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Fungal root symbionts of the seagrasses Posidonia oceanica (Posidoniaceae) and Thalassodendron ciliatum (Cymodoceaceae)
Soperová, Beáta ; Vohník, Martin (advisor) ; Mrnka, Libor (referee)
Seagrasses form an important part of the marine vegetation and its growth create a habitat for many other organisms. Equal to the terrestrial plants, seagrasses can associate with various fungal species ranging from the parasitic to the endophytic ones. Posidonia oceanica and Thalassodendron ciliatum, whose ontogenetic development are very similar, are considered to be the ones of the best studied seagrass. Seedlings of both species have a primary root densely covered with root hairs, which is later replaced by secondary roots. In the vast majority of cases, the adult P. oceanica and T. ciliatum do not form root hairs on the secondary roots. In the case of P. oceanica, this transition from roots with root hairs to roots lacking root hairs appears to be associated with interaction with endophytic fungi. The incidence of interaction with endophytic fungi is still unclear for T. ciliatum. A summary of existing knowledge of the root hairs and fungal root symbionts of P. oceanica and T. ciliatum has revealed an incomplete knowledge of the effect of endophytic fungi on roots and root hairs formation in P. oceanica and a complete absence of studies of T. ciliatum mycobionts. The summary has further led to the hypothesis of possible coevolution of endophytic fungi and seagrass P. oceanica.
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Change of structure and function of a fungal comunnities in the soil environment after the end of the flowassimilates with Norway spruce (Picea abies)
Charvátová, Markéta ; Baldrian, Petr (advisor) ; Mrnka, Libor (referee)
The decomposition of plant biomass is associated with changes of the associated fungal community which is crucial in the process of degradation due to their production of extracellular enzymes. Moreover, fungal communities as well as enzymatic activity are specific for soil microhabitats. This thesis focused on the importance of fungi associated with the roots of Norway spruce (Picea abies) trees. Forest with dominating Norway spruce, located in the School Forest Enterprise Křtiny area in Moravia, was selected for the experiment. The aim of this thesis was to compare the community composition of fungi in the roots, rhizosphere and bulk soil and to describe the gradual development of this community after the death of the roots. The next aim was to isolate, describe and characterize those fungi that decomposed roots 5 and 9 months after tree harvest. Identification of fungal isolates was based on DNA sequencing. Degradation capabilities were determined as the activity of enzymes involved in the degradation of lignocellulose. Composition of fungal communities was described by sequencing of environmental DNA on the Illumina platform. Before the flow of assimilates from the live trees stopped, communities of ectomycorrhizal fungi dominated with 60 % of all sequences. Increased abundance of saprotrophic...
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The role of DSE (Dark Septate Endophytes) in plant communities in forest ecosystem
Lukešová, Tereza ; Vohník, Martin (advisor) ; Mrnka, Libor (referee)
10 Abstract All plants live in symbiosis with fungal endophytes - they can form mutualistic, commensal or parasitic symbioses. Symbiosis of root endophytes, called for their darkly pigmented and septated hyphae dark septate endophytes (DSE), and plants has been often overlooked although its role for plant communities can be very important. Despite their ubiquitous presence in roots of terrestrial and also aquatic plants the influence of DSE on their host plants is still unresolved. Results of previous studies are inconsistent - some reported that DSE have positive effects on their host plant growth and some negative. The main reason for this inconsistency might be their complicated taxonomy and difficult identification of different cryptic species which are morphologically indistinguishable. We were able to complete a unique collection of the most common DSE species, mainly members of the Phialocephala fortinii - Acephala applanata species complex. The collection includes the most common DSE species isolated from roots of forest plant communities. The goal of my thesis was to describe behaviour of DSE in roots of typical forest plants and elucidate their physiological influence on host plants. In vitro resynthesis experiments were used to observe root colonization patterns. Nutrient flow between the plant...
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Vliv duální mykorhizy na příjem těžkých kovů vybranými dřevinami čeledi Salicaceae
Kuchár, Michal ; Mrnka, Libor (advisor) ; Kolaříková, Zuzana (referee)
3.2. Abstract Soil contamination by heavy metals represents rather serious environmental problem for both human health and an environment itself. One of the perspective technologies dealing with this threat that only recently has been intensely developed is phytoremediation by means of short rotation coppice plantations. As plants used in this technology (mostly poplars and willows) host two major groups of mycorrhizal fungi substantially influencing plant physiology it is important to study plant-mycobiontheavy metals interactions rather than just plant-heavy metals interactions. The present thesis aimed to contribute to the growing knowledge of the field by search for suitable mycobionts of poplar or willow tolerant to heavy metals, by evaluating an activity of the key antioxidative enzyme in selected mycobionts and by looking at physiological responses of plant hosts to their mycobionts in a soil polluted by heavy metals. The first experiment in vitro focused on screening of morphometric criteria of fungi growing on solid growth media amended with mixture of heavy metals. Based on the results, several tolerant ectomycorrhizal strains were chosen for the next inoculation of fast growing trees serving phytoextraction and phytostabilisation strategies. The second, re-synthetic experiment was conducted in...
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Utilization of endophytic microorganisms for growth promotion of Miscanthus
Mrnka, Libor ; Frantík, Tomáš ; Schmidt, Christoph Stephan ; Lovecká, P.
Increased survival and aboveground biomass yield of Miscanthus was achieved due to the inoculation of Miscanthus seedlings by a mixed inocula based on the selected endophytic microbes (bacteria and fungi). Inoculated treatments produced 20-90% higher yield of biomass compared to the controls. Importantly, fungal inoculum increased also production of rhizomes and the same trend was observed in the treatment inoculated by the bacterial mixture. Bacterial endophytes also strongly augmented overwintering of the plants on one of the tested model plantations. Because the price of the inocula production is economically feasible and does not substantially increase the plantation establishment costs we hope for fast implementation of the methodology both in CR and beyond.
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Use of sewage sludge and biomass ash as a fertilizer of short-rotation coppice plantations
Mrnka, Libor
Cultivation of short-rotation coppice (SRC) plantations is gaining momentum with the increasing demand for renewable energy worldwide. Even the modest nutrient demands of SRC plantations deplete the soil nutrient pool over time and sustainable long- term production requires application of appropriate fertilizers. The waste products sewage sludge and biomass ash are complex fertilizers rich in nutrients. Yet their application in field is restricted due to an appreciable content of hazardous substances. In this manual we propose guidelines on the use of sewage sludge and biomass ash as a main fertilizer of SRC plantations. Our manual complies with all laws that regulate the use of the waste on agricultural land in the Czech Republic. It specifies application mode and time. Dosages are calculated based on the local soil conditions, the leaf nutrient status and the genotype of the used tree clones. Simple calculations use derived table values and allow the grower to assess the fertilization needs of a particular plantation and the way how to meet them very quickly. The manual has been certified by the Ministry of Agriculture of the Czech Republic.
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