National Repository of Grey Literature 39 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
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.
How does the leaf structure determine the leaf optical properties.
Peychlová, Anna ; Lhotáková, Zuzana (advisor) ; Tylová, Edita (referee)
An internal leaf structure determines the way the light passes through the leaf and, thus, in this way it affects the use of the light in photosynthesis. The light reaching the leaf can be reflected, absorbed or transmitted. Leaf reflectance properties depend on the wavelength of irradiation and on the physical, structural and chemical properties of a leaf. Thereinafter, this Bachelor thesis briefly describes spectral methods used to study leaf optical properties. Furthermore, the thesis focuses on leaf anatomical structures and their effect on leaf optical properties, mainly in visible region of electromagnetic radiation (400-700 nm) and in near- infra-red region (700-2300 nm). The emphasis is given to the following anatomical properties and structures: epidermis, cuticle, trichomes, mesophyll structure, leaf thickness, chloroplast movement, chlorophyll content and distribution. The aim of the thesis is to summarize current knowledgeon this topic. Key words: leaf anatomy, leaf optical properties, reflectance, intercellular spaces, radiative transfer
Mechanisms of extreme drought tolerance in resurrection plants
Termanini, Sebastian ; Lipavská, Helena (advisor) ; Lhotáková, Zuzana (referee)
Drought is one of the abiotic stresses that plants have to fight with from the beginning of their transition to land. However, there is a systematically incoherent group of plants that can solve extreme water scarcityand still effectivelyprosper. A high degree of dehydration involves a number of problems including osmotic stress, the accumulation of reactive oxygen species (ROS), or protein degradation. However, drought-tolerant plants have evolved mechanisms to deal with these problems. For protection against ROS they activate antioxidant enzymes and accumulate non-enzymatic antioxidants, which can quench ROS. These plants use a wide spectrum of amino acids and carbohydrates against the osmotic stresses, ranging from the ubiquitous and abundant carbohydrates like sucrose, till the trehalose scarce in plants. None of the plants relies on a single substance, instead, plants depend on species-specific cocktails of protective agents, through which they acquire their tolerance. The studies of those plants and their mechanisms of tolerance seem to be a perspective way for selection of preferable target genes suitable for the development of crops tolerant to desiccation. Key words: antioxidant systems, dehydration, drought, LEA, octulose, polyols, RFO, resurrection plants, sucrose, trehalose

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