Le pois chiche (Cicer arietinum L.) a l’avantage de pouvoir assimiler l'azote atmosphérique grâce à son association symbiotique avec des bactéries du genre Mesorhizobium. Malgré cet effet bénéfique sur les systèmes culturaux, le pois chiche réduit parfois la productivité du blé qui la suit. Cet effet négatif du pois chiche pourrait provenir d’une réaction allélopathique à ses exsudats racinaires ou résidus, ou de changements inopportuns dans la communauté microbienne du sol induits par la plante. L'amélioration des interactions symbiotiques du pois chiche pourrait améliorer la performance économique et environnementale des systèmes culturaux basés sur le blé. L’objectif à long terme de ce travail est d'améliorer l’influence du pois chiches sur son environnement biologique et sur la productivité du système cultural. À court terme, nous voulons 1) vérifier l'effet des champignons endophytes sur la performance de cultivars de pois chiche de type desi et kabuli, particulièrement en conditions de stress hydrique, ainsi que sur celle d’une culture subséquente de blé dur, 2) identifier des cultivars de pois chiche capables d’améliorer la qualité biologique de sols cultivés, 3) vérifier que des composés biologiquement actifs sont présents dans les racines des différents cultivars de pois chiches et 4) définir la nature de l’activité (stimulation ou inhibition) des ces composés sur les champignons endomycorhiziens à arbuscules (CMA), qui sont des microorganismes bénéfiques du sol reconnus. L’inoculation du pois chiche avec des champignons endophytes indigènes en serre a augmenté la tolérance à la sécheresse du cultivar de type kabuli à feuille simple CDC Xena et amélioré la nutrition azotée et phosphatée d’un cultivar de type desi, cv. CDC Nika, cultivé en conditions de stress hydrique. La germination des graines de blé dur fut meilleure lorsque celles-ci étaient semées dans les débris de pois chiche inoculé de type kabuli. Le sol dans lequel le génotype de pois chiche à feuille simple CDC Xena fut cultivé mais duquel tout le matériel végétal de pois chiche fut retiré a fortement inhibé la germination des semences de blé dur, ce qui suggère un effet des exsudats racinaires sur la communauté microbienne du sol associée à cette variété de pois chiche. En champ, les cultivars de pois chiche ont influencé différemment la composition des communautés de champignons de la rhizosphère. Les espèces de champignons pathogènes étaient infréquentes et les espèces saprotrophiques et de CMA étaient fréquentes dans la zone des racines du cultivar de type desi CDC Anna. L’effet des composés contenus dans les fractions séparées par HPLC et solubles en solution de méthanol à 25% et 50% de l’extrait racinaire de ce cultivar sur la germination de spores de CMA a été testé in vitro. Les deux espèces de CMA utilisées ont répondu différemment à l’exposition aux composés testés, révélant un mécanisme impliqué dans l’association préférentielle entre les plantes hôtes et les CMA qui leurs sont associés. Nous concluons que le génotype de pois chiche influence la composition de la communauté microbienne qui lui est associée et que cette influence est reliée au moins en partie aux molécules bioactives produites par les racines de la plante. D’autre part, la productivité du pois chiche et de la culture subséquente pourrait être favorisée par la manipulation de leurs champignons endophytes par inoculation. / Chickpea (Cicer arietinum L.) has the ability to bring free N into cropping systems, but is only a fair rotation crop, leading to lower yield in following wheat crops, as compared to medic, vetch or lentil. The negative effects of a chickpea plant on the following wheat crops could come from chickpea root exudates, their residues or their influence on the soil microbial community. The identification of chickpea cultivars best able to promote soil biological quality and the growth of a subsequent crop in rotation will help farmers in selecting better crop rotations and, thus, will improve crop management in soil zone growing chickpea. The global objective of this research is to improve the fitness of chickpea crops to their biological environment and to improve the ability of the plant to enhance soil biological quality. The specific objectives were (1) to verify that the productivity of chickpea and subsequent crops could be promoted through the inoculation by some indigenous endophytic fungi particularly under drought stress conditions (2) to verify the existence of variation in the rhizospheric associations of field-grown chickpea, as it is a necessary condition for the selection of genotypes with improved compatibility with beneficial microorganisms. (3) to identify the biologically active compounds present in the root extracts of chickpea cultivars with contrasting phenotypes, and assess their effect on beneficial and pathogenic soil microorganisms. The greenhouse experiments show that inoculation with indigenous endophytes increased drought tolerance of the unifoliate Kabuli chickpea CDC Xena and the N and P nutrition of the drought stressed Desi chickpea CDC Nika. Inoculation of both Kabuli chickpea varieties with indigenous endophytes improved wheat seeds germination in tissues amended soil. Residue-free soil previously growing the unifoliate Kabuli chickpea CDC Xena strongly inhibited durum seed germination suggesting an effect of root exudates on the soil microbial community, with this Kabuli chickpea variety. In a field experiment, the fungal diversity in cultivated Prairie dryland appeared to host a large array of fungal groups known to reduced plant nutrient, water and biotic stresses, and chickpea genotypes influenced differently the composition and biomass of the soil microbial community. The Desi chickpea CDC Anna was associated with high diversity of arbuscular mycorrhizal fungi (AMF) and culturable fungi, favored the proliferation of soil bacteria and fungal genus hosting biocontrol agents, and developed high AM root colonization level, as compared to the three Kabuli genotypes examined. The HPLC fractions of the roots of chickpea cultivar CDC Anna were recovered and the effects of these fractions on AM fungal spore germination were assayed in multi-well plates. Root extract fractions affect in a different ways the percentage of spores’ germination of Glomus etunicatum and Gigaspora Rosea. We concluded that the genotype of chickpea plants influences the composition of the associated microbial community, and this influence may be related to molecular signals produced by the plants. Furthermore, the productivity of chickpea and subsequent crops could be promoted through the inoculation with indigenous endophytic fungi. / réalisé en cotutelle avec la Faculté des Sciences de Tunis, Université Tunis El Manar.

Dans le contexte actuel, les communautés scientifiques et politiques sont centrées sur les différentes manières de mieux préserver et utiliser les ressources naturelles de notre planète. Dans le but de réduire la consommation des matières issues du pétrole, et de développer de nouveaux produits et procédés industriels plus propres, l’industrie des fragrances et des arômes cherche aujourd’hui à développer de nouveaux matériaux bio-sourcés pour protéger leurs molécules volatiles odorantes. Dans ce travail de thèse, les maltodextrines ont été choisies comme composé majoritaire, les protéines de pois et un amidon modifié ont été sélectionnés comme additifs compatibilisants pour la composition des matrices d’agromatériaux. L’incorporation des molécules volatiles odorantes, ainsi que l’élaboration des matrices encapsulantes ont été réalisées en une seule étape, grâce à la technologie d’extrusion bi-vis à basse température. Les caractéristiques physicochimiques, thermiques et morphologiques de ces nouvelles matrices enrobantes ont été analysées, de même que la détermination de leur efficacité d’encapsulation et du profil de libération du principe actif. Les différentes investigations menées ont permis de mieux comprendre l’impact des formulations et de l’incorporation des molécules volatiles odorantes sur les paramètres opératoires. Les interactions entre la matrice enrobante et le principe actif ont également été étudiées. Les conditions d’extrusion établies, ainsi que les caractéristiques de ces nouvelles matrices encapsulantes, s’avèrent être pertinentes pour le domaine de la parfumerie. / Nowadays, scientific and political communities are focused on ways to better preserve and manage the natural resources of our planet. In order to reduce consumption of fossil resources, and to develop more environmentally friendly industrial processes, the industry of flavors and fragrances became interested in developing new bio-based encapsulating materials. In the present work, maltodextrins have been chosen as main component of the matrix, and pea protein isolate and a modified starch were selected as compatibilizing additives. The incorporation of volatile odorant compounds and the elaboration of the new bio-based delivery systems were performed, all in one single step, by low temperature twin-screw extrusion. The physicochemical, thermal and morphological properties of these matrices were studied, as well as the encapsulation efficiency and the release profile of the active compounds. These investigations have led to a better understanding of the impact of the formulations and of the incorporation of the active compound on the process parameters. The interactions between the wall and the encapsulated materials were also analyzed. The characteristics of the new bio-based delivery systems and the established extrusion process conditions were found to be very promising to be employed in the field of perfumery.

Chez les plantes, le RET (Root Extracellular Trap) est une structure cellulo-moléculaire jouant un rôle central dans la défense racinaire face aux stress abiotiques et biotiques. De nombreuses similitudes de composition ont été observées entre le RET et le NET (Neutrophil Extracellular Trap) du système immunitaire des mammifères, connu pour capturer et tuer certains microorganismes bactériens et fongiques. Le RET est composé de cellules frontières et de leurs sécrétions (composés de haut et de bas poids moléculaire) comprenant des polysaccharides de la paroi cellulaire, des protéoglycannes et des métabolites secondaires. Il contient également des protéines antimicrobiennes et de l'ADN extracellulaire, tout comme le NET. Dans le cadre de mon projet de thèse, nous avons caractérisé la composition moléculaire et la structuration de cette entité de défense chez deux légumineuses, le soja (Glycine max (Merr) L.) et le pois (Pisum sativum L.), par des approches d’imagerie cellulaire photonique et électronique. Nous avons également étudié l’impact du RET du soja sur des pathogènes telluriques, à savoir Phytophthora parasitica et Aphanomyces euteiches. Nous avons ainsi pu mettre en évidence la présence de différents morphotypes de cellules frontières et de mucilage au sein du RET de soja et de pois. Pour la première fois, nous avons montré la présence d’hétéromannanes, de xyloglucane et de cellulose dans le RET, formant une ossature stabilisant le mucilage et reliant les cellules frontières entre elles. Ces polysaccharides structuraux semblent être essentiels à l’intégrité structurale et fonctionnelle du RET. Enfin, nos résultats ont montré que le RET de soja était impliqué dans la défense précoce de la racine contre P. parasitica. Cette étude apporte de nouvelles connaissances relatives à la composition moléculaire et la structure du RET, nous amenant ainsi à comparer le RET à d’autres modèles que le NET des mammifères, tels que les biofilms bactériens et les mucilages de graines. En effet, de nombreuses similitudes existent entre ces différents complexes en termes de composition et de fonctionnement, qui méritent d’être explorer plus en détail dans l’avenir. / In higher plants, the RET (Root Extracellular Trap) is a complex made up of border cells and secretions, released by root tips and believed to play a central role in biotic and abiotic stress tolerance. This structure is quite similar to the Neutrophil Extracellular Trap (NET) known as one of the first lines of defense in mammals, able to trap and kill microbial pathogens. RET secretions consist of high and low-molecular weight compounds including cell wall polysaccharides, proteoglycans and secondary metabolites. They also contain a variety of anti-microbial proteins and extracellular DNA much like the NET. During my thesis work, we investigated the release and morphology of root border cells in soybean (Glycine max (Merr) L.) using light and scanning electron microscopy. The molecular composition of the mucilage was also investigated using immunocytochemistry, anti-cell wall glycan antibodies and confocal microscopy. Immunocytochemistry was also applied to pea (Pisum sativum L.) border cells and secretions to examine the occurrence of specific polysaccharides. We also studied the impact of soybean RET on the soilborne pathogens, Phytophthora parasitica and Aphanomyces euteiches. Our findings showed that root tips of soybean released three border cell morphotypes all of which secreted substantial amounts of mucilage. Immunocytochemical data showed that mucilage was enriched in pectin and the two hemicellulosic polysaccharides xyloglucan and heteromannan. Mucilage also contained cellulose, histone and extracellular DNA. Interestingly, the structural polysaccharides formed a fibrous network surrounding the cells and holding them together, supporting their role in maintaining mucilage architecture and integrity. In addition, we found that xyloglucan and cellulose were also secreted into the mucilage of pea, connecting border cells together. Finally, our findings revealed that RET prevented P. parasitica zoospores from colonizing soybean root tip, by stopping their penetration and inducing their death. Overall the study revealed novel insights into the composition, structure and function of plant RETs. Currently, the RET is much less studied than its mammal counterpart, the NET, but structural and functional similarities exist between these two traps. Interestingly, similarities do also exist between the RET and other important biological complexes, including bacterial biofilms and seed mucilage, that deserve to be further investigated and compared in the context of immunity.

RAMOS, Jeannette Filomeno Pouchain. Projeto educativo e político-pedagógico da escola De ensino médio: tradições e contradições na gestão e na formação para o trabalho. 2009. 245f. Tese (Doutorado em Educação) – Universidade Federal do Ceará, Faculdade de Educação, Programa de Pós-Graduação em Educação Brasileira, Fortaleza-CE, 2009. / Submitted by Maria Josineide Góis (josineide@ufc.br) on 2012-07-09T11:46:49Z No. of bitstreams: 1 2009_Tese_JFPRamos.pdf: 2192405 bytes, checksum: 71c4d8335d8c1d60c3331ea87534ab26 (MD5) / Approved for entry into archive by Maria Josineide Góis(josineide@ufc.br) on 2012-07-13T11:18:44Z (GMT) No. of bitstreams: 1 2009_Tese_JFPRamos.pdf: 2192405 bytes, checksum: 71c4d8335d8c1d60c3331ea87534ab26 (MD5) / Made available in DSpace on 2012-07-13T11:18:44Z (GMT). No. of bitstreams: 1 2009_Tese_JFPRamos.pdf: 2192405 bytes, checksum: 71c4d8335d8c1d60c3331ea87534ab26 (MD5) Previous issue date: 2009 / The Brazilian education, founded by the logic submission of the educational project from the Jesuits, and the influences from the French, English and Americans, passed on to be considered a national problem with the proclamation of the republic in 1980. The attempt to regulate and to consolidate the social function propaedeutics, which denies the work, the industrialization who demanded the instrumental education for work and the reestablishment of the democracy in the state which reorganized the flexible production and impose the formation of a new type of worker (KUENZER, 1998) presents contradictories movements. In agreement with transformation the scientific technical conception of organization adopted participative democratic mechanism. Recognizing the contradiction in keeping distinct types of logic and the tendency of the liberal logic over the social logic, the challenger of the work management is to reverse this premise. As an alternative to the educational middle class project, the polytechnic education proposes to overcome the dual structure and history by omni lateral formation (SAVIANI, 2003). The elementary and middle school should be guided by the work as an excellent base for education (PISTRAK, 2005). The school, known as the work product of man, should be linked to school life as a social transformation combined with school education with material production and to promote self and social emancipation. In context, the general objective is to analyze the experience of reorganizing the educational work in creation of the politic pedagogic project of middle school, identifying perspectives, limits, possibilities, and resistances. The specifics objectives are to examine the evolution of the educational project in the social politic and economic history of Brazil, highlighting the management of school work and the formation of the young for work; analyze fundamentals, intentions and practices which guide the politic pedagogic project and identify and analyze the limits, possibilities and ways of group resistances in the management project. We choose as a theoretical methodological referential the Critic Theory and the method with materialistic history base. As instruments of qualitative and quantitative data collection we applied questionnaires, semi-structures interviews and focal groups. Among hypothesis should public school follow the educational project of middle class or should it follow the lines of vocational extent, instrumental; to attend to middle class project of the popular sector? The hard format of school has accomplished changes in the lines of directions? The politic pedagogic project working at Liceu do Maracanaú establish four pillars which reorganize the work in the school bearing in mind the full formation of the young. This school thinks, conceives and evaluates opposition to the others schools; it breaks with the traditional format of the work organization. The multiples intelligences are understood as principles, the project of work is the means to transformation of popular knowledge to the scientific knowledge with practice and social application of ideas in development of competencies and abilities, as means an half-yearly organizational and the evaluation as the learning observation. Scientific initiation in middle level education attends the interests of the school, highlighting the talents, improving the indicators and presenting results. This project is contradictory because the fundamentals and practice pedagogic reassures the principles of the traditional format and the process of schooling. This way the study confirms that is possible reorganize the work and this is done by the politic pedagogic project (PPP). Faced with the new demands the schools find themselves in a cross road and their functionality is placed at doubt. As a result of this, we point out the crises of education, formation of young and the society. It is necessary to invest in the contradictions of the system and take possession of them to construct another, the opposite and reverse. It is up to the intellectuals and educators to do their job. / A educação brasileira, permeada pela lógica da submissão do projeto educativo dos jesuítas, das influências francesas, inglesas e dos Estados Unidos da América, passa a ser considerada como problema nacional com a Proclamação da República em 1890. As tentativas de regulamentação e consolidação da função social propedêutica, que nega o trabalho, a industrialização que demandou a educação instrumental para o trabalho e a redemocratização do Estado que reorganizou a produção em flexível e impõe a formação do novo tipo de trabalhador (KUENZER, 1998) apresentam movimentos contraditórios. Em consonância com estas transformações a concepção técnico-científica de organização adota mecanismos democráticos-participativos. Como alternativa ao projeto educativo burguês, a educação politécnica propõe superar a dualidade estrutural e histórica por meio da formação omnilateral (SAVIANI, 2003). A escola fundamental e média deve guiar-se pelo trabalho como base excelente da educação (PISTRAK, 2005), portanto, deve vincular a vida escolar com a transformação social combinando educação escolar com produção material e promover a auto-emancipação e a emancipação social. Neste contexto, o objetivo geral é analisar a experiência de reorganização do trabalho educativo na constituição do projeto político-pedagógico da escola de ensino médio, identificando perspectivas, limites, possibilidades e resistências. Os objetivos específicos são examinar a evolução do projeto educativo na história sociopolítica e econômica do Brasil, destacando a gestão do trabalho escolar e a formação do jovem para o trabalho; analisar os fundamentos, intencionalidades e práticas que norteiam o projeto político-pedagógico e identificar e analisar os limites, possibilidades e formas de resistência coletiva na gestão do projeto. Optamos como referencial teórico-metodológico pela Teoria Crítica e pelo método de base materialista-histórica. Como instrumento de coleta de dados quantitativos e qualitativos foram aplicados questionários, grupos focais e entrevistas semiestruturadas. Entre os questões levantadas destacamos se escola pública deve seguir o projeto educativo da burguesia – propedêutica – ou deve se pautar na dimensão profissionalizante, instrumental, por atender ao projeto burguês para o setor popular? A escola mineralizada tem conseguido ressignificar diretrizes? O projeto político-pedagógico (PPP) em curso no Liceu do Maracanaú estabelece quatro pilares que reorganizam o trabalho na escola tendo em vista a formação integral do jovem. Esta escola pensa concebe e avalia e na contramão da maioria das escolas, rompe com o formato tradicional de organização do trabalho. As inteligências múltiplas são compreendidas como princípio, os projetos de trabalho como meio para a transformação do saber popular para o saber científico com aplicação prática e social dos conteúdos no desenvolvimento de competências e habilidades, a organização semestral como meio e a avaliação como monitoramento da aprendizagem. A iniciação cientifica destaca os talentos, melhora os indicadores e apresenta resultados. Este projeto é contraditório, pois os fundamentos e a prática pedagógica reafirmam os princípios liberais e o processo de escolarização excludente. Deste modo, o estudo confirma que é possível reorganizar o trabalho e este se concretiza por intermédio do PPP. Diante destas novas demandas, as escolas se encontram numa encruzilhada e sua funcionalidade é colocada em dúvida. Como prognóstico, apontamos o aprofundamento da crise da educação, da formação do jovem e da sociedade. Urge investir nas contradições inerentes ao sistema, apropriar-se delas para construção do outro, do contrário. Cabe, portanto, aos intelectuais e educadores cumprirem com a sua tarefa.