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Rozhovory přes kutikulu
KOUTKOVÁ, Simona
Leaves of the plants communicate with their environment on the interface formed by epidermis with stomata and cuticle. Cuticle layer, composed of cutin and waxes, represents a barrier, which protects a plant from excessive water loss, but not only this. The changes of these boundaries are dependent on the environmental conditions, especially light (PPFD) and ambient CO2 concentration (Ca). This work tries to answer these questions: How is the availability of CO2 inside the leaf (Ci) altered? How is the development of epidermis related to cuticle formation?
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The phenomenon of Foliar Water Uptake - mechanisms and consequences with a focus on temerate plant species
Oramová, Viktorie ; Lhotáková, Zuzana (advisor) ; Ponert, Jan (referee)
The ability of plants to absorb water through leaves has been a matter of the sientific discussion for a long time. Among the epiphytic species (tilandsies for example), reduced root system and foliar water uptake (FWU) is considered an adaptation for life in soil-less environment, and FWU is a necesssity. It was surprising, that the same ability has been discovered in plant species with normally developed root system. Over the time, new pieces of evidence about FWU in broad range of plant species has been published and FWU is getting universal for all plants, across the taxonomic groups or biomes, including temperate zone. The systematic focus on FWU and continuity of its research is lacking and therefore the knowledge about FWU is still only partial. This bachelor's thesis is focused on mechanisms of FWU and the leaf structures that may mediate it. The ability of water to pervade cuticle through aquatic pores is discussed, together with the possibility of water absorption by stomata, trichomes, hydathodes or epiphylic organisms. Another discussed topic is the use of this water by plant - improving of the water regime, refilling of the embolized xylem vessels, possible exudation by roots etc. The matter of FWU has other consequences on the ecosystem level, like in water cycle or the plant's...
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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...
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Mechanisms of epidermal cells polarization in plants.
Vojtíková, Zdeňka ; Žárský, Viktor (advisor) ; Soukup, Aleš (referee)
Plant epidermal cells form contact area of the plant, they protect it from impacts of surrounding environment and they mediate the communication with its neighbourhood. In the epidermis there are evenly distributed several cell types with quite specialized morphology (pavement cells, trichomes and guard cells) due to the polarization mechanisms. The cytoskeleton and signal molecules of ROP GTPase family promote the polarized growth. Thanks to polarized growth the cells reach their shapes. The cytoskeleton responds to the signal by expanding the cell, helps with targeting of the secretion to the sites of active growth and mediates polarized formation of the cell wall. On the upper side of the epidermis the cuticle and layer of epicuticular waxex is secreted. The secretion of cuticular components is baso-apicaly polarized. This work summarizes the mechanisms of the polarization in plant epidermal cells discoverd untill now.
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Potassium in plant osmoregulation
Kholová, Kateřina ; Tylová, Edita (advisor) ; Konrádová, Hana (referee)
Potassium is very mobile in plants and is transported across membranes using transporters and channels. It is present in the ionic form K+ in plants. Also, in the form of this ion, K+ is taken up by plants from the soil solution. The uptake is mediated by the transporter HAK5 and by the channel AKT1. The transfer of K+ to the xylem is provided by the channel SKOR and the transporter KUP7. The role of potassium as an osmotically active element is crucial. K+ helps to regulate the amount of water in the cells and thus to maintain the turgor. Turgor is important for maintaining the shape of the plant cells and for its growth. Stomatal guard cells are used as a model system for describing processes related to the K+ osmotic function. Movement of K+ is involved in the regulation of opening and closing of stomata on the principle of turgor changes. Transport of K+ into guard cells is provided by channels KAT1, KAT2, AKT1 and AKT2. On the contrary, K+ release is mediated by the channel GORK on the plasma membrane and TPK1 on the tonoplast. K+ supports also the transport of assimilates in the phloem, where the channel AKT2 plays a role. The osmotic functions of K+ are the main topic of this bachelor thesis, which summarizes current knowledge about transport mechanisms necessary for the function of K+ as osmotically...
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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
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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...
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Vývoj průduchů dvouděložných rostlin: vliv faktorů prostředí
KALISTOVÁ, Tereza
Stoma are microscopic structure in plant epidermis consisted of two guard cells and a pore between them. Their development is influenced by internal processes and different environmental factors as light, water availability or concentration of CO2. Carbon in CO2 has two stabile isotopes,12C and 13C, which have different weight and concentration in atmosphere. The 13C abundance (13C) in leaf tissue reflects the environmental condition experienced during the leaf live span. Here I studied: i) development of epidermal cells (primarily of stomata) during first true leaf ontogeny in Lepidium sativum and Arabidopsis thaliana and ii) effect of milling the dry leaf tissue in microtubes on 13C.
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Regulation of stomatal development by environmental conditions and physiological processes in the leaf
VRÁBLOVÁ, Martina
Stomatal development and its regulation by environmental conditions (light, CO2 concentration) and physiological processes in the leaf of higher plants were investigated. The study was based on the assumptions that stomatal development should be regulated by signals coming from both external environment and leaf interior, and that the signal should be transduced from cotyledons to leaves. Transgenerational effect in stomatal development was also studied. Molecular and physiological approaches were applied to reveal the relationship between leaf environment, stomatal development, stomatal function and leaf physiology.
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