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The importance of root exudates for crop cultivation under climate change
Schnürer, Oliver ; Albrechtová, Jana (advisor) ; Tylová, Edita (referee)
Root exudates are compounds secreted by plant roots that can help plants, for example, to obtain nutrients from the soil or to increase their resistance to biotic stress. Root exudates can thus hide a great potential that can be used in agriculture. As human population grows, there is increasing pressure on agriculture, which must provide enough food to feed the global population, thus ensuring food security. Until now, agricultural activity has tried to satisfy this demand by intensification of agriculture, mainly by breeding highly productive crops when using intensive fertilizing, but the theoretical possible benefits of root exudates in breeding remained overlooked. Intensive farming practices can further exacerbate the impacts of ongoing climate change, for example by increasing soil carbon mineralization or reducing biodiversity. By using root exudates in the production of crops, it will be possible to achieve a higher nutrient content in soil, as well as a higher resistance of crops to pests, without the aforementioned negative impacts of intensive agriculture. In this work, I tried to describe the main functions of root exudates, their reaction to increased CO2 concentration in the atmosphere, their stress response caused by stressors of climate change and their theoretical use in...
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Uptake of heavy metals - the role of the root system
Homola, Adam ; Tylová, Edita (advisor) ; Mašková, Petra (referee)
Heavy metals are important soil pollutants and pose a significant risk to plants under certain conditions. These include some essential microelements (Fe, Zn, Mn, Mo, Cu, Ni) and toxic metals (e.g. Cd, As, Pb, Hg). Essential microelements have important functions in plants, and are mainly involved in plant metabolism as cofactors of enzymes. Toxic metals have no function, yet they enter the plant in varying degrees from the environment and cause toxicity. However, excessive concentrations of essential metals in the plant also have negative effects and plants have different mechanisms to counteract these negative effects. The bachelor thesis focuses mainly on the uptake of heavy metals from the soil by the root, which is achieved by membrane transporters. It also discusses several mechanisms involved in defence against heavy metal toxicity, not only in terms of regulating uptake, but also after heavy metals have entered plant bodies. These mechanisms are an important aspect of hyperaccumulation, which is also included in this thesis. Hyperaccumulators use these mechanisms on a completely different scale than non-hyperaccumulators, which allows hyperaccumulators to live in environments where heavy metal concentrations are high, making them completely different from each other. The properties of...
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Relationship between leaf biochemistry, physiology and specie's competitiveness in selected grasses of relict tundra in Krkonoše Mts.
Mamula, Petr Martin ; Lhotáková, Zuzana (advisor) ; Tylová, Edita (referee)
The Krkonoše (Giant Mountains) Arcto-Alpine Tundra is an area that is part of the Krkonoše National Park with a unique ecosystem and biodiversity. In history, this area was very fundamentally influenced by the intervention of man, who farmed here and thus caused the creation of today's rare matgrass (Nardus stricta L.) meadow ecosystem. Thanks to the low growth and sparse foliage of the matgrass, many other plant species grow in these matgrass meadows, which are often endemic and protected by the law. In recent years, however, the matgrass has been overgrown by other grasses, such as the hairy reed grass (Calamagrostis villosa J.F. Gmelin), which, due to its taller growth and dense canopy covering the surface, does not allow the growth of rare species such as matgrass. Therefore, the aim of this work was for matgrass (N. stricta) and three other selected species of grasses - tufted hair grass (Deschampsia cespitosa (L.) P. Beauv.), moor grass (Molinia caerulea (L.) Moench) and hairy reed grass (C. villosa), to identify, based on biochemical, structural and physiological foliar parameters, a parameter or a combination of parameters that could give competing fennel grasses a competitive advantage. Field research and collection of foliage samples, for subsequent laboratory processing, took place in...
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Cell biology of iron transport in plants.
Batík, Adam ; Žárský, Viktor (advisor) ; Tylová, Edita (referee)
Plants use iron as a cofactor of proteins used in photosynthetic systems, electron transport chain and many more. Iron bioavailability for plants in soil is low because it tends to oxidise and create insoluable compounds.For this reasonplants haveevolvedtwo distinct iron uptake mechanisms.Because of the iron toxicitycaused by production ofreactiveoxygen species via the Fenton reaction and the unspecific transport of metals other than iron, plants have to regulate cellular iron concentrationtightly.Theyhave evolved a complex system of signalling networks that has recently begun to uncover. In additionto the regulation ofiron uptake, the plant cell combats iron toxicity by sequestering iron into storage organelles and by chelating it. Iron is essential for seed sprouting but this work is focused on transport of iron into the plant from the soil,subcellulartransportandlongdistance transport ofironin the vasculature.
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Ecophysiological relevance of extreme sensitivity of orchids to nitrates
Figura, Tomáš ; Ponert, Jan (advisor) ; Tylová, Edita (referee)
Many orchid species are seriously endangered at present. Reasons for their disappearing from natural habitats remain often unclear. Orchids depend on mycorrhizal symbiosis in nature, however only little is known about this symbiosis. Seeds of some species do not germinate in vitro, making their cultivation for scientific and rescue purposes impossible. We found that seed germination of one of such reluctant species, Pseudorchis albida, is strongly inhibited by nitrates even at extremely low concentrations. As this species prefers oligotrophic mountain meadows, nitrate-induced inhibition probably take place in natural conditions. Surprisingly, we found similar but slightly weaker inhibitory effect also in typical mesophillic species and even in slightly eutrophic ones. The sensitivity to nitrates correlates with trophy level of species canopy. This inhibitory effect of nitrates could be weakened by application of a range of growth regulators, including auxins, cytokinins and gibberellins, and also by mycorrhizal fungi. The action of nitratereductase is essential for this inhibitory effect of nitrates. Experiments with NO donors, scavengers, and NO quantification are pointing right at NO as compound which perhaps mediates nitrate inhibitory effect. Based on these results, the nitrate inhibitory...
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Variability and mechanisms of exodermis differentiation in plant roots
Blascheová, Zuzana ; Tylová, Edita (advisor) ; Konrádová, Hana (referee)
Environmental conditions affect the formation of apoplastic barriers (endodermis and exodermis) in roots. This was shown on many species in many research papers. The exodermal layer is more variable in response to stress conditions than endodermal layer. Cadmium toxicity, as many other stresses, induces faster development of apoplastic barriers. Most of research papers published so far, however characterized only the response of main root to this type of stress factor. Lateral roots, an important part of the root system absorptive surface, are neglected and there is not much information about their response to cadmium stress. The pattern of apoplastic barriers development was therefore analysed in main and also in lateral roots of various size and position on maternal root axis. We found significant differences in response to cadmium stress among these different root types. Then we summed up the differences between these types of roots. Short lateral roots were generally more responsive to cadmium stress, cadmium affected root branching as well as differentiation of apoplastic barriers in lateral roots. These results help us to better understand the response of complex roots system to environmental conditions. In the second part of this work, the role of CASP genes in exodermal development was...
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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...
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Lateral root development in response to mineral nutrients; signal mechanisms and pathways.
Halamková, Daniela ; Tylová, Edita (advisor) ; Lhotáková, Zuzana (referee)
TTL3 gene was identified by forward screening of genes involved in lateral root development in Arabidopsis thaliana based on its expression pattern. TTL3 belongs to the TTL (TETRATRICOPEPTIDE-REPEAT THIOREDOXIN-LIKE) gene family. The diploma thesis is aimed on characterisation of changes in TTL1, TTL3 a TTL4 promotor activities in response to external conditions (availability of nitrogen or phosphorus) that affect root growth. Obtained data should elucidate possible relation among TTL gene expression activities, root growth rate, and apical meristem activity. Nitrogen or phosphorus deficiency triggered changes in root growth and root system morphology of experimental plants. Short-term nitrogen deficiency stimulated root growth. Short-term phosphorus deficiency induced gradual growth cessation in main root and long laterals. Long-term deficiency reduced root growth of both N-deficient and P-deficient plants compared to control. The root system size of N-deficient and P-deficient plant was almost similar. Determination of promotor activity using β-glucuronidase reporter gene showed changes in expression activity and its localization in response to root growth intensity. TTL4 gene promotor activity was the most responsive. Its activity was generally higher in slowly growing roots, particularly under...
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Lignin and lignification mechanisms
Gargoš, Ondřej ; Tylová, Edita (advisor) ; Schwarzerová, Kateřina (referee)
Lignin is an essential compound of all vascular plants. Recent studies have also shown its presence in non-vascular plants. Lignin is important for plant growth and development, provides a mechanical support to plant tissues and is also a major player in the response of plants to various stresses. Lignin is an aromatic heteropolymer and comprises classical lignin units - guaiacyl (G), syringyl (S) and p-hydroxyfenyl (H). The amount and ratio of these lignin units varies among plant species, organs and cell types. Nontraditional monomer units that can be deposited in lignin also increase the variety of lignin. Lignification, i.e. the formation and deposition of lignin, is a complex and precisely controlled process involving the synthesis of monolignols in the cytoplasm, their transport into the cell wall and subsequent polymerization. A number of enzymes are involved in the lignification process, and recent studies are gradually revealing the mechanisms of lignification regulation in various cells of plant body. This bachelor thesis summarizes the knowledge of the importance, synthesis and deposition of lignin, and also compares the mechanisms regulating lignification in different types of plant cells - tracheary elements, sclerenchyma and endodermal cells. An interesting phenomenon of lignification...
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