National Repository of Grey Literature 42 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Is CO2 fertilization responsible for plant growth enhancement across different biomes?
Pyšek, Ivan ; Šímová, Irena (advisor) ; Lhotáková, Zuzana (referee)
Production of plant biomass depends on abiotic and biotic factors, these factors vary across biomes. Concentration of carbon dioxide in the atmosphere is one of the abiotic factors. The effect of this factor on plant is intensively studied. Current climate changes includes global warming, that is influenced mainly by anthropogenic activity (burning fossil fuels and the consequent increase in the concentration of greenhouse gases: carbon dioxide, methane etc.). Due to the increased concentration of carbon dioxide in the atmosphere, plants likely increase their growth, photosynthetic activity, decrease their stomatal conductance and the rate of transpiration. Increasing concentration of CO2 can thus have a positive impact on plants. The FACE method monitores plant reactions to enhanced concentrations of carbon dioxide in the atmosphere in natural environment. The response of plants to increasing concentration of carbon dioxide is influenced by biotic and abiotic factors, which vary across biomes, and also by the type of plant metabolism (C3 and C4 metabolism). Plants with C3 metabolism react to increased concentrations of carbon dioxide immediately, but this response is diminished as they acclimatize over the years. In contrast, plants with C4 metabolism react with a delay, but there is not such a...
Flexibility of cyclitol metabolism as a component of effective plant defense against water scarcity
Skulníková, Barbora ; Konrádová, Hana (advisor) ; Lhotáková, Zuzana (referee)
This bachelor thesis is focused on plant defence mechanisms against drought stress and salinity stress associated with the production of compatible solutes, while attention is paid to the accumulation of cyclic sugar alcohols, myo-inositol and its methylated derivatives. It describes the occurrence of these substances, their biosynthesis and function in plants. Another part of this thesis focuses on the crystalline ice plant (Mesembranthemum crystallinum), which is an important producer of these substances and serves as a model used to study the stress response in plants. It describes its life cycle and especially the mechanisms that makes it resistant to drought stress and salinity. The last chapter is dedicated to the knowledge gained through the study of transgenic plants, which were prepared using genes from crystalline ice plant and other stress tolerant plants.
Hydraulic redistribution and within community plant relations
Lörinc, Filip ; Lhotáková, Zuzana (advisor) ; Tylová, Edita (referee)
Hydraulic redistribution is a widespread process of passive water transport through the plant root system along the gradient of water potential. This process significantly affects other plant belowground and aboveground processes. Water can be transported in several directions by hydraulic redistribution. The aim of the first part of this thesis is to summarize the knowledge about the operation of hydraulic redistribution. It describes the causes and consequences of the hydraulic redistribution as well as its main types. Subsequently, mainly vertical hydraulic redistribution is observed, the main components of which are the hydraulic lift and the hydraulic descent. The second part focuses on how vertical hydraulic redistribution can influence the interactions among plants and the functioning of the whole ecosystem. The answer to this question is sought in the savanna plant life, which is composed of scattered trees and their grassy understory. Savanna plants are exposed to dry and wet seasons, which creates a changing soil gradient of water potential throughout the year, which is of great interest for hydraulic redistribution research. This thesis shows that woody species have a competitive advantage over the grassy understory due to the presence of a hydraulic descent. Competition between trees...
Laboratory spectroscopy for selected Krkonoše Mts. tundra vegetation species
Tomcová, Jana ; Červená, Lucie (advisor) ; Lhotáková, Zuzana (referee)
Laboratory spectroscopy for selected Krkonoše Mts. tundra vegetation species The diploma thesis is focused on testing the methodologies of measuring the reflectance of grasses from the tundra of Krkonoše Mountains (Nardus stricta, Molinia caerulea, Calamagrostis villosa). The spectoradiometer ASD FieldSpec 4 Wide-Res with added contact probe ASD Plant Probe is used for measurements. Since it is not common to measure such narrow leaves that do not cover the whole FOV, the thesis is looking for methodologies that are the most repeatable and influenced by a minimum of errors. Factors influencing the measurement results are also monitored. Furthermore, the differentiation of the studied species is observed based on their spectral properties. Based on the measured data the medians and standard deviations are calculated and compared among each other. An analysis of variance (ANOVA) is used to determine the bands where the influence of individual factors is more apparent and where the individual grasses are distinguishable. As the most suitable methodologies for measuring grasses depend on the grasses structures and properties, the best methodology is different for each of selected species. The two layer leaf measurement is most suitable for the Nardus stricta, the measurement of the abaxial sides of leaves fits...
Stomata opening and closure regulation in respect to osmotic stress
Hofírková, Miroslava ; Hála, Michal (advisor) ; Lhotáková, Zuzana (referee)
Stomata are structures located in higher plants' epidermis and they regulate mainly CO2 intake and transpiration. The stomata are important for plants' protection against excessive water loss during osmotic stress. This thesis is a literary research summarizing stomatal movements regulation during osmotic stress. The main part of the thesis is focused on stomatal closure with the help of ABA under water deficiency conditions. There are the ABA synthesis, transport and its impact on stomata described in individual chapters. The ABA early signalling pathway and an ionic channel regulation are described in detail on the basis of the published data. The second part of the thesis is about second messengers produced by ABA and their impact on stomatal movement regulation. The special attention is paid to hydrogen peroxide and nitric oxide and their contribution to stomatal closure. The last part is about passive (hydraulic) stomatal closure. Keywords: plants, stomata, osmotic stress, ABA, stomatal movements
Effect of water supply on structure and selected physiological parameters of leaf in woody species.
Horešovská, Michaela ; Lhotáková, Zuzana (advisor) ; Votrubová, Olga (referee)
Woody plants must cope with drought as it is one of the main factors of the ongoing climate change. The ability of woody plants to adapt to this stressor determines whether they will survive in constantly changing environmental conditions. The deciduous trees of European temperate forests are not as adapted to drought as Mediterranean trees and shrubs, and therefore the lack of water is a major stress for them. Leaf turned out to be the most flexible plant organ in its response to drought. The aim of this work is to summarize the knowledge about the effect of water deficit on the anatomical structure of leaf and its selected physiological parameters. The first part of this thesis is focused on the drought affecting European tree species and their various defensive strategies against this factor. It mainly describes the modification of leaf's anatomy structure as their defensive reactions observed in dermal, ground and vascular tissue. The second part of this thesis is devoted to the influence of water deficit on the selected leaf's physiological processes, especially on transpiration and photosynthesis, and the key role of stomata closure on both of these physiological processes. Drought causes changes in leaf anatomical structure and its physiological functions. The leaf's developmental stage at...
Study of quantitative parameters of Norway spruce needle structure under the effect of elevated CO₂ concentration and different irradiance
Kubínová, Zuzana ; Lhotáková, Zuzana (advisor) ; Urban, Otmar (referee) ; Gebauer, Roman (referee)
Zuzana Kubínová: Study of Quantitative Parameters of Norway Spruce Needle Structure under the Effect of Elevated CO2 Concentration and Different Irradiance, Doctoral Thesis, Prague 2019 Abstract Atmospheric concentration of CO2 is increasing, while its influence on plants is still not fully elucidated. Norway spruce (Picea abies L. Karst.) is an abundant conifer tree in European temperate and boreal forests, which behave as carbon sink in the global carbon cycle. The physiological response to elevated CO2 concentration may be interconnected with changes in leaf anatomy and morphology. Needle structure is also determined by other factors in addition to CO2 concentration, irradiance being the most important one. Thus, effect of irradiance was also included in our studies. The effects of elevated CO2 concentration and irradiance on Norway spruce needle structure were studied using new applications of well-established quantitative methods and novel methods enabling effective and unbiased analysis of needle structural traits. The General Procrustes analysis showed to be effective for needle shape on cross section comparison and the disector method proved to be suitable for chloroplast number estimates. The influence of elevated CO2 concentration and different irradiance on needle structure was studied at two...
Physiological responses of woody species to urban environment
Petrouová, Lenka ; Lhotáková, Zuzana (advisor) ; Lipavská, Helena (referee)
Trees are an important functional element in urban ecosystems. The urban environment has a number of abiotic stress factors for trees and their interactions are based on the overall physiological condition of the trees. Abiotic stress factors include air pollution, space constraints, reduced water availability, increased temperature, and precipitation. In addition to abiotic factors, trees in the city face stressful conditions brought on by climate change, which are increasing in severity and have a measurable impacts on urban tree growth. Climate change is manifested mainly by elevated air temperatures, changes in quantity and distribution of precipitation, and increased concentrations of carbon dioxide in the atmosphere. This bachelor's thesis is focused on the responses of selected woody species in urban environments and their adaptive abilities in the context of changing climatic conditions. Growth is the main observable response of woody species to environmental changes. In particular, increased growth has been recorded in relation to rising temperature and carbon dioxide levels. Specific differences between woody species in functional parameters can be utilized to improve quality of life in human environments Trees are highly valuable in urban ecosystems and perform a range of functions,...
Increasing plant drought resistance by priming methods: the role of antioxidant capacity changes
Popelářová, Anna ; Lipavská, Helena (advisor) ; Lhotáková, Zuzana (referee)
When there is a lack of water in the soil, the plant is subject to stress during which reactive oxygen species (ROS) are formed and the water content in the tissues decreases. ROS cause oxidative damage, which the plant tries to prevent by antioxidation systems action. The osmotic adjustment process ensures water maintenance in the plant. Priming can be thought of as a treatment of plants aimed at increasing stress resistance. This thesis is mainly focused on summarizing information related to priming in connection with drought tolerance improvement and related changes in the activities and amount of antioxidation systems and osmolytes. So far, seed priming methods are probably the most explored, these include hydropriming, osmopriming and priming with elicitors. Priming in the vegetative phase of growth is mainly associated with the application of elicitors. Transgenerational priming has an impact on the progeny of treated plants. Priming-induced changes are species-specific and in some cases may affect the plants for a longer period.

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