Orientador: Ian Castro-Gamboa / Banca: Isabele Rodrigues Nascimento / Banca: Flávia Talarico Saia / Resumo: A cada ano vem crescendo a busca por novas fontes de produtos naturais, na qual os micr o - organismos recebem uma grande atenção, sendo eles de extrema importância na descoberta de compostos bioativos e promissores a novos fármacos. Esse trabalho teve como foco o estudo de fungos filamentosos da rizo sfera de Senna spectabilis . F oram testadas suas viabilid ad es e a pós esse processo, dez fungos foram escolhidos para esse trabalho e submetidos a os testes biológicos como citotóxico, anti colinesterásico e antifúngico e t ambém foram obtidos seus perfis cromatográficos e químicos por CLAE - DAD e RMN, além da identificação filogenética. A pós esses resultados iniciais, dois fungos foram escolhidos para desenvolver o método de desreplicação, sendo eles Fusarium solani e F . oxysporum . Esses fungos apresentaram atividade antifúngica contra C. cladosporioides e C. sphaerospermun e também apresentaram atividade anticolinesterásica, além disso, F. oxysporum apresentou também atividade antitumoral contra câncer do colorretal. Através das téc n icas CG - EM, CLAE - EM, CLAE - EM/EM e RMN foram propostas estruturas moleculares interessantes para substâncias produzidas por e sses micro - organismos, sendo que para o extrato de Fusarium solani foram identificados 1 2 metabólitos: ácido fumárico, ácido málico, tirosol, ácido p - hidroxibenzóico, ácido azelaico, ácido fusárico, ( - ) - ácido jasmônico/ácido (+) - 7 - iso - jasmônico, 10 - hidroxicaptotecina, C - 16 - esfinganina, xestoaminol C, armilarina/armilaripina e beauvericina e para o extrato d o fungo Fusarium oxysporum foram observados 14 metabólitos: ácido succínico, ácido p - hidroxibenzóico, ácido hexadecanó i co, ácido octadecanóico, ácido fusárico e três de seus derivados, integracídeo C, fusagerina C/D, C - 16 - esfinganina, xextoaminol C, armila rina/armilaripina e beauver i cina . Além desses... / Abstract: T he search for new sources of natural products has been increasing to the rational exploration of microorganisms as great sources for the discovery of bioactives and promising compounds as well as new drugs. This work focused on the study of filamentous fungi, isolated from Senna spectabilis's rhizosphere from which were tested its viabilities. Thereon, ten fungi were chosen for this work and were s ubmitted to biological tests, such as cytotoxic, anticholinesterase and antifungal. In addition, their chemical profiles were obtained for HPLC and NMR, besides phylogenetic identification. Finally, tw o fungi were chosen to develop dereplication method, being them Fusarium solani and F . oxysporum. Th ese fungi howed anticholinesterase activity and antifungal activity aga in st C. cladosporioides and C. sphaerospermun . Additionally, F. oxysporum showed antitumor activity against colorectal cancer. Through the GC - MS, HPLC - MS, HPLC - MS/MS and NMR, we were able to obtained interesting molecular chem o types for these microorganisms; for F. solani we identified 12 metabolites, fumaric acid, malic acid, tyrosol, p - hydroxybenzoic acid, azelaic acid, fusaric acid, (+) - 7 - iso - jasmonic acid/( - ) - jasmonic acid, 10 - hydroxycamptotecin, C16 - sphinganine, xestoaminol C, armillarin/armillaripin and beauvericin and for F. oxysporum was observed 14 metabolites, succinic acid, p - hydroxybenzoic acid, hexadecanoic acid, octadecanoic acid, fusaric acid and its three derivatives, integracide C, fusagerin C/D, C - 16 - sphinganine, xestoaminol C, armillarin/armillaripin and beauvericin . Besides these compounds, others 5 metabolites common to both species ( solani and ox y sporum ) couldn't be structurally characterized thorough LC - MS/MS, but they were accounted in several Fusarium species. / Mestre

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Objetivando avaliar o comportamento das emissões de CO2 do solo em áreas mineradas do município de Santo Antônio de Pádua-RJ e sua correlação com a rizosfera, este presente estudo utilizou uma câmara fechada com sensor de infravermelho em três diferentes paisagens, a saber: A-1 (área reflorestada há 10 anos), A-2 (área desmatada) e A-3 (área em processo de recuperação). Em cada área foi instalada três cilindros para efeitos de repetição. O monitoramento foi realizado durante os meses representativos de cada estação do ano de 2013, sendo a análise realizada durante dois dias consecutivos. Concomitantemente as coletas de CO2 foram realizadas coletas de dados de temperatura e umidade do solo, sendo também avaliadas informações pedológicas através das análises de granulometria, porosidade, pH, carbono orgânico e matéria orgânica. Informações meteorológicas e microclimatológicas também foram extraídas através de uma estação meteorológica automática e através de sensores portáteis. Os resultados permitem concluir que existe uma variação sazonal dos fluxos de CO2, havendo uma tendência de máximos de emissão durante o verão e de mínimas durante o inverno, sendo o outono e a primavera marcados por valores medianos. A correlação das áreas entre os dois dias monitoramento indicam que as emissões foram semelhantes ao da análise em dia anterior, apresentando uma correlação significativa a 5% para A-1 e A-2 e de 1% para A-3. A-1 e A-2 apresentaram emissões de CO2 mais homogêneas que A-3, havendo, entretanto, um maior fluxo de CO2 durante o verão para todas as áreas. Os dados de MOS, COS e pH demonstraram não haver uma correlação direta com as emissões de CO2. Os dados de porosidade e densidade, porém, apontam para uma possível correlação com as menores emissões de CO2 em A-3 devido a menor porosidade e maior densidade de seus solos. A temperatura do solo foi a variável que mais se correlacionou com as emissões de CO2, havendo um índice igual a r =0,68 para A-1 e de r =0,74 para A-2, sendo que em A-3 esta correlação não foi significativa. A temperatura do ar demonstrou uma correlação somente na área descampada de A-2. No que se refere à correlação da umidade do solo não houve correlações diretas significativas, sendo que somente houve uma correlação negativa (r=-0,50) significativa a 5% em A-3 com a umidade do ar. O diagnóstico ambiental das áreas de monitoramento revela que estas possuem baixos indicadores de qualidade, sendo afetados também pela escassez hídrica da região durante oito meses do ano. A-1 apresenta os melhores indicadores biológicos, químicos e microclimáticos, seguidos por A-2 e A-3 que apresentam diversas deficiências e problemas em termos de estrutura e atividade biológica dos solos. Neste estudo permite-se concluir que áreas próximas, porém com características distintas podem produzir diferentes padrões de emissão de CO2, dificultando, portanto, estimativas globais de emissão de CO2. Os elementos mais associados às emissões de CO2 parecem estar relacionados à temperatura do solo e do ar, umidade do ar e estrutura do solo, havendo, entretanto, outros fatores que podem estar indiretamente relacionados e que exercem diferentes influências de acordo com o ambiente analisado. / Seeking evaluate the performance of CO2 emissions from soil in mined areas in the municipality of Saint Anthony of Padua - RJ and its correlation with the rhizosphere , the present study used a closed chamber with infrared sensor in three different landscapes , namely: A- 1 ( reforested area 10 years ago ) , a- 2 ( pasture) and A- 3 (area under recovery ) . In each area was installed three cylinders for the purpose of repetition. Monitoring was conducted during the months representing each season of the year 2013, with an analysis performed for two consecutive days. Simultaneously the analyses of temperature and soil moisture were performed, and also evaluated soil information by analyzing particle size , porosity, pH , organic carbon and organic matter information microclimatológicas and of weather were also extracted through sensors automatic and portable.The results indicate that there is a seasonal variation in CO2 fluxes , there is a trend of maximum emission during summer and minimum during winter , with autumn and spring marked by median values . The correlation among the areas two days indicate that monitoring emissions analysis were similar to the previous days, presenting a significant correlation to 5 % for A -1 and A -2 and A- 1 to 3 %. A- 1 and A- 2 had CO2 emissions more homogeneous than A- 3, there are, however, a greater flow of CO2 during the summer for all areas. MOS data, COS and pH showed no direct correlation with CO2 emissions. The porosity and density data, however, point to a possible correlation with the lowest CO2 emissions in A- 3 due to lower porosity and higher density of your soil. Soil temperature was the variable that was most associated with CO2 emissions, with an equal index for air = 0.68 A- 1 and r = 0.74 for A- 2, and A- 3 in this correlation was not significant. The air temperature showed a correlation only in the open area A- 2. With regard to the correlation of soil moisture no significant direct correlations, and only there was a significant negative correlation (r = -0.50) to 5 % in A- 3 with the humidity. The environmental assessment of the areas of monitoring shows that these have low quality indicators is also affected by water shortages in the region for eight months of the year. A- 1 shows the best biological, chemical and microclimatic indicators, followed by A-2 and A- 3 which have several deficiencies and problems in terms of structure and biological activity of soil. In this study, we conclude that nearby areas , but with distinct characteristics can produce different patterns of CO2 emission , thus hindering global estimates of CO2 emissions . Most elements associated CO2 emissions appear to be related to soil temperature and air temperature , humidity and soil , however , other factors that may be indirectly related and exert different influences according to the analyzed environment .

Fundamental processes involved in the microbial degradation of coal and its derivatives have been well investigated and documented over the past two decades. However, limited progress in industrial application has been identified as bottleneck in further active development of the field. The sporadic and unanticipated growth of Cynodon dactylon (Bermuda grass) has been observed on the surface of some coal dumps in the Witbank coal mining area of South Africa. Preliminary investigations showed the formation of a humic soil-like material from the breakdown of hard coal in the root zone of these plants. The potential of this system to contribute to industrial scale bioprocessing of hard coal was investigated. This study involved an investigation of the C. dactylon/coal rhizosphere environment and demonstrated the presence of fungal species with known coal bioconversion capability. Amongst these Neosartorya fischeri was identified and its activity in coal bioconversion was described for the first time. Cynodon dactylon plant roots were also shown to be colonized by mycorrhizal fungi including Glomus, Paraglomus and Gigaspora species. The role of plant photosynthate translocation into the root zone, providing organic carbon supplementation of fungal coal bioconversion was investigated in deep liquid culture with the N. fischeri isolate used as the biocatalyst. Organic acids, sugars and complex organic carbon sources were investigated and it was shown that glutamate provided significant enhancement of bioconversion activity in this system. The performance of N. fischeri in coal bioconversion was compared with Phanaerochaete chrysosporium and Trametes versicolor, both previously described fungal species in the coal bioconversion application. Fourier transform infrared spectroscopy indicated more pronounced oxidation and introduction of nitro groups in the matrix of the humic acid product of coal bioconversion in N. fischeri and P. chrysosporium than for T. versicolor. Macro-elemental analysis of biomass-bound humic acid obtained from the N. fischeri catalyzed reaction showed an increase in the oxygen and nitrogen components and coupled with a reduction in carbon and hydrogen. Pyrolysis gas chromatography mass spectroscopy further supported the proposal that the mechanism of bioconversion involves oxygen and nitrogen insertion into the coal structure. The C. dactylon bituminous hard coal dump environment was simulated in a fixed-bed perfusion column bioreactor in which the contribution of organic supplement by the plant/mycorrhizal component of the system was investigated. The results enabled the proposal of a descriptive model accounting for the performance of the system in which the plant/mycorrhizal component introduces organic substances into the root zone. The non-mycorrhizal fungi utilize the organic carbon supplement in its attack on the coal substrate, breaking it down, and releasing plant nutrients and a soil-like substrate which in turn enables the growth of C. dactylon in this hostile environment. Based on these results, the Stacked Heap Coal Bioreactor concept was developed as a large-scale industrial bioprocess application based on heap-leach mineral processing technology. Field studies have confirmed that bituminous hard coal can be converted to a humic acid rich substrate in a stacked heap system inoculated with mycorrhizal and N. fischeri cultures and planted with C. dactylon.

The area around a plant’s roots hosts a complex and diverse microbial community. This environment can include a large number of bacteria that live on the surface of the root and benefit from the nutrients that the roots exude into the soil. These microbes can in turn be beneficial to the plant by protecting the roots from harmful fungi or stressful environmental conditions such as drought. In this thesis, several root-mimetic systems (RMSs) were developed for the study and growth of plant-beneficial bacteria in the laboratory environment. The RMS uses a porous hollow fiber used in hemodialysis as a surface for microbial growth. This fiber can either be draped into liquid nutrients or nutrients can be pumped through the hollow fiber with seepage through pores in the fiber to the outside. These systems are simple but well-controlled models of how a root would feed a bacterial community. The RMSs can be used to study how bacteria receiving nutrients through the RMS react to external factors, and if the bacterial response varies with nutrients received through the fiber. One such application is to study how plant colonizing microbes react to stressors like nanoparticle technology, a growing part of the fertilizer industry. Several different commercial hollow fiber membranes were explored as possible surfaces for microbe attachment. A synthetic polysulfone / polyvinylpyrrolidone hollow fiber membrane, treated with bleach to change the surface properties, was found to be a favorable surface for attachment of the beneficial root-colonizing microbe Pseudomonas chlororaphis O6 (PcO6). In addition to hollow fiber membrane chemistry, the nutrient composition delivered to the bacteria strongly influenced surface colonization and biofilm formation. Thus, using the hollow fiber root model, bacteria can be studied with respect to their responses to changes in nutrient composition as well as their response to stressors such as nanoparticles. Contrasted with studying bacteria on a living root, the model systems developed in this thesis allow microbes to be investigated without the added complexity of unknown variations in the nutrients that the roots pump into the soil.

Den presenterade studien hade som syfte att utveckla en extraktions-, provpreparerings- och analysmetod för jorden, i vilken gräset Cyperus rotundus växer, i ett försök att identifiera möjliga äggläggningsattraherande ämnen för myggan Anopheles gambiae. Högupplösande vätskekromatografi med hydrofob stationär fas (RP-HPLC, en.) med Masspektrometri med Elektrosprejjonisering (ESI-MS, en.) användes för separation och detektion av de extraherade proverna. Ett flertal extraktionssatser gjordes, där parametrar och tekniker ändrades under utvecklingen av arbetet. Ultraljudsassisterad extraktion (UAE) av jord i en 50:50 (v/v) blandning av metanol och vatten visades vara mest effektiv av de undersökta metoderna. Upprening av jordextraktioner med fastfasextraktion (SPE, en.) visades ha en positiv inverkan på signalintensiteten i kromatogrammen såväl som att reducera intensiteten av de systemtoppar som eluerar vid dödtiden. Detta indikerar att de poläraste ämnena har renats bort. En jämförelse gjordes mellan en extraktion av jord som legat i blöt i fem dagar och jord som extraherats utan att blötläggas. En skillnad kunde ses och visades genom att jämföra kromatogram och masspektra från de två proverna. Tandem-MS-experiment gjordes för ett flertal prekursorjoner med avsikt att identifiera ämnena genom jämförelse med databaserna Human Metabolome Database (HMDB), Metlin och Massbank, men inga överrensstämmande jämförelser kunde göras. Tandem-MS-resultaten användes även för att jämföra efter varandra följande kromatografiska toppar med liknande MS1-spektrum. En identifieringsmetod bör utvecklas innan metoden som presenterats i detta arbete valideras och vidareutvecklas. / The present study aimed to develop an extraction, sample preparation and analysis method for the rhizosphere soil of the grass Cyperus rotundus in an attempt to identify possible oviposition attractants of the Anopheles gambiae mosquito. Reversed Phase High Performance Liquid Chromatography (RP-HPLC) coupled online with Electrospray Ionization Mass spectrometry (ESI-MS) was used for the separation and detection of the extracted samples. Multiple extraction batches were done, altering parameters and techniques along the way. Ultrasound-Assisted Extraction (UAE) of the soil with a 50:50 (v/v) mixture of methanol and water was determined to be the most effective of the attempted methods. Purifying soil extracts with Solid Phase Extraction (SPE) showed to have an impact on the signal intensities in the chromatogram as well as reducing the intensity of system peaks eluting at the dead-time. This indicates that more polar compounds were removed during the SPE purification. A comparison was done between an extraction of soil soaked in water for five days and soil extracted without prior wetting. A difference could be seen and was shown by comparing chromatograms and mass spectra from the two samples. Tandem MS experiments were done for multiple precursor ions in order to identify the compounds by comparison in databases Human Metabolome Database (HMDB), Metlin and Massbank, but no matches in the databases were found. The tandem MS results were also used for comparison of consecutive chromatographic peaks with similar MS1-spectra. An identification method should be developed before the method presented in this work is validated and optimized further.

Résumé : Les biosystèmes d’oxydation passive du CH[indice inférieur 4] constituent une alternative techniquement et économiquement viable pour la réduction des émissions fugitives de CH[indice inférieur 4] dans l’atmosphère par les sites d’enfouissement. Directement intégrés au recouvrement final, ils sont constitués d’une succession de couche de matériaux au sein desquelles se développent les bactéries méthanotrophes capable d’oxyder le CH[indice inférieur 4] en CO[indice inférieur 2] de façon passive, en présence de l’oxygène moléculaire. La capacité des BOPMs à réduire les émissions de CH[indice inférieur 4] a été associée à plusieurs paramètres météorologiques et environnementaux, entre autres la végétation. L’objectif de ce projet est de déterminer l’effet de la végétation dans l’oxydation du CH[indice inférieur 4] par les biosystèmes. Pour atteindre cet objectif, des études de l’efficacité d’oxydation du CH[indice inférieur 4] dans des bacs pourvus de végétation, dans des conditions contrôlées de laboratoire et partiellement contrôlées de terrain, suivie d’une étude de la cinétique d’oxydation des sols de rhizosphère pré-conditionnés au CH[indice inférieur 4], ont été effectuées. Quatre bacs ont été testés, comprenant : le trèfle blanc (Trifolium repens L.), la fléole des prés (Phleum pratense L.), un mélange des deux espèces végétales (mélange) et le sol nu (dépourvu de végétation). Les résultats des bacs d’oxydation ont montré que, jusqu’à un débit de 100 g CH[indice inférieur 4]/m[indice supérieur 2]/jr, les espèces végétales n’avaient pas d’influence sur les résultats, et les efficacités d’oxydation étaient de l’ordre de ~100%. Au-delà de cette valeur, les efficacités étaient toujours élevées, et une différence statistiquement significative a été observée entre les espèces végétales. Le sol nu était le plus efficace, tandis que le mélange et le trèfle étaient les moins efficaces au laboratoire et sur le terrain respectivement. Néanmoins, les différences d’efficacités entre les bacs n’étaient pas très grandes et les taux d’oxydation dans les bacs n’ont pas cessé de croitre tout au long des essais, suggérant que la capacité d’oxydation maximale des bacs n’a pas été atteinte. L’étude de la cinétique d’oxydation a également montré que la végétation n’avait pas d’effet significatif sur les taux d’oxydation. Ces observations ne corroborent pas ce qui est rapporté dans la littérature concernant l’effet positif de la végétation. Néanmoins, les conclusions de cette étude ont été en adéquation par l’analyse des profils d’efficacité, de la biomasse racinaire et des caractéristiques physico-chimiques des sols du BOPM. Par ailleurs, un effet significatif de la végétation sur le degré de saturation en eau dans les BOPMs a également été observé. Cette dernière observation a été associée au mécanisme de régulation de la teneur en eau par les racines des plantes. Les principales limitations de cette étude concernaient la durée des essais et le nombre d’espèces végétales. En résumé, pour les espèces végétales testées, il a été démontré que la végétation ne constitue pas un facteur clé stimulant l’oxydation du CH[indice inférieur 4] dans les BOPMs. De plus, l’étude de la cinétique d’oxydation a montré que de meilleur taux d’oxydation étaient obtenus dans un sol de rhizosphère modérément pré-exposé au CH[indice inférieur 4] comparativement à un sol sans végétation, ou à une rhizosphère non pré-exposée ou très pré-exposée au CH[indice inférieur 4]. / Abstract : The passive CH[subscript 4] oxidation Biosystems are a cost-effective technology for the reduction of landfills fugitive CH[subscript 4] emissions in the atmosphere. As part of the final cover, they are made up of a sequence of soil layers capable to develop methanotrophic bacteria for passive CH[subscript 4] oxidation into CO[subscript 2], in the presence of molecular oxygen. The ability of biosystems to reduce CH[subscript 4] emissions was related to several meteorological and environmental parameters, including vegetation. The main objective of this project is to determine the effect of vegetation on CH[subscript 4] oxidation by biosystems. Studies of the CH[subscript 4] oxidation efficiencies of vegetated column under controlled conditions prevailing in the laboratory and under the partially controlled conditions in the field, followed by the study of the CH[subscript 4] oxidation kinetics of the preconditioned rhizospheric soil, were carried out. Four columns were tested, including: white clover (Trifolium repens L.), timothy grass (Phleum pratense L.), a mixture of both (mixture) and bare soil (control biosystem). The results of the column study showed that up to a loading of 100 g CH[subscript 4]/m[superscript 2]/d, plant species did not influence the results, and the CH[subscript 4] oxidation efficiencies were in the vicinity of ~ 100%. Beyond this value, the efficiencies were still high, and a statistically significant difference was observed between plant species. Bare soil was the most efficient while the mixture and white clover were the least in the laboratory and the field respectively. However, differences in efficiencies between the columns were not high and the oxidation rates continued to increase throughout the test, suggesting that the maximum oxidation capacity of the biosystems tested may have never been fully attained. The kinetics study also showed that vegetation did not have significant effect on CH[subscript 4] oxidation rate. These observations do not corroborate what is reported in technical literature on the positive effect of vegetation. Nevertheless, the findings of this study were adequacy with the analysis of the profiles of efficiencies, root biomass and physico-chemical characteristics of soils. Moreover, a significant effect of vegetation on the degree of water saturation in Biosystems was also observed. The latter was associated with the mechanism of water content regulation through plant roots. The main limitations of this study concerned the duration of the tests and the number of plant species. In summary, for the plant species studied herein, it was shown that the vegetation is not a key factor for enhancing CH[subscript 4] oxidation in biosystems. Moreover, the study of the kinetics of CH[subscript 4] oxidation showed that better oxidation rate were obtained in a moderately pre-exposed rhizospheric soil compared to bare soils, to never before pre-exposed or very pre-exposed rhizospheric soils to CH[subscript 4].

Commercial energy use in Arizona is different from the rest of the United States because of their high demand for air conditioning. Nearly half of the energy used in commercial buildings goes to heating, cooling, and ventilation. In an attempt to reduce overall every use in buildings, looking at these categories led to an examination of ventilation in buildings, which is the main cause for high heating and cooling costs. Ventilation of fresh air is required in order to provide a safe, healthy environment, with acceptable indoor air quality. Indoor air quality and pollution has continuously come to light as a major health concern for building occupants. Chemicals used in manufacturing allow consumers to buy and expose themselves to toxic substances such as volatile organic compounds on a daily basis. With minimal regulations on indoor air, it is important to find ways to better filter and clean it. The traditional solution is ventilation, but more fresh air ventilation means more heating and cooling. This paper explores the research that has been done on plants and phytoremediation and the applicability to indoor air quality. With the proof that certain combinations and amounts of plants can filter the air of volatile organic compounds, systems are explored for indoor air filtration instead of mechanical ventilation. This type of system can greatly reduce heating and cooling costs in buildings due to the reduction of outdoor air being brought in and requiring conditioning. A system of this type is a feasible solution to indoor air quality and can lead to a significant reduction in energy use. The proposed AIRMAPS is a system that in certain quantities can reduce the need for fresh air ventilation by 25%, which in turn has shown through the validation by eQUEST, that the energy used for heating, cooling, and ventilation fans can also be reduced by approximately the same amount. The plants used are spider plant, dumb cane, English ivy, and golden pothos. The average formaldehyde removal by each of these plants is a low approximation of 75% per cubic meter. This paper also considers the growing materials used for the plants; activated carbon, potting soil mix, and grow-stones, as well as their formaldehyde removal capabilities.

Controlled environment agriculture offers a solution to challenges including less available land, water deficits, and consumer demand for pesticide free produce. However, control of soil-borne diseases is a major limiting factor. The goal of this dissertation was to examine predictions of the hypothesis that border cells function to protect plant health by controlling microorganisms associated with plants grown in hydroponic culture. Border cells separate from root tips upon immersion in water, and appear to have important roles in the defense mechanisms of plant roots. The general objectives were (1) to study the delivery of border cells in hydroponics; (2) to evaluate interactions between border cells and microorganisms in hydroponics; and (3) to explore approaches to alter border cell production for improved root disease control. In this study it was confirmed that border cells can be released continuously into the solution of hydroponic culture suggesting that plants grown in this system may use extra energy in the production of new border cells. Free border cells interacted with microorganisms present in the hydroponic solution by secreting an extracellular capsule. Previous studies showed that proteins are a key component of this capsule, including lectins. The interaction of pea lectin and Nectria haematococca spores therefore was explored. Results demonstrated that pea lectin agglutinates fungal spores in a hapten-specific manner, and inhibits their germination. Lectin had no negative effect on root development suggesting that it could be used as a potential control for soil-borne diseases in hydroponics. To control the production of border cells, subsequent studies measured the impact of a transient exposure of root tips to different metabolites secreted by root caps and border cells. Exposure to specific metabolites altered the production of border cells without measurable effects on root growth and development. This is in contrast to results obtained with altered gene expression. For example, gene silencing of a border cell specific gene resulted in altered root growth.

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...

Arsenic (As) appears in the environment as various As species, which may vary in plant uptake and toxicity. Moreover, As exposure may vary between habitat due to availability and speciation, both of which are influenced by redox potential. To decrease As uptake, addition of silicate may be a tool. The aim of the study was to investigate how the external factors As availability, plant habitats, silicon and oxygen level, influenced the accumulation and speciation of As in plants for food and phytoremediation in a temperate region. The external factors were chosen due to their previously showed influence on As in plants. The risks with dietary As was investigated by plant As accumulation and speciation in carrot, lettuce and spinach grown in alum shale and glassworks soils, and by the influence of silicon on As accumulation in lettuce in hydroponics. Suitable plants for As phytoremediation was investigated by analysing plants from various habitats, and by the O2 influence on phytofiltration. The results showed that vegetables accumulated more As in soils with higher As extractability, and the As extractability in the rhizosphere was higher than in bulk soil. Also, the As concentration in lettuce was higher in hydroponics than in soil, but silicon reduced the accumulation of As in lettuce in hydroponics. Also, the more toxic inorganic As were the main As species detected in vegetables, compared with the less toxic organic As. For phytoremediation, the results showed a low As accumulation in emergent and terrestrial plants. Submerged plants had had a higher shoot As concentration. In general, the habitat had a major influence on the As accumulation in plants. The results also showed that the As accumulation properties in Elodea canadensis was reduced at higher O2. In conclusion, consumption of vegetables cultivated in As polluted soils can result in an elevated intake of inorganic As, and E. canadensis is a promising candidate for As phytofiltration in a temperate region. / <p>At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Manuscript; Paper 4: Manuscript; Paper 5: Manuscript.</p>