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Mechanisms of physical dormancy and germination of orchid seeds
Jiroušková, Anna ; Ponert, Jan (advisor) ; Vosolsobě, Stanislav (referee)
Orchid seeds are called dust seeds because of very reduced structure. A mature dust seed is composed of living embryo and two seed coats which are formed by dead cells. While the outer seed coat is distinctive, the inner seed coat (known as carapace) is very thin and tightly surrounds the embryo. Seed coat is hydrophobic and prevents water from entering embryo. To induce germination artificially, calcium hypochlorite or sodium hypochlorite solutions are often used. However, the effect of chemical scarification on seed coats is poorly understood. I focused on seeds of Epipactis helleborine and Dactylorhiza majalis and I analysed changes in seeds induced by calcium hypochlorite treatment using germination of seeds in vitro, permeability tests of seed coats and histochemical analyses of selected components of seed coats. The most prominent change observed was decrease of amount of lignin in the outer seed coat. This is likely related to increase in permeability of seeds and stimulation of in vitro germination rate in Dactylorhiza majalis which has only thin and less complex inner seed coat. However, this relationship was less evident in Epipactis helleborine, which has thicker and more complex inner seed coat which is more resistant to hypochlorite scarification. This could indicate existence of...
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The importance of mycorrhizal fungi in primary succession
Nevěčná, Michaela ; Münzbergová, Zuzana (advisor) ; Püschel, David (referee)
Primary succession is a relatively long-term process of colonization of a certain area, which has never been influenced by any biotic environmental elements. There are many factors that influence primary succession. One of them are mycorrhizal fungi. Establishment of mycorrhizal symbiosis, i. e. a mutualistic relationship between plants and mycorrhizal fungi, can be an important factor facilitating development of vegetation cover. Plants profit from mycorrhizal symbiosis thanks to increased nutrient acquisition, protection against toxic heavy metals or an advantage in a competition with non-mycorrhizal plants. Being non-photosynthetic organisms, fungi gain assimilates from the plants. Modification of the course of primary succession by adding mycorrhizal fungi can have a big importance in reclamation of the areas damaged by mining and there is a potential to substitute, at least partly, technical reclamations.
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Ericaceae root mycobionts: diversity, distribution and interactions with neighboring plants
Kolátková, Viktorie ; Vohník, Martin (advisor) ; Baláž, Milan (referee)
The roots of ericaceous plants provide an environment to many fungal endophytes and mycorrhizal fungi.We can observe at least four mycorrhizal types in the family, of which the ericoid mycorrhiza (ErM) is spread the most. The Ericaceae are able to survive in many different and often harsh habitats all over the world thanks to this symbiosis (from the tropical cloud forests, to the arctic tundra heathlands). The group of fungi, forming this relationship, used to be seen as a few very well circumscribed ascomycetes, namely Rhizoscyphus ericae (Read) Zhang & Zhuang and Oidiodendron maius Barron species. With the development of molecular methods, it was expanded of many other species, some of which belonging to Basidiomycota, particularly the order Sebacinales. The diversity of ErM fungal community varies at different geographic locations and it can be influenced by factors such as altitude or the surrounding ecosystem. However, due to lack of further information, we still know quite little about the species distribution. Although they are primarily symbionts of the Ericaceae, some ErM fungi can colonize wider spectrum of plant hosts. Their effect on these hosts is not yet fully understood. Most importantly, they increase the vitality of ericaceous plants and favor them in competition with adjacent...
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The importance of mycorrhizal fungi in the root decomposition.
Haiclová, Klára ; Kohout, Petr (advisor) ; Kolaříková, Zuzana (referee)
Mycorrhizal fungi are known as symbionts of many plant species. Fungi provide better access to mineral nutrients and water for host plants, and in return fungi receive carbohydrates from plants. Although a significant proportion of organic matter is bound in the root biomass, little is known about the factors affecting root decomposition. Understanding the process of root decomposition and the factors that affect it, is important to us. Knowledge of root decomposition helps us understand the carbon cycle and answer questions about carbon sequestration in soil. This Bachelor's thesis is focused on the importance and function of mycorrhizal fungi during root decomposition. It describes the influence of mycorrhizal fungi on the decomposition of fine roots colonized by mycorrhizae, the ability of mycorrhizal fungi to decompose organic matter and influence the decomposition rate through competition with saprotrophic organisms. Keywords: mycorrhizal fungi, roots, decomposition, rate, organic matter, soil, importance, carbon sequestration
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Interactions of initially mycoheterotrophic plants with environment
Figura, Tomáš ; Ponert, Jan (advisor) ; Kolařík, Miroslav (referee) ; Janoušková, Martina (referee)
Initially mycoheterotrophic plants have recently been declining in the wild, even without apparent causes. They are affected by a number of biotic and abiotic factors. The aim of this work is to investigate how selected factors, such as nitrate or symbiotic fungi, may influence their distribution in nature. In particular, the work applies in vitro experiments, molecular determination of fungal symbionts and stable isotope analyses. It describes both the effects of abiotic factor, specifically nitrate, and biotic interactions of initially mycoheterotrophic plants with fungal symbionts. The inhibition of germination by extremely low concentrations of nitrate in asymbiotic in vitro cultures was observed in several orchid species. The degree of sensitivity of each species to nitrate corresponds with the nitrate content of the soil and the nutrient availability requirements of the species according to Ellenberg indicator values. The inhibitory effect of nitrate on orchid germination was also observed in symbiotic in vitro cultures. Out of five tested fungal strains, only one Ceratobasidium was capable of eliminating the inhibitory effect of nitrate. Furthermore, the work reveals that green mixotrophic orchids use photosynthates to nourish the aboveground parts, whereas the belowground parts are...
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Mycorrhizal fungal diversity along altitudinal gradients
Schultzová, Pavlína ; Kohout, Petr (advisor) ; Mašínová, Tereza (referee)
Mycorrhizal symbiosis is an integral component of all terrestrial ecosystems and the most widespread mutualistic association in the world. Nevertheless, our current knowledge regarding diversity patterns of mycorrhizal fungi along altitudinal gradients is considerably limited. Published studies to date suggest either a decrease in mycorrhizal fungal diversity with increasing elevation or a hump-shaped pattern, similar to the general altitudinal diversity patterns that have been observed in macroorganisms. Lower mycorrhizal fungal diversity at higher elevations in some regions may significantly impact host plants migrating upward due to global warming. Therefore, insights into the shifts in mycorrhizal fungal distribution along elevational gradients can provide better predictions of future effects of climate change on mycorrhizal fungi and host plants. In order to advance our knowledge of mycorrhizal fungal diversity, it is crucial to deepen our understanding of the factors that shape mycorrhizal fungal responses along altitudinal gradients.
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The importance of mycorrhizal fungi in the root decomposition.
Haiclová, Klára ; Kohout, Petr (advisor) ; Kolaříková, Zuzana (referee)
Mycorrhizal fungi are known as symbionts of many plant species. Fungi provide better access to mineral nutrients and water for host plants, and in return fungi receive carbohydrates from plants. Although a significant proportion of organic matter is bound in the root biomass, little is known about the factors affecting root decomposition. Understanding the process of root decomposition and the factors that affect it, is important to us. Knowledge of root decomposition helps us understand the carbon cycle and answer questions about carbon sequestration in soil. This Bachelor's thesis is focused on the importance and function of mycorrhizal fungi during root decomposition. It describes the influence of mycorrhizal fungi on the decomposition of fine roots colonized by mycorrhizae, the ability of mycorrhizal fungi to decompose organic matter and influence the decomposition rate through competition with saprotrophic organisms. Keywords: mycorrhizal fungi, roots, decomposition, rate, organic matter, soil, importance, carbon sequestration
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Ericaceae root mycobionts: diversity, distribution and interactions with neighboring plants
Kolátková, Viktorie ; Vohník, Martin (advisor) ; Baláž, Milan (referee)
The roots of ericaceous plants provide an environment to many fungal endophytes and mycorrhizal fungi.We can observe at least four mycorrhizal types in the family, of which the ericoid mycorrhiza (ErM) is spread the most. The Ericaceae are able to survive in many different and often harsh habitats all over the world thanks to this symbiosis (from the tropical cloud forests, to the arctic tundra heathlands). The group of fungi, forming this relationship, used to be seen as a few very well circumscribed ascomycetes, namely Rhizoscyphus ericae (Read) Zhang & Zhuang and Oidiodendron maius Barron species. With the development of molecular methods, it was expanded of many other species, some of which belonging to Basidiomycota, particularly the order Sebacinales. The diversity of ErM fungal community varies at different geographic locations and it can be influenced by factors such as altitude or the surrounding ecosystem. However, due to lack of further information, we still know quite little about the species distribution. Although they are primarily symbionts of the Ericaceae, some ErM fungi can colonize wider spectrum of plant hosts. Their effect on these hosts is not yet fully understood. Most importantly, they increase the vitality of ericaceous plants and favor them in competition with adjacent...
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The importance of mycorrhizal fungi in primary succession
Nevěčná, Michaela ; Münzbergová, Zuzana (advisor) ; Püschel, David (referee)
Primary succession is a relatively long-term process of colonization of a certain area, which has never been influenced by any biotic environmental elements. There are many factors that influence primary succession. One of them are mycorrhizal fungi. Establishment of mycorrhizal symbiosis, i. e. a mutualistic relationship between plants and mycorrhizal fungi, can be an important factor facilitating development of vegetation cover. Plants profit from mycorrhizal symbiosis thanks to increased nutrient acquisition, protection against toxic heavy metals or an advantage in a competition with non-mycorrhizal plants. Being non-photosynthetic organisms, fungi gain assimilates from the plants. Modification of the course of primary succession by adding mycorrhizal fungi can have a big importance in reclamation of the areas damaged by mining and there is a potential to substitute, at least partly, technical reclamations.
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Význam mykorhizních hub při tvorbě půdní struktury
Čevelová, Lucie
The essence of this bachelor thesis is become with diffrent groups of mycorrhizal fungi, which support the formation of soil structure. Plants along with mycorrhizal fungi form symbiotic relationship that is beneficial for both partners. Thanks to this the plant receives vital nutrients and protected agains pathogens. Moreover the mycorrhizal fungi involved in the formation of the soil structure. The mycelium intergrows through the soil aggregates and provides mechanical stabilization of the soil. Fungi of the arbuscular mycorrhizal symbiosis produce the glycoprotein glomalin, which stabilizes the soil structure. To support the growth of mycorrhizal fungi in the soil, we follow right agriculture methods. We can also use the application of the vaccination preparation or additing biochar and other inorganic materials into the soil.
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