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Physiological basis of the tradeoff between growth and defense against abiotic stress: the role of carbon balance
Doložílek, Jakub ; Konrádová, Hana (advisor) ; Petrášek, Jan (referee)
Similarly to other organisms, plants must coordinate growth and development with their energetic status. Besides that, considering their sessile way of life, they need to adapt very precisely to the environmental conditions of their habitats. However, from the point of view of invested resources, the defence mechanisms may be very expensive, and so, their activation is usually accompanied by a restriction of growth. Hence, establishing functional dynamic balance between investment to growth and defensive reactions ("G-D tradeoff") is essential for the plants fitness, competitiveness and reproduction success. The thesis examines the mechanisms that are fundamentally contributing to this balancing. In this work, evolutionarily conserved axis coordinating growth and development with energetic status consisting of TOR kinase, positive growth regulator during favourable conditions, and her antagonist, the SnRK kinase, inducer of resources mobilization in purpose of realizing defensive measures securing energetic homeostasis, is discussed. Further, this thesis focuses on plant-specific pathway which links the TOR-SnRK1 axis with perception of environmental conditions. The main components of this pathway are the SnRK2 kinases, coordinators of specific defensive reactions, PP2C phosphatases and...
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Role of plants in the greenhouse gas budget of a sedge fen
NOVOTNÁ, Jitka
Wetlands play an important role in the global carbon cycle because they fix or release carbon dioxide (CO2) and are a source of atmospheric methane (CH4). The dynamics of the exchange of these greenhouse gases is determined mainly by the height and dynamics of water level, temperature and vegetation structure and biomass. The aim of this study was to evaluate the effect of plants with a dominant sedge, Carex acuta, on CO2 and CH4 emissions from a sedge fen on a model site ?The Wet Meadows? near Třeboň. This study included field research using a method of manual emission chambers in order to monitor the differences in the emissions between hummocks with vegetation and hollows without vegetation. In addition, aboveground plant biomass, water level and temperature were followed. The field research was supplemented with a mesocosm experiment in which the influence of water regime on C. acuta biomass production was evaluated. The results of the field research show that water level had a significant effect on CO2 emissions only in the hollows. Soil temperature was an important factor on both micro-sites. The presence and biomass of the plants had a substantial effect on the amounts of CO2 emissions, but only in the second part of the vegetation season, when the plant aboveground biomass reached its seasonal maximum. CH4 emissions were significantly influenced by the water level and its previous dynamics but not by temperature. An important factor was also the presence of sedge hummocks, which vented considerable amounts of CH4 into the atmosphere when their basal parts were flooded. Fairly small amounts of CH4 were mediated by the plants at water levels between -20 cm and the soil surface. A conceptual model has been created for the conditions of 2014 in order to estimate the effect of the C. acuta dominated vegetation of the hummocks on carbon emissions and its balance. The carbon assimilation into plant biomass exceeded not only the carbon emissions mediated by the plants, but also the emissions from the whole hummocks. Approximately 130 g C m-2 per vegetation season was stored into the soil owing to the plants. The mesocosm experiment indicated that the plants of C. acuta formed the greatest belowground biomass as well as total biomass in the limosal ecophase followed by the plants subjected to a spring flood.
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Carbon sequestration by forest ecosystems in canging climate.
Hlaváčková, Lucie ; Lhotáková, Zuzana (advisor) ; Urban, Otmar (referee)
The global carbon cycle is in the focus of the scientists' interest, because understanding carbon sinks and their relationships can show the solutions of problems related with increasing CO2 concentration in the atmosphere in the future. I focused on the role of forests ecosystems in this carbon cycle. All forests cover almost one third of the Earth's land area. By photosynthesis they bind big part of atmospheric carbon to their biomass. Sink strength of forest can differ according to the type of biome, forest stand age and actual climatic conditions. Forest biomes can be generally divided according to the latitude to three groups: tropical forest biomes, temperate forests and boreal forests. The size of carbon stock decreases in this order. Other parameters, such as net primary production and respiration differ in dependence on the particular ecosystem. Tropical rain forests represent great carbon stock, but their deforestation causes massive C emissions back to the atmosphere. Boreal forests aren't considered as important carbon sink, but they influence local climate. Some speculations can also appear about the old forests. It is possible to find authors, who claims, that old forests are no more carbon sinks, so that their carbon balance is neutral. Many surveys prove that they bind less carbon...
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Carbon sequestration by forest ecosystems in canging climate.
Hlaváčková, Lucie ; Lhotáková, Zuzana (advisor) ; Urban, Otmar (referee)
The global carbon cycle is in the focus of the scientists' interest, because understanding carbon sinks and their relationships can show the solutions of problems related with increasing CO2 concentration in the atmosphere in the future. I focused on the role of forests ecosystems in this carbon cycle. All forests cover almost one third of the Earth's land area. By photosynthesis they bind big part of atmospheric carbon to their biomass. Sink strength of forest can differ according to the type of biome, forest stand age and actual climatic conditions. Forest biomes can be generally divided according to the latitude to three groups: tropical forest biomes, temperate forests and boreal forests. The size of carbon stock decreases in this order. Other parameters, such as net primary production and respiration differ in dependence on the particular ecosystem. Tropical rain forests represent great carbon stock, but their deforestation causes massive C emissions back to the atmosphere. Boreal forests aren't considered as important carbon sink, but they influence local climate. Some speculations can also appear about the old forests. It is possible to find authors, who claims, that old forests are no more carbon sinks, so that their carbon balance is neutral. Many surveys prove that they bind less carbon...
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The possibilities of bioenergy production in a chosen agricultural farm in higher elevations
BÁRTA, Pavel
The chosen agricultural enterprise, Agricultural Cooperative Skalka {--} Jankov farms in the South Bohemia region near the city of České Budějovice. Analysis of the inner structure of the agricultural system was calculated for a ten-year period 1998 {--} 2007. Data used for the analysis include: harvest area, yield of individual crops, mineral fertilizer consumption and cattle stock. On the basis of this analysis, using carbon balance principles, variants of agricultural inner structure project have been worked out, aimed at bioenergy production: cereals for production of bioethanol, raps for biodiesel production, biogas.
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System analysis of chosen agricultur corporation in middle altitude with focusing on bioenergy production
SOUKUP, Miroslav
Chosen agriculture farm: Dubné corporation is in South Bohemia region. Analysis of inner structure of agricultural system was calculated for ten-year period 1997 {--} 2006. Data used for analysis: acreage and yield of individual crops, consumption of mineral fertilizers, cattle stock. On the basis of this analysis, using carbon balance principle, variants of agricultural inner structure project have been worked out, aimed at bioenergy production: cereals for production of bioethanol, raps for production of oil, biogas.
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