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Phosphate binders
Kalina, Lukáš ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The work deals with the preparation and study of polyphosphate composites. Aluminum phosphates provide some unusual properties like high-heat resistance in terms of inorganic binders. The addition of chromium in the form of Cr2O3 or directly the bond with the aluminum-chromium-phosphate can improve the properties of this binder. Highly viscous Al2Cr(H2PO4)9 and Al3Cr(H2PO4)12 binders were prepared by dissolving Al(OH)3 and CrO3 in 85% phosphoric acid, and mixed with Al2O3 and Cr2O3 fillers. The composites were cured in the furnace at 150 °C for 24 h under pressure of 10 MPa. During the annealing at temperatures up to 1 500 °C changes in chemical structure of the cured composites were observed, leading to the understanding of the creation of crystalline phases and their eventual changes. The characterization of binders was mainly based on FT-IR, EDAX, TG-DTA and optical microscopy analyses.
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Electrode Active Materials for Lithium-Ion Accumulators
Čech, Ondřej ; Oriňáková, Renáta (referee) ; Paidar,, Martin (referee) ; Sedlaříková, Marie (advisor)
This doctoral thesis deals with synthesis and characterisation of electroactive electrode materials for li-ion batteries and accumulators. The work is divided into two main parts. One deals with LiFePO4 based cathode composite electroactive material and in the second is described the synthesis and utilization of monoclinic TiO2(B) as an anode for li-ion cell. The main aim of the work is to relate the synthesis procedure and structural properties of both materials to its electrochemical preformance.
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Effect of exodermis differentiation on nutrient uptake localization in root
Janoušková, Jana ; Tylová, Edita (advisor) ; Konrádová, Hana (referee)
Plants are able to cope with changing environmental conditions or withstand its adverse effects due to their plastic development. One way to adapt to fluctuating amounts of nutrients and water in the environment or the presence of toxic substances is to regulate the movement of substances between the plant and the environment. Beside other, this regulation is also possible at the level of the root system, by the formation of apoplastic barriers endodermis and exodermis. Some species posses endodermis only, in others exodermis in hypodrermal layers of the root can be found. These barriers differentiate in three stages and prevent free movement of coumpounds though apoplast. The transport to the symplast is the key point of regulating the uptake of substances into the plant and the endodermis is the fundamental structure. The presence of exodermis, however, affects the apoplast permeability of the surface root layers and can therefore influence the involvement of the primary cortex cells in the uptake of substances from the environment. In this work the impact of phosphate deficiency on the formation of apoplastic barriers was studied focusing on exodermis and the effect of its differentiation on the occurrence of membrane transporters and involvement of primary cortex cells in the uptake of...
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Control of lateral root development in response to availability of principal mineral nutrients.
Halamková, Daniela ; Tylová, Edita (advisor) ; Smetana, Ondřej (referee)
Lateral roots are, due to their large absorption surface, a part of the root system with significant importance for the plant's ingestion of water and nutrients. Their development depends on heterogeneity of soil environment, which enables the plant to optimize the acquisition of resources under current conditions. The availability of mineral nutrients (type of nutrient, form, distribution in soil and mobility) is one of key factors that determine root system morphogenesis. Another important aspect is the amount of nutrient in the plant; in other words, the plant's current demand for the element. The most important nutrients that influence the architecture of the root system are two macroelements - nitrogen and phosphorus. Both of these elements trigger positive and negative effects on the development of lateral roots. Nitrate, important source of nitrogen, induces two entirely different regulatory mechanisms of lateral root development. Under nitrogen limiting condition, a local stimulation of lateral root elongation is triggered in nitrate-rich patches. This response integrates the signalling pathways of auxin and nitrate. In contrast, high and homogenous availability of nitrate in rhizosphere (≥ 10 mM) causes inhibition of lateral root growth. This systemic inhibitory effect was similarly...
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Study of acid phosphatase in pea and tobacco
Šandová, Sandra ; Ryšlavá, Helena (advisor) ; Tichá, Marie (referee)
Phosphatases catalyze the hydrolytic fission of orthophosphoric acid ester. They are generally divided into acid and alkaline phosphatases according to their pH optimum. There was preparated the extract of leaves Nicotiana tabacum L. and Pissum sativum. Furthermore, there were determinated pea and tobacco phosphatases's rate constants. Reaction speed katalyzed by tobacco phosphatase is 10,0 mol/min.ml and by pea phosphatase 38,0 mol/min.ml using paraNP - phosphate as a substrate. Using a substrate phospho - L serine the reaction speed katalyzed by phosphatase of tobacco is 1,8 mol/min.ml and by phosphatase of pea is 0,4 mol/min.ml. Michaelis constant Km is 1,8 mM for tobacco phosphatase and 8,5 mM for pea phosphatase using paraNP - phosphate. Using a substrate phospho - L serine Michaelis constant Km of phosphatase of tobacco and pea is the same - 4,0 mM. The pH optimum of pea phosphatase is 5,0 using paraNP - phosphate as a substrate and 6,0 using phopho - L serine. pH optimum of tobacco phosphatase is 5,4 using paraNP - phosphate and 7,0 using phospho - L serine. Temperature optimum for pea phosphatase is 60 C and for tobacco phosphatase 55C.
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Effect of exodermis differentiation on nutrient uptake localization in root
Janoušková, Jana ; Tylová, Edita (advisor) ; Konrádová, Hana (referee)
Plants are able to cope with changing environmental conditions or withstand its adverse effects due to their plastic development. One way to adapt to fluctuating amounts of nutrients and water in the environment or the presence of toxic substances is to regulate the movement of substances between the plant and the environment. Beside other, this regulation is also possible at the level of the root system, by the formation of apoplastic barriers endodermis and exodermis. Some species posses endodermis only, in others exodermis in hypodrermal layers of the root can be found. These barriers differentiate in three stages and prevent free movement of coumpounds though apoplast. The transport to the symplast is the key point of regulating the uptake of substances into the plant and the endodermis is the fundamental structure. The presence of exodermis, however, affects the apoplast permeability of the surface root layers and can therefore influence the involvement of the primary cortex cells in the uptake of substances from the environment. In this work the impact of phosphate deficiency on the formation of apoplastic barriers was studied focusing on exodermis and the effect of its differentiation on the occurrence of membrane transporters and involvement of primary cortex cells in the uptake of...
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How works mycorrhizal pathway in phosphorus acquisition?
Konečný, Jan ; Jansa, Jan (advisor) ; Janoušková, Martina (referee)
The plant takes up mineral nutrients by its roots from the soil. Minerals are available in the soil solution in the form of ions and can be translocated across the cytoplasmatic membrane into the cell of the plant. If the plant is alone, we talk about direct pathway. In case of some minerals, which are not available so easily, the plant finds solution in mutualistic relationship - the mycorrhizal symbiosis. By mycorrhizal pathway the nutrients come from much larger volume of soil, than the plant could reach, and intake of low-mobile elements, like phosphorus, becomes facilitated. How is the phosphorus taken up through mycorrhizal pathway, how is it regulated and accessory knowledge are the topic of this bachelors thesis.
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Regulation of phosphate uptake by strigolactones
Balín, Michal ; Vaňková, Radomíra (advisor) ; Tylová, Edita (referee)
This Bachelor thesis is focused on the reactions of plants to low levels of available phosphorus, which is essential element for plant nutrition. In the context of plant stress, plant hormones strigolactones play very important role. Strigolactones influence growth and development of the whole plant. Biosynthesis of strigolactones increases under phosphate deficiency. This thesis consists of three parts. The first part is concentrated on phosphorus, its compounds and its availability in the environment. The second part is mainly dedicated to phosphate stress - its sensing by plants, their adaptations to stress and local as well as long distance signalling. Attention is also paid to phytohormones, namely auxins, cytokinins, gibberellins, ethylene, abscisic acid and other signal molecules, like sucrose, the phosphate molecule itself and microRNAs. The third part is focused mainly on the structure, biosynthesis, signal transduction and the mode of action of strigolactones during phosphate stress. Keywords: phosphate, deficiency, strigolactone, phytohormones, stress
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Study of acid phosphatase in pea and tobacco
Šandová, Sandra ; Ryšlavá, Helena (advisor) ; Tichá, Marie (referee)
Phosphatases catalyze the hydrolytic fission of orthophosphoric acid ester. They are generally divided into acid and alkaline phosphatases according to their pH optimum. There was preparated the extract of leaves Nicotiana tabacum L. and Pissum sativum. Furthermore, there were determinated pea and tobacco phosphatases's rate constants. Reaction speed katalyzed by tobacco phosphatase is 10,0 mol/min.ml and by pea phosphatase 38,0 mol/min.ml using paraNP - phosphate as a substrate. Using a substrate phospho - L serine the reaction speed katalyzed by phosphatase of tobacco is 1,8 mol/min.ml and by phosphatase of pea is 0,4 mol/min.ml. Michaelis constant Km is 1,8 mM for tobacco phosphatase and 8,5 mM for pea phosphatase using paraNP - phosphate. Using a substrate phospho - L serine Michaelis constant Km of phosphatase of tobacco and pea is the same - 4,0 mM. The pH optimum of pea phosphatase is 5,0 using paraNP - phosphate as a substrate and 6,0 using phopho - L serine. pH optimum of tobacco phosphatase is 5,4 using paraNP - phosphate and 7,0 using phospho - L serine. Temperature optimum for pea phosphatase is 60 C and for tobacco phosphatase 55C.
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Control of lateral root development in response to availability of principal mineral nutrients.
Halamková, Daniela ; Tylová, Edita (advisor) ; Smetana, Ondřej (referee)
Lateral roots are, due to their large absorption surface, a part of the root system with significant importance for the plant's ingestion of water and nutrients. Their development depends on heterogeneity of soil environment, which enables the plant to optimize the acquisition of resources under current conditions. The availability of mineral nutrients (type of nutrient, form, distribution in soil and mobility) is one of key factors that determine root system morphogenesis. Another important aspect is the amount of nutrient in the plant; in other words, the plant's current demand for the element. The most important nutrients that influence the architecture of the root system are two macroelements - nitrogen and phosphorus. Both of these elements trigger positive and negative effects on the development of lateral roots. Nitrate, important source of nitrogen, induces two entirely different regulatory mechanisms of lateral root development. Under nitrogen limiting condition, a local stimulation of lateral root elongation is triggered in nitrate-rich patches. This response integrates the signalling pathways of auxin and nitrate. In contrast, high and homogenous availability of nitrate in rhizosphere (≥ 10 mM) causes inhibition of lateral root growth. This systemic inhibitory effect was similarly...
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