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Variability in the response of exodermis to nutrient deficiencies in the environment
Klvaňová, Renáta ; Tylová, Edita (advisor) ; Konrádová, Hana (referee)
v angličtině Plant growth and development is largely dependent on the soil environment which is a source of minerals and water needed for plants to survive. However, the availability of these resources in the soil is very heterogenous and important elements can be leached into the lower parts of the soil or bound to soil particles. Plants have therefore developed a number of adaptations during evolution to increase the efficiency of the root system. One of these aspects are the apoplastic barriers (endodermis and exodermis). Both of these layers affect the transport of substances to and from the root, thereby limiting unregulated apoplastic transport through modifications of the cell walls where the polymers that limit the transport of substances are deposited. These are Casparian bands and suberin lamellae. They often differentiate more rapidly when plants are faced with a stress factor such as drought, salinity or toxicity. However, nutrient deficiencies (e.g. N, P, K and Fe) also affect the rate of differentation. Deficiencies can result in both acceleration and deceleration of differentation, which seems to help optimize root transport properties according to the current conditions. However, this reaction has been less studied so far. This work therefore focuses on the analysis of the response...
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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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Mechanisms of exodermal response to nutrient availability in the environment
Gargoš, Ondřej ; Tylová, Edita (advisor) ; Kummerová, Marie (referee)
in English The apoplastic barriers of the root (endodermis and exodermis) represent an important regulatory mechanism for the uptake of water and nutrients from the environment, ensuring its selectivity. In addition, both layers respond to stress factors by altering its rate and degree of cell wall modification, which affects the transport properties of the root and represents adaptive plants to high heterogeneity of the soil environment. Apoplastic barriers also respond to the availability of mineral nutrients. This issue has recently been intensively studied and a number of ambiguities persist. Interestingly, the deficiency of some mineral nutrients stimulates the differentiation of barriers, while the deficiency of other mineral nutrients delays the differentiation. In addition, different plant species react differently to the deficiency of the same element. Another interesting aspect is the fact that the reaction of the endodermis and exodermis is localized and takes place mainly in that part of the root system which is directly exposed to the stress factor. This phenomenon has been observed with cadmium toxicity, but more recently with local nutrient deficiencies (nitrogen and potassium) in Zea mays. This diploma thesis deals with the functional significance of localized enhancing or delaying...
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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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Potassium deficiency in plants - signs and responses
Štočková, Hana ; Tylová, Edita (advisor) ; Konrádová, Hana (referee)
Plants receive K+ mainly from the soil through the root system. In soil, K+ occurs primarily in minerals such as mica and potassium feldspar. The availability of K+ for plant uptake depends on the form in which K+ occurs in soil. There are forms directly available, slowly available, and unavailable for plant and the transition of K+ between these pools may occur. In plant, K+ is very mobile and it occurs in high amount in cells. It is the most prominent cytoplasmic cation. It affects high number of metabolic processes, including photosynthesis, osmoregulation, and activation of enzymes. K+ shortage can cause changes in plant morphology, anatomy and metabolism. K+ deficiency can be manifested by leaf deformation, decreased leaf area, necrosis, short internodes, reduced rate of photosynthesis, etc. K+ deficient plant is also more vulnerable to pathogens and its resistance to abiotic stress factors such as drought, low temperatures, or salinity is decreased. Deficiency of K+ reduces the biomass and overall yield in agricultural crops, so K+ fertilizers, both soil and foliar, are needed. The thesis focuses on the manifestations of K+ deficiency in plants and summarizes the recent findings on mechanisms of K+ deficiency perception and signal pathways leading to the response to this deficiency. Key...
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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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Zinek jako esenciální mikronutrient
Hádler, Tomáš
In the first part of these presented bachelor thesis are described general characteristics of zinc, it's occurence in enviroment and it's history. Next part described effect of this element on human health (specific health risks associated with its deficiency), transport and its general role in the metabolism, further discussed. There are summarized recommendations for zinc daily intake. A major part of this thesis is focused on the zinc content in various types of foods. A main part of the thesis is concerned with zinc deficiency and symptoms of zinc deficiency for the living organisms. The following part described selected foods and their zinc content. A very substantial part of the work is the possibility of fortification of foods with zinc, as well as supplementation. Last but not least, the zinc metabolism is described and it's availability for human body. Some analytical methods for the determination of zinc in food and other biological samples are described.
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