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Natural sources and sinks of volatile chlorinated hydrocarbons in the spruce forest ecosystem
Štangelová, Pavla ; Tesařová, Eva (advisor) ; Pavlík, Milan (referee)
Biogeochemical cycle of chlorine, particularly the formation of organically bound chlorine is still not well understood. In continental ecosystems chlorides act as source of chlorine, and also as a stress factor. Chlorides originate from precipitation of marine cloud masses. Organically bound chlorine in the environment is formed naturally by biotical and abiotical way. The biotical factors are microorganisms, plants, soil enzymes and animals. Volatile chlorinated hydrocarbons (VOCl) represent one group of organically bound chlorines. Several volatile chlorinated hydrocarbons reacts with atmospheric ozone, consequently causing depletion of the ozone layer. The most important known terrestrial source of volatile chlorinated hydrocarbons is the spruce forest ecosystem. Chlorine in the soil can be transformed by microorganisms into organically bound chlorine or translocated by transpiration stream in plants, where they are also transformed enzymatically into organically bound chlorine, and both of them can be emitted into the atmosphere. Too large amounts of chloride can affect the physiological functions of plants. In this thesis experiments were designed for measuring the natural emissions of volatile halogenated hydrocarbons from plants and fungi, with various periods of incubation, and also to...
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Natural sources and sinks of volatile chlorinated hydrocarbons in the spruce forest ecosystem
Štangelová, Pavla ; Tesařová, Eva (advisor) ; Pavlík, Milan (referee)
Biogeochemical cycle of chlorine, particularly the formation of organically bound chlorine is still not well understood. In continental ecosystems chlorides act as source of chlorine, and also as a stress factor. Chlorides originate from precipitation of marine cloud masses. Organically bound chlorine in the environment is formed naturally by biotical and abiotical way. The biotical factors are microorganisms, plants, soil enzymes and animals. Volatile chlorinated hydrocarbons (VOCl) represent one group of organically bound chlorines. Several volatile chlorinated hydrocarbons reacts with atmospheric ozone, consequently causing depletion of the ozone layer. The most important known terrestrial source of volatile chlorinated hydrocarbons is the spruce forest ecosystem. Chlorine in the soil can be transformed by microorganisms into organically bound chlorine or translocated by transpiration stream in plants, where they are also transformed enzymatically into organically bound chlorine, and both of them can be emitted into the atmosphere. Too large amounts of chloride can affect the physiological functions of plants. In this thesis experiments were designed for measuring the natural emissions of volatile halogenated hydrocarbons from plants and fungi, with various periods of incubation, and also to...
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Detection of Hsp70 protein in plants exposed to various stress factors.
Lengálová, Alžběta ; Hýsková, Veronika (advisor) ; Liberda, Jiří (referee)
! Plants are continuously exposed to various stress conditions. Being sessile, they are not able to escape from adverse conditions. Therefore, they have developed specific defence mechanisms. Most studies focus on plant responses to a single type of stress. However, plants in nature must cope with a variety of stresses at the same time. In this work, the effects of heat shock on the interaction of tabaco (Nicotiana tabacum L.) with the Potato virus Y (PVY) were investigated. Obviously, heat stress is associated with the synthesis of Hsp70 protein, which has many important functions alleviating adverse effects of stress conditions (e.g. Hsp70 participates in refolding or degradation of damaged proteins and protein syntetis de novo). The effect of Hsp70 during viral infection is still not fully understood, some studies revealed Hsp70 as a part of viral multiplication and transport processes in plant. In the first experiment performed in this work, higher levels of PVYNTN virus was found in tobacco plants that have been exposed to heat shock after inoculation than in plants only infected. The amount of the virus corresponded with the amount of Hsp70 protein detected immunochemically using a specific antibody. It seems that the plant response to combination of heat stress with viral infection is a...
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Metabolic pathways involved in the regulation of bioactive cytokinin levels in plants
Žižková, Eva ; Motyka, Václav (advisor) ; Pernisová, Markéta (referee) ; Hoyerová, Klára (referee)
SummarySummarySummarySummary Cytokinins (CKs) are important group of plant hormones involved in a wide range of physiological and developmental processes. Endogenous levels of CKs as well as proportions of individual CK forms and derivatives are not constant and differ among plant species. The amounts of biological active CK forms (free bases and ribosides) are regulated through tangled machinery of metabolic conversions including biosynthesis, conjugation and degradation pathways. The main object of this thesis was to characterize the metabolic pathways involved in the regulation of bioactive CK levels in plants especially via CK biosynthesis with aspect to the environmental stimuli and via N- glucosylation pathway. It was shown, that light signal is an important input for modulating some CK-related genes and CK levels in Arabidopsis plants. The complex diurnal expression profiles of CK-biosynthetic genes (AtIPT1 - AtIPT9) in Arabidopsis plants indicated a strong dependence of AtIPT1 and AtIPT5 on light/dark phase in leaf rossetes. In contrast, no diurnal oscillation of AtIPT transcript levels was recorded in roots. Although the content of endogenous CKs was not constant in plants and varied during a day, no statistically significant correlation between light/dark cycle and oscillation in CK levels was...
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The effect of abiotic stress on cucumber plants (Cucumis sativa L.)
Plisková, Veronika ; Hýsková, Veronika (advisor) ; Müller, Karel (referee)
The exposure of plants to high salt concentrations causes accumulation of sodium ions. This leads to the inability of the plants to uptake water, a disturbance of ion homeostasis, a decrease in photosynthesis and oxidative stress. As a result of the salt stress, the availability of NADPH decreases. The adaptation to the concentrations of salt depends on plant's ability to compensate for the decreased availability of NADPH, which can be further used in antioxidative cycles and the synthesis of antioxidative compounds and osmoprotectants. In this work, the reduction of relative water content, a decrease in the Rubisco enzyme activity, an increase of Hsp70 in the leaves and an increase in the accumulation of sodium ions was shown in cucumber plants (Cucumis sativa L. convar. Jogger F1) exposed to salt stress (100 mM NaCl). As a consequence of salt stress, an increase in the activity of NADPH providing enzymes was found. Particularly on the second and third day of salt stress, an increase in the activity (up to 270 %) of: NADP-isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, NADP-malic enzyme, non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase in leaves was detected. The activity of less abundant NADP-dehydrogenases (glucose 1-dehydrogenase, gluconate 2-dehydrogenase, galactose...
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