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How does mycorrhiza protect the plant against phytoparasitic nematode Meloidogyne incognita?
Novák, Václav ; Janoušková, Martina (advisor) ; Řezáčová, Veronika (referee)
The nematode species Meloidogyne incognita is an important plant endoparasite. The infectious developmental stage infects plant roots in the soil to form pathological morphological formations - galls. The most widely used means of protecting crops from nematode infestation are chemical agents, nematocides. However, in order to reduce the negative impact on the environment, emphasis is being placed on finding new, sustainable solutions to combat the parasites. One of these could be to exploit the benefits of arbuscular mycorrhizae (AM), which include increased protection of plants against biotic stresses. This may be due, in addition to improved nutrient availability (especially phosphorus), to the induction of a systemic defence response, or to the interaction of AM fungi with other organisms in the rhizosphere. The main objective of this study was to describe the effect of AM on the resistance of tomato (Solanum lycopersicum) to root parasite, the nematode Meloidogyne incognita. In three containerized greenhouse experiment the following was tested 1) the nutrient conditions for tomato cultivation with mycorrhiza, then 2) the effect of nematodes on growth and nutrient uptake by experimental plants, the interaction between nematodes and AM fungi in the root system, and 3) the effect of root...
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Plant-soil feedback as a mechanism affect species diverzity of communities
Vondráková, Zuzana ; Münzbergová, Zuzana (advisor) ; Janoušková, Martina (referee)
Plant-soil feedback is known as the interaction between plant and soil. There is the feedback, when plant affect soil during their roots and on the other side soil affect growth and development through the change of their biotic and abiotic conditions. The plant-soil feedback is important mechanism of affecting plants or their competitive plant species through the soil. In this thesis I would like to summarize the functioning of the plant-soil feedback and factors which influence the feedback, the effect of feedback on the species diversity of plant communities, role in secondary succession, invasion and during coexistence of different species. I would like to point out, in which cases this feedback was confirmed experimentally and which experimental methods are used in the study of plant-soil feedback.
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Importance of arbuscular mycorrhizal fungal communities for the growth of selected plant species on an abandonned field
Voříšková, Alena ; Janoušková, Martina (advisor) ; Gryndler, Milan (referee)
The thesis deals with the effect of arbuscular mycorrhiza (AM) on the growth of selected plant species at a locality in České středohoří. This locality is characterized by close neighborhood of a semi-natural dry grassland and a former field abandonned in the 1990s, typical for the mosaic of biotopes in the region. The study is based on previous findings that some plant species, which are common at the semi-natural dry grasslands, do not colonize the abandoned fields. As AM is an important factor affecting diversity and productivity of plant communities we hypothesized that this phenomenon could be related to changes in AM fungal communities at the abandoned field. The hyphothesis was tested in a greenhouse pot experiment with three taxonomically related pairs of plant species, always one species growing at the abandoned field and the second one not. Growth and phosphorus uptake of the plants was followed in soils of both biotopes after factorial inoculation with AM fungal communities from both biotopes. The experiment was complemented by description of AM fungal communities in the roots of six plant species pairs from the locality using terminal restriction fragment length polymorphism (T-RFLP). The greenhouse experiment revealed positive mycorrhizal response in all plant species, but the origin...
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Specificity between partners in arbuscular mycorrhizal symbiosis
Voříšková, Alena ; Janoušková, Martina (advisor) ; Püschel, David (referee)
Arbuscular mycorrhiza (AM) is a symbiotic interaction between vascular plants and arbuscular mycorrhizal fungi from phylum Glomeromycota. AM symbiosis is considered as a nonspecific interaction, because AM fungi are able to colonize roots of all plant species which are hosts for this type of symbiosis, nevertheless certain specific interactions exist between the partners. The specificity can be evident on the level of the formation of mycorrhiza, which means that different species of plants can vary in the composition of fungal community in their roots or AM fungi can differ in an ability of colonization and sporulation depending on host plant species. The specificity can also manifest as different functionality of the symbiosis in dependence on the particular partners affecting the mycorrhizal response of the host plants. All of these specific interactions can have an impact on the coexistence and diversity of plants in communities.
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The importance of time, space and genotype for the intensity of plant-soil feedback
Vondráková, Zuzana ; Münzbergová, Zuzana (advisor) ; Janoušková, Martina (referee)
Plant-soil feedback is an important mechanism in plant communities affecting their species composition. Understanding plant-soil feedback is crucial for describing the interactions between plant communities and their soil communities. The effects of plant-soil feedback can be positive, negative or neutral and because of these changes plants are either coexisting or competing. Plant-soil feedback is often studied within plant succession, plant invasion and plant dominance in a plant community. In these cases, the nature and strength of influence of each species is studied. Despite the large number of previous studies on plant-soil feedback, very little is known about the temporal and spatial changes of the intensity of plant-soil feedback and the intraspecific variability in plant-soil feedback. The aim of my work was to observe the temporal changes in the plant-soil feedback of a species growing in soil which was conditioned by the same or other plant species. Another goal was to explore spatial changes in plant-soil feedback. The last objective was to test differences in the intensity of plant-soil feedback among different genotypes of one species. The results of my work demonstrated that the intensity of intraspecific plant-soil feedback of Rorippa austriaca is negative and increases with...
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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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Life history strategies of arbuscular mycorrhizal fungi
Fričová, Renata ; Janoušková, Martina (advisor) ; Kohout, Petr (referee)
Arbuscular mycorrhiza is a symbiotic interaction of vascular plants and arbuscular mycorrhizal (AM) fungi from subphylum Glomeromycotina. Currently, it is difficult to predict the population dynamics of AM fungal communities, mainly because little is known about their life-history strategies. However, it is clear that AM fungi differ in a range of traits. Physiological and ecological differences between AM fungi can affect the outcome of their competition as well as cooperation with the plant symbiont and the successional dynamics of the whole community. In order to advance our knowledge of AM fungal life-history strategies, it is crucial to deepen our understanding of the traits and factors that modify interactions between the symbionts. This bachelor thesis is designed as a literature survey aimed at summarizing knowledge about functional traits of AM fungi and the impact of these traits on their life-history strategies. Key words: arbuscular mycorrhizal fungi, life-history strategies, host plant, traits, mycelium, colonization, competition, community, succession
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Contribution of arbuscular mycorrhiza to ecosystem services in agroecosystems
Šabatková, Zuzana ; Janoušková, Martina (advisor) ; Kohout, Petr (referee)
Arbuscular mycorrhizal fungi are significant plant mutualists providing their host plants with many benefits. For efficient use of arbuscular mycorrhiza in agricultural systems, it is important to understand factors, which can influence the beneficial effects of the symbiosis, and how arbuscular mycorrhizal fungi alter plant physiological mechanisms. If used correctly, arbuscular mycorrhizal fungi could importantly contribute to various ecosystem services in agroecosystems and thus alleviate yield losses and decrease the negative impact of agriculture on ecosystems. This thesis summarizes the impact of arbuscular mycorrhizal fungi on crop plants in agroecosystems, their occurence in agricultural systems, particularly in arable soils, as well as their contribution to selected ecosystem services in agroecosystems. Key words: arbuscular mycorrhizal fungi, ecosystem services, agroecosystem, soil formation, environmental stress, plant resistence
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