) and to follow the resulting changes in potato phenotype with a special focus on tuber formation. In previous studies with tobacco, it has been shown that the expression of the above mentioned Spcdc25 gene results in dramatic changes in morphology (leaf structure, restricted root development and growth, and also remarkable developmental change - acceleration of flowering). Moreover, many other characteristics that can be induced in control by cytokinin application have been observed (e.g. cytokinin independent de novo shoot formation, carbohydrate metabolism changes). The two last characteristics - cytokinins independency of morphogenic process and changes in carbohydrate metabolism (e.g. increased starch deposition) - are important from the point of view of expected changes in characteristic of Spcdc25 transgenic potato. To transform potato, the preparation of a plasmid carrying construct with suitable selectable marker was necessary. From original...
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