Berlin, Techn. Univ., Diss., 2004. / Computerdatei im Fernzugriff.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 378-394). Available also in a digital version from Dissertation Abstracts.

La nécessité de maîtriser les émissions de GES (CO2, NO), la raréfaction et la hausse du prix des carburants fossiles conduisent à envisager la substitution du C fossile par du C « renouvelable » c'est-à-dire issu de la biomasse végétale. Cette stratégie de substitution doit être durable. En particulier l’exportation massive de biomasse végétale privant le sol des restitutions de résidus végétaux (par exemple pour les pailles de céréales) ; et l’implantation de nouvelles cultures notamment des plantes pérennes (par exemple le miscanthus) interrogent sur les pratiques culturales, notamment les dates et les fréquences d’exportation, indispensables pour le maintien de la fertilité des sols et une bonne gestion des cycles biogéochimiques. Miscanthus×giganteus, plante pérenne à rhizome est une des plantes « candidate » pour la production des carburants de seconde génération, en raison de son fort potentiel de production de biomasse, y compris en conditions tempérées. Dans ce contexte l’objectif principal de ce travail de thèse était de quantifier et caractériser les litières végétales recyclées vers le sol sous culture de Miscanthus, plus précisément les feuilles sénescentes,les racines et rhizomes de Miscanthus et d’étudier la minéralisation du C et N au cours de leur décomposition. Ce travail s’est appuyé sur un essai au champ de Miscanthus×giganteus, âgé de 3 à 5ans, implanté depuis 2006 à Estrées-Mons (Nord de la France), et croisant 2 dates de récolte (une récolte précoce avant l’hiver et une récolte tardive après l’hiver en fin de cycle annuel) et 2 niveaux de fertilisation azotée (0 kg N ha-1 et 120 kg N ha-1). Tout d’abord sur les litières prélevées sur cet essai,nous avons quantifié, caractérisé biochimiquement et étudié la minéralisation en conditions contrôlées des feuilles sénescentes, rhizomes et racines. Ensuite la dynamique de chute des feuilles au cours de la sénescence, leur accumulation sous forme de mulch à la surface du sol et les cinétiques de décomposition ont été étudiées au champ pendant deux années. Enfin nous avons étudié les effets de la disponibilité de l’azote sur la dynamique du C et N, la dynamique microbienne et des fonctions enzymatiques au cours de la décomposition de ces feuilles, en conditions contrôlées. La disponibilité en N a été modulée soit en apportant de l’azote minéral, soit en apportant des quantités croissantes de feuilles pour une quantité d’azote donnée. Nous montrons que le C stocké dans les trois " compartiments " recyclés potentiellement au sol est considérable : feuilles sénescentes (1à 3 t C ha-1 par an), racines (1 à 2 t C ha-1) et rhizomes (7 à 10 t Cha-1). Les rhizomes, ont une teneur en soluble-NDS de 25 à 35% et une teneur en lignine de 11 à 15% selon les prélèvements précoces ou tardifs, et une teneur en N élevée (0.7-1.5%). On observe en 263jours à 15 °C, une minéralisation des rhizomes représentant 61±8% du C apporté, supérieure à celle observée pour les racines (36±8%) et les feuilles sénescentes (53±4%). Nous montrons l’importance des feuilles sénescentes de Miscanthus dans le recyclage de matière organique vers le sol : le scénario de récolte précoce prive le sol d’un recyclage annuel de 1-3 t C ha-1 ; d’autre part qualitativement, la faible dégradabilité observée au laboratoire pour les feuilles est confirmée au champ, ce qui conduit à la formation d’un mulch important en épaisseur (2 à 4cm) et en quantité (équivalent à 6 à 7 t C ha-1).Enfin, une forte disponibilité en N accélère la vitesse de minéralisation du C à court terme. Ceci se traduit aussi par une augmentation du C microbien et de l’ergostérol, marqueur fongique, ainsi que des activités enzymatiques liées à la dégradation du C et N (xylanase, leucine aminopeptidase). En revanche, cette disponibilité forte en N réprime l’activité laccase. Nous montrons aussi que diminuer la disponibilité relative en N pour les décomposeurs, par ajout de quantités croissantes de feuilles dans le sol conduit à ralentir la croissance microbienne et fongique. Cette situation favorise très tôt l’installation de la biomasse fongique (augmentation du rapport ergostérol/C microbien) et son activité(laccase).Ce travail montre que la culture de Miscanthus permet potentiellement une forte accumulation de C organique, ce qui est favorable au maintien de la fertilité des sols à long terme. Il est maintenant essentiel de pouvoir prédire le devenir du C des parties souterraines de Miscanthus, dans la perspective de changement dans l’utilisation des terres. / To control emissions of greenhouse gases (CO2, NO), fossil fuels scarcity and their rising prices lead to consider the substitution of fossil C by the "renewable" C from plant biomass. This alternative strategy must be sustainable. In particular the massive export of plant biomass depriving soil of plant residues (eg cereal straws), and the growing of new crops specially perennial crops (eg miscanthus)questioned the cultural practices (dates and frequency of biomass export) essential for maintaining soil fertility and good management of biogeochemical cycles. Miscanthus × giganteus, a rhizomatous perennial grass is dedicated to second-generation fuels production, because of its high potential biomass production.In this context the main objective of this work was to quantify and characterize Miscanthus plant litter recycled to soil, more precisely senescent leaves, roots and rhizomes of Miscanthus, and to study the C and N mineralization during decomposition of these litters. This work was performed on 3 to 5 years old Miscanthus stands established since 2006 in Northern France (Estrées Mons), either fertilized with120 kg N ha−1 year−1 or unfertilized. The sampling of litters was performed in autumn (maximal biomass production) and winter (maturity). Firstly we quantified and biochemically characterized Miscanthus senescent leaves, rhizomes and roots. Then we studied their decomposition in soil under controlled conditions (15°C, -80 kPa) during 263 days. We also investigated in the field for two years the dynamics of leaf fall during senescence, their accumulation in the form of mulch on soil surface and the kinetics of decomposition. Finally we investigated under controlled conditions the effects of nitrogen availability on C and N dynamics, microbial dynamics and enzymatic functions during the decomposition of these leaves. N availability was modulated either by adding inorganic nitrogen, or by adding increasing amounts of leaves for a given amount of nitrogen in soil.Our results showed that the C stored in the three "compartments" recycled to soil is potentially considerable: senescent leaves (1 to 3 t C ha-1 year), roots (1 to 2 t C ha-1) and rhizomes (7 to 10 t C ha-1). The rhizomes had a high NDS soluble content (25 to 35%), a high N content (0.7 to 1.5%) and low lignin content (11 to 15%) depending on early or late harvest dates. we observed after 263 days of decomposition at 15°C a higher carbon mineralization from rhizomes 61 ± 8%, than that observed for roots (36 ± 8%) and senescent leaves (53 ± 4%). We also showed the importance of senescent leavesin the recycling of organic matter in the soil: the early harvest scenario deprives the soil of an annual leaves of 1-3 t C ha-1. Qualitatively, the low degradability observed in the laboratory experiment for the leaves was confirmed in the field. This leads to the formation of an important thick layer of mulch(2 to 4cm) and quantitatively (6-7 t C ha-1). Finally, a high N availability increases the C mineralization rate in the short term which was reflected by an increase in microbial C, fungal ergosterol, and enzymatic activities related to C and N degradation of (xylanase, leucine aminopeptidase). However, this high N availability suppresses laccase activity. We also showed that decreasing N availability for decomposers by adding increasing amounts of leaves in the soil leads toslow microbial and fungal growth. However, this situation favors an early installation of fungal biomass (increased ergosterol / microbial C ratio) and their activity (laccase).This work showed that the cultivation of Miscanthus potentially allows a large accumulation of organic C which is favorable to the maintenance of soil fertility in the long term. It is now essential to predict the fate of underground C parts of Miscanthus, in the perspective of change in land use, i.e.when the Miscanthus stands is to be replaced in field by another crop.

Student Number : 0316126G - MSc dissertation - School of Animal, Plant and Environmental Sciences - Faculty of Science / I investigated whether inorganic contaminants associated with gold mining waste discharges in the Free State Province, South Africa, were accumulated by a threatened species of lizard, Cordylus giganteus; if the route of exposure could be dietary, and whether accumulation of contaminants could be associated with potential physiological costs. I compared elemental concentrations in tissue and blood samples between populations of this species, from four sites around the province. Inorganic contaminants were known to be elevated in soils, water, sediments and vegetation of the first mining site, and to a lesser extent at the second mining site. The third site was not known to be contaminated by mining discharges, but was selected because of its potential to be contaminated by wind-blown contaminants. This site was also heavily overgrazed. The fourth site was both uncontaminated by mining and relatively undisturbed. Lizards from the most contaminated site had significantly higher blood concentrations of Li, Na, Al, S, Ca, P, Si, Cr, Mn, Fe, Ni, W and Bi when compared with all the other sites investigated. Based upon a comparison of elemental concentrations in selected lizard prey items found at these sites (Coleoptera, Tenebrionidae) I did not find conclusive evidence for a dietary route of exposure to contaminants. I tested for significant differences in body condition among populations. Lizards from the heavily grazed site were in similar condition to lizards from the most contaminated site, and all these lizards were in significantly poorer condition than lizards from the undisturbed site. The adult sex ratio of the population inhabiting the most contaminated site also deviated significantly from an expected 1:1 ratio in favour of females. The reason for this deviation is not understood, but may be a consequence of sexes being differentially affected by inorganic contaminants. My research demonstrates that the disposal of gold and uranium mine waste has resulted in the accumulation of contaminants by a representative resident vertebrate, and that this accumulation is potentially associated with poorer body condition which might affect fitness. It highlights the potential threat of mining-waste discharges to lizards, shows the need for site remediation measures, and also highlights the need for further investigation into the potential effects of environmental contaminants from gold and uranium mine waste on exposed vertebrates in South Africa.

Thesis (Ph. D.)--University of Washington. / Bibliography: l. [144]-150.

Techn. Universiẗat, Diss., 2004--Berlin.

Submitted by dayse paz (daysepaz@hotmail.com) on 2016-04-06T14:31:14Z No. of bitstreams: 1 Disserta_o_Daiane_KAFER.pdf: 1161357 bytes, checksum: 583dfb9dd82e3830703145f214aa3bf1 (MD5) / Approved for entry into archive by cleuza maria medina dos santos (cleuzamai@yahoo.com.br) on 2016-05-10T19:58:37Z (GMT) No. of bitstreams: 1 Disserta_o_Daiane_KAFER.pdf: 1161357 bytes, checksum: 583dfb9dd82e3830703145f214aa3bf1 (MD5) / Made available in DSpace on 2016-05-10T19:58:37Z (GMT). No. of bitstreams: 1 Disserta_o_Daiane_KAFER.pdf: 1161357 bytes, checksum: 583dfb9dd82e3830703145f214aa3bf1 (MD5) Previous issue date: 2013 / Neste estudo, investigamos a composição e distribuição das macrófitas aquáticas de uma área úmida no sul do Brasil conhecida como Banhado 25 e sua relação com algumas variáveis abióticas. Para tanto foram alocadas 30 unidades amostrais permanentes de 1m2 distribuídas em duas áreas: uma com domínio de Scirpus giganteus Kunth (Área A) e outra com domínio de Cladium jamaicense Crantz (Área B) onde realizamos a identificação e estimativa da cobertura das macrófitas durante dois períodos, inverno e verão. Simultaneamente foram avaliadas características químicas do sedimento, a profundidade da água e a radiação fotossinteticamente ativa (PAR) em cada unidade amostral. Foram identificadas 66 espécies distribuídas em 27 famílias nas duas áreas estudadas durante os dois períodos amostrados. Os valores de riqueza de espécies (S), diversidade de Shannon (H’) e o equabilidade de Pielou (J’) diferiram entre as áreas amostradas, assim como a composição de espécies, apresentando maiores valores na área B. A área A apresentou uma maior dispersão multivariada quando comparada com a área B, ocorrendo uma maior variabilidade de espécies nas unidades amostrais. A ordenação das unidades amostrais da análise de correspondência canônica (CCA) evidenciou a diferença entre as duas áreas, onde a área A esteve associada a profundidade da coluna d’ água, PAR e ao teor de alumínio no sedimento enquanto que a área B esteve associada ao pH, Mg e Ca. O coeficiente de Spearman indicou correlação negativa entre a cobertura das espécies dominantes e a riqueza de espécies, assim como com a taxa de radiação fotossintéticamente ativa que chega ao substrato. Concluímos que a variação na composição e distribuição das macrófitas refletiu a heterogeneidade espacial e temporal do Banhado 25. / In this study, we have investigated the composition and distribution of macrophytes in two locations of a wetland in southern of Brazil and its relation to abiotic variables. For this purpose were allocated 30 permanent samples units of 1m² divided into two areas: one area of Scirpus giganteus Kunth (Area A) and another domain of Cladium jamaisence Crantz (Area B) where we performed the identification and estimation of coverage of macrophytes during two periods, winter and summer. Simultaneously were evaluated chemical characteristics of the sediment, water depth and photosynthetic active radiation (PAR) in each sample unit. We identified 66 species distributed in 27 families in the two areas studied during the two periods. Species richness (S) values, Shannon index (H’) and Pielou equability (J’) showing difference between the sampling sites, as well as species composition, with higher values in the area B. The area A showed a greater dispersion multivariate compared to the area B, occurring a greater variability of species in the sample units. The ordination of sample units of canonical correspondence analysis (CCA) showed the difference between the two areas, where the area A was associated to the depth of the water column, PAR and the aluminum content in the sediment while area B was associated to the other chemical sediment variables. The Spearman correlation coefficient indicated a negative correlation between the cover of the dominant species and species richness, as well as the rate of photosynthetic active radiation that reaches to the substrate. We have concluded that variation in the composition and distribution of macrophytes reflected the spatial and temporal heterogeneity of Banhado 25.

L’objectif de cette thèse a été d’évaluer les possibilités de réhabilitation de sols dégradés, contaminés par des HAP ou à faible qualité agronomique (parc à cendres volantes), en couplant la bioremédiation de ces sols à la culture de Miscanthus x giganteus (MxG). Dans un premier temps, la mise au point d’une série de bioessais in vitro au format microplaque a permis de témoigner de la contribution spécifique des exsudats racinaires de MxG et plus particulièrement de la quercétine (identifié parmi les métabolites secondaires racinaires) dans la biostimulation de bactéries HAP-dégradantes. Afin d’appréhender l’effet rhizosphérique de MxG sur la qualité des sols, des cultures en microcosmes de sols reconstitués puis de sols de friches ont été menées en laboratoire. D’une part, la dissipation significative des HAP à 4 cycles a pu être mesurée dans le compartiment racinaire des sols contaminés. D’autre part, l’augmentation des teneurs en carbone organique observée dans les cendres volantes, associée à une dynamisation du cycle de l’azote suggèrent une accélération des processus pédogénétiques liés au « vieillissement » du substrat. En outre, le développement d’un protocole d’extraction et de purification d’acides nucléiques a permis de suivre l’évolution de la diversité des communautés bactériennes des sols par méthode PCR-TTGE des ADNr 16S microbiens. La sélection de phylotypes bactériens a été mise en évidence au niveau rhizosphérique, en particulier à l’interface sol-racine (rhizoplan), soulignant l’influence de processus racinaires sur la structuration des communautés bactériennes in vivo. Enfin, un dernier volet, rendant compte d’expériences exploratoires sur deux saisons de croissance en champs (sols pollués et parc à cendres), a permis de confirmer l’adaptation de MxG à la variété de substrats étudiés, suggérant que sa culture pourrait constituer une alternative d’agriculture durable sur sites contaminés / The aim of this work was to investigate the potential of Miscanthus x giganteus (MxG) for PAH polluted soils remediation and fly ash revegetation. In vitro studies through microplate assays demonstrated the contribution of MxG root exudates and particularly of quercetin (following the identification of root secondary metabolites) to the selective biostimulation of PAH-degrading bacteria. To get insights into bioremediation processes and rhizosphere effects on soil quality, microcosm experiments were conducted at a laboratory scale, using artificially reconstituted soils and collected industrial soils. On the one hand, significant dissipations of four-ring PAH were noticed in the rhizosphere of contaminated soils. On the other hand, significant organic carbon and nitrite inputs could be measured in fly ash, indicating a “restart” of nitrogen cycle and suggesting an enhancement of fly ash weathering processes in the long term. Besides, the development of a soil nucleic acid extraction and purification method permitted to study the evolution of bacterial community diversity in all types of soils, based on PCR-TTGE of eubacterial 16S rDNA. Specific enrichments of bacterial phylotypes could be reported in rhizoplanes, confirming root-associated processes on the selection of soil bacterial communities. Finally, plant adaptation to the broad range of studied substrates in situ lead us to suggest that MxG cultivation could be an effective strategy for a new system of sustainable agricultural activities in wasteland soils

Inulase had received little attention and there were conflicting statements about its availability in animals.Adapted anthrone-sulfuric acid and Nelson-Somogyi reagents were used for identifying fructose concentration in inulin hydrolyzed by insect and aerobic bacteria extracts as a measure of inulase activity.Bacteria isolated from the insect’s gut were grown in nutrient agar and their extracts were used in hydrolyzing inulin. Aerobic bacteria-free insect extracts were obtained by injecting aureomycin into the gut of the cockroaches.There was no significant aureomycin effect on inulase production by the insects. The greatest inulase activity was around the gastric ceaca region. The major inulase requirement of the insects was met by gastric ceaca region production and not by the bacteria. The assertion that inulase may not be found in animal workd (Bernfeld 1962, Doby 1965, Hoar 1966) is unsupported. Periplaneta americana (Linnaeus) and Blaberus giganteus (Linnaeus) have inulase in their gastric caeca regions.Studies of inulase could lead to better understanding of cockroach physiology and their symbionts. If inulase is eventually synthesized in the laboratory a significant amount of inulin energy would become available to man through the use of synthetic inulase.Honors CollegeBall State UniversityMuncie, IN 47306

[pt] O bambu é um material compósito lignocelulósico natural, local, renovável e abundante, importante para o sequestro de carbono da atmosfera, caracterizado pela classificação funcional multidimensional e pela matriz consideravelmente porosa reforçada por fibras longas. Tais configurações proporcionam baixa densidade aliada a propriedades mecânicas adequadas à construção civil. Este trabalho propõe combinar aproveitamento adequado e alto desempenho, aplicando configurações diferenciadas a compósitos laminados, utilizando material proveniente de diferentes trechos da parede do colmo, de acordo com os requerimentos estruturais, de uma maneira viável para o desenvolvimento de formas complexas. Foram sistematizadas e propostas novas configurações para normas de ensaios de controle bem como procedimentos e ensaios específicos para a caracterização mecânica de lâminas, e para compósitos laminados de bambu. No intuito de quantificar e caracterizar a organização morfológica do bambu, principalmente relacionada à sua alta porosidade, foram conduzidas análises microestruturais diversas. Os dados foram correlacionados com as propriedades mecânicas obtidas experimentalmente de regiões similares. Desenvolveu-se ainda um método simplificado para estimar o teor total de vazios em lâminas baseado em ensaios de variação de umidade. Observou-se que a fração de vazios varia de acordo com uma classificação funcional e influencia, não somente na densidade do material, mas também em suas propriedades mecânicas. Os empacotamentos propostos para os laminados foram analisados em programa comercial de Elementos Finitos. / [en] Bamboo is a natural, local, renewable and abundant lignocellulosic material, important to mitigate greenhouse gases emissions. It is characterized by the multidimensional functionally graded structure and for its long fiber reinforced porous matrix. Such configurations provide the combination of low density and high mechanical properties, which are compatible with the ones of usual construction materials. Laminated bamboo composites are currently produced aiming either high productivity and complex geometry with low performance, or simple geometry for structural purposes with a very low productivity. This work proposes a protocol to combine productivity, possibility of complex geometry and high performance, by applying laminae obtained from different parts of the culm wall, regarding to the radial axis, according to the structural requirements. New configurations for standard mechanical test methods were proposed for material s compliance checking and both for laminae and laminates characterization. In parallel, aiming to quantify and morphologically characterize, mainly the bamboo porosity variation, several microstructural analyzes have been used. The results were compared with the ones obtained on the experimental mechanical characterization protocol. A simplified method to quantify bamboo porosity based on humidity variation tests has been developed and validated by the comparison with digital image processing. It has been observed that bamboo s porous volume fraction is functionally graded and has influence on the material s density as long as on its mechanical properties. The proposed laminate configuratons were analyzed on a commercial Finite Element Method software.