Orientadores: Marlene Aparecida Schiavinato, Claudia Baptista Haddad / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-09-11T21:06:20Z (GMT). No. of bitstreams: 1 Lima_AnaLuciadaSilva_D.pdf: 355483 bytes, checksum: 9ce9e116731fc53ab23c70ac20c5cf48 (MD5) Previous issue date: 2005 / Resumo: A duração do ciclo de vida foliar determina características distintas nas folhas, que são relevantes para a sobrevivência da planta em diferentes habitats. Tem sido verificado que as espécies perenifólias apresentam mecanismos mais eficientes de conservação de nitrogênio (N) em relação às espécies decíduas. Esses mecanismos são: eficiência de reaproveitamento de nitrogênio (ERN), proficiência de reaproveitamento de nitrogênio (PRN) e eficiência do uso de nitrogênio (EUN). Segundo um dos paradigmas da ecologia vegetal, as espécies crescendo em ambientes oligotróficos têm maior eficiência de reaproveitamento de nutrientes em relação a espécies características de ambientes eutróficos. A PRN em espécies adaptadas a solos poço férteis é maior do que a de espécies de solos mais férteis. Plantas com longo ciclo de vida foliar possuem maior EUN do que plantas com folhas menos longevas e esta eficiência aumenta com o decréscimo da concentração de nutriente no solo. Espécies perenifólias apresentam maior longevidade foliar do que as decíduas e maior concentração de fenóis. Por outro lado, a concentração de taninos costuma ser maior nas folhas de espécies decíduas. É visto também que as espécies com folhas mais longevas possuem menor concentração de N total, menor concentração de compostos nitrogenados e maior massa foliar específica (MFE). O objetivo deste trabalho foi verificar se as observações encontradas na literatura, comparando espécies perenifólias e decíduas, aplicam-se também às espécies semidecíduas (Hymenaea courbaril - sem FSN e Lonchocarpus guilleminianus ¿ com FSN) e decíduas (Enterolobium contortisiliquum ¿ com FSN e Peltophorum dubium - sem FSN) encontrada em uma Mata Estacional Semidecídua remanescente da Mata Atlântica. As plantas foram cultivadas em casa de vegetação, em vasos contendo solo de local onde as espécies são encontradas na mata, enriquecido ou não com N. Plantas de H. courbaril e P. dubium também foram cultivadas em areia. Houve decréscimo na concentração de clorofila total com o avanço da idade foliar nas quatro espécies. As ERN, PRN e EUN decresceram com o aumento da concentração de N no solo. Espécies com FSN apresentaram menor ERN, PRN e EUN em relação às espécies sem FSN. Plantas cultivadas em areia tiveram maiores ERN, PRN e EUN. Os resultados mostraram uma relação inversa entre os parâmetros de ERN, PRN, EUN e presença de FSN e fertilidade do solo. Os resultados obtidos corroboram os da literatura, já que as espécies com folhas mais longevas apresentaram concentrações maiores de fenóis e maior MFE, menores de taninos, nitrato, proteínas, aminoácidos, clorofila e N total / Abstract: Depending on the leaf life span, the leaves show distinct characteristics, which are relevant to the survival of the plant in different habitats. It has been noticed that the evergreen species show more efficient mechanisms of Nitrogen (N) conservation. These mechanisms are related to N Resorption Efficiency (NRE), N Resorption Proficiency (NRP) and N Use Efficiency (NUE). According to one of the paradigms of plant ecology, species growing in oligotrophic environments are more efficient in nutrient resorption than species from eutrophic environments. It is well known that the NRP in species adapted to soils which are not very fertile, is higher than in species of fertile soils. Plants with long leaf life span have higher NUE than plants with shorter leaf life span and the NUE increases with the decrease of nutrient in the soil. Since the evergreen species present longer leaf life span than the deciduous, their leaves present higher concentration of phenolic compound. On the other hand, the concentration of tannins is usually higher in leaves of deciduous species. It is also known that the long leaf life species have lower concentration of nitrogen compounds and higher Specific Leaf Mass (SLM). The objective of this study was to verify if the observations found in literature, comparing evergreen species to deciduous species, are also applied to the semi deciduous species (Hymenaea courbaril - without SNF and Lonchocarpus guilleminianus ¿ with SNF) and deciduous species, (Enterolobium contortisiliquum ¿ with SNF and Peltophorum dubium - without SNF) of a semi deciduous tropical forest, remnant of the Atlantic Forest. The plants were grown in a greenhouse; in pots filled with soil from their natural environment, enriched or not with N. Plants of H. courbaril and P. dubium were also grown in sand. The results obtained confirm the observations cited in the literature, since the species with longer leaf life span presented higher SLM and concentrations of phenolic compounds, lower concentrations of tannins, nitrate, total proteins, total free amino acids, chlorophyll total), total N. There was a fall in the concentration of total chlorophyll with the advance of leaf age in the four species. The NRE, NRP and NUE decreased with the increase of N concentration in the soil. Species with SNF presented lower NRE, NRP and NUE if compared to species without SNF / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

Made available in DSpace on 2016-01-26T18:56:33Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 190502 bytes, checksum: 5752f80c9f704bcfdb2fab5cb3f0b55c (MD5) Previous issue date: 2008-08-27 / This work evaluated the behavior of phosphorus sources: Arad phosphate, Alvorada phosphorite and Triple Superphosphate in two soils a sandy and a clay 70% basis saturation in the natural acidity condition. The experimental outlining was totally randomized in a factorial scheme (2x2x3x4), being: two soils; three phosphate fertilizer sources; and four doses (0, 100, 200 and 400 Kg ha-1), with four repetitions. The results were submitted to the analysis variation, being taken the retrogression one, adjusting the equations and using as a criterion to the statistical pattern choice the significative F tests from 1 to 5%, and magnitude of determination coefficients. The phosphate fertilizers raised the calcium and the phosphorus proportions in the sand and in the sand-clay soils, both in presence and in absence of liming. The arad, applied in high doses in the acid soils, changed the pH of the sandy and the clay soils were noticed in the treatments that received an Alvorada Phosphorite application, and the highest proportions of the Triple Superphosphate and the Arad showed intermmediate proportions of available phosphorus. / Este trabalho avaliou o comportamento das fontes de fósforo: Arad, Fosforita Alvorada e Superfosfato Triplo em dois solos. - um arenoso e outro argiloso. -, na condição de acidez natural e, após a correção, atingir saturação por bases a 70%. O delineamento experimental utilizado foi inteiramente casualizado, com esquema fatorial (2x2x3x4), sendo: dois solos; três fontes de fertilizantes fosfatados e quatro doses (0, 100, 200 e 400 Kg há -1), com quatro repetições. Os resultados foram submetidos à análise de variância, sendo adotada a análise de regressão, ajustando-se as equações, e tendo-se como critério para escolha do modelo estatístico os testes F significativo a 1 a 5%, e (magnitude dos coeficientes de determinação). Os fertilizantes fosfatados elevaram os teores de cálcio e fósforo nos solos arenoso e argiloso na presença e ausência de calagem. O Arad, aplicado em doses elevadas nos solos ácidos, alterou o pH dos solos arenoso e argiloso. Os menores teores de fósforo disponível no solo foram observados nos tratamentos que receberam a aplicação de Fosforita Alvorada, e os maiores teores para o Superfosfato Triplo e o Arad apresentaram teores intermediários de fósforo disponível.

Made available in DSpace on 2016-07-18T17:51:15Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 190502 bytes, checksum: 5752f80c9f704bcfdb2fab5cb3f0b55c (MD5) Previous issue date: 2008-08-27 / This work evaluated the behavior of phosphorus sources: Arad phosphate, Alvorada phosphorite and Triple Superphosphate in two soils a sandy and a clay 70% basis saturation in the natural acidity condition. The experimental outlining was totally randomized in a factorial scheme (2x2x3x4), being: two soils; three phosphate fertilizer sources; and four doses (0, 100, 200 and 400 Kg ha-1), with four repetitions. The results were submitted to the analysis variation, being taken the retrogression one, adjusting the equations and using as a criterion to the statistical pattern choice the significative F tests from 1 to 5%, and magnitude of determination coefficients. The phosphate fertilizers raised the calcium and the phosphorus proportions in the sand and in the sand-clay soils, both in presence and in absence of liming. The arad, applied in high doses in the acid soils, changed the pH of the sandy and the clay soils were noticed in the treatments that received an Alvorada Phosphorite application, and the highest proportions of the Triple Superphosphate and the Arad showed intermmediate proportions of available phosphorus. / Este trabalho avaliou o comportamento das fontes de fósforo: Arad, Fosforita Alvorada e Superfosfato Triplo em dois solos. - um arenoso e outro argiloso. -, na condição de acidez natural e, após a correção, atingir saturação por bases a 70%. O delineamento experimental utilizado foi inteiramente casualizado, com esquema fatorial (2x2x3x4), sendo: dois solos; três fontes de fertilizantes fosfatados e quatro doses (0, 100, 200 e 400 Kg há -1), com quatro repetições. Os resultados foram submetidos à análise de variância, sendo adotada a análise de regressão, ajustando-se as equações, e tendo-se como critério para escolha do modelo estatístico os testes F significativo a 1 a 5%, e (magnitude dos coeficientes de determinação). Os fertilizantes fosfatados elevaram os teores de cálcio e fósforo nos solos arenoso e argiloso na presença e ausência de calagem. O Arad, aplicado em doses elevadas nos solos ácidos, alterou o pH dos solos arenoso e argiloso. Os menores teores de fósforo disponível no solo foram observados nos tratamentos que receberam a aplicação de Fosforita Alvorada, e os maiores teores para o Superfosfato Triplo e o Arad apresentaram teores intermediários de fósforo disponível.

La symbiose entre les légumineuses et les Rhizobiacées est la source d’azote fixé la plus importante pour le bon fonctionnement des écosystèmes naturels et agricoles. Très étudiée chez des légumineuses modèles, certains aspects de cette interaction restent peu connus ; c’est le cas des mécanismes génétiques et fonctionnels qui contrôlent la spécificité hôte-symbiote. Il n’y a que peu d’études globales consacrées à ce phénomène, et les gènes symbiotiques sont très peu connus chez les espèces non-modèles. Dans ce contexte, nous avons étudié un cas de changement de spécificité symbiotique remarquable chez des espèces phylogénétiquement proches du genre Lupinus (Fabacées). Tout d’abord, la reconstruction et l’analyse de génomes chloroplastiques complets a permis de camper le cadre évolutif de la symbiose en générant de nouveaux marqueurs d’intérêt pour clarifier la phylogénie et l’évolution des lupins. A partir d’une expérimentation d’inoculation croisée impliquant trois espèces de lupins méditerranéens et deux souches compatibles et incompatibles de Bradyrhizobium, une approche RNA-Seq a permis de produire les premiers nodulomes de lupin et d’identifier les gènes symbiotiques. L’analyse des gènes différentiellement exprimés a montré que la spécificité symbiotique affecte non seulement la voie de signalisation et de régulation de la symbiose, mais également une diversité de voies métaboliques associées. Enfin, l’étude de la dynamique évolutive et fonctionnelle de quelques gènes a mis en évidence l’impact et l’importance des phénomènes de duplication aux différents niveaux de la cascade génétique symbiotique. / Legumes-Rhizobia symbiosis is the most important fixing nitrogen source for the good functioning of both natural and agricultural ecosystems. Although, it is extensively studied in model legumes, some aspects of this interaction remain unclear, such as the genetic and functional mechanisms controlling the host-symbiont specificity. Large scale studies of this process are scarce and symbiotic genes are not well described in non-model species. In this context, the effect of symbiotic specificity was investigated in phylogenetically close relative species belonging to the Lupinus genus (Fabaceae). First, the reconstruction and analysis of complete chloroplast genomes allowed us to generate new and useful markers for clarifying the Lupinus phylogeny in order to lighten the evolutionary context of the symbiosis. Following a cross-inoculation experiment of three Mediterranean lupine species with two compatible or incompatible Bradyrhizobium strains, a RNA-Seq approach allowed the reconstruction of the first lupine nodulomes and the identification of lupine symbiotic genes. The analysis of differentially expressed genes revealed that the symbiotic specificity affects not only the signalling and regulatory symbiotic pathways, but also diverse associated metabolic pathways. Finally, evaluating the evolutionary and functional dynamics of genes highlighted the importance of gene and genome duplication events at different steps of the symbiotic genetic pathway.

I Svappavaara har förhöjda halter av uran med avseende på löst fas påträffats i det vatten sombräddas från industriområdet. Halterna av uran överstiger Havs och vattenmyndighetensbedömningsgrunder för utsläpp av särskilt förorenande ämnen till sötvatten. LKAB måstedärför minska utsläppen av uran till recipienten och utvärderar därför hur detta bör utföras.Detta examensarbete utfördes som en del av detta projekt för LKAB och skrevs på distans frånLuleå Tekniska Universitet. Tidigare studier som LKAB utfört har funnit att halten uran med avseende på löst fas iprocessvattnet minskar inom Svappavaaras processvattensystem innan bräddning, vilket tyderpå att fastläggning av uran sker, men var eller hur har inte kunnat beskrivas. LKAB hartillhandahållit data för lösta halter från sitt regelbundna kontrollprogram från perioden 2016-2021 då provtagning utfördes ungefär en gång per månad. Data har kompletterats som en delav examensarbetet och en provtagningsplan för vatten (löst och ofiltrerat), suspenderat materialoch fast material inom Svappavaaras processvattensystem har tagits fram. Samtliga proveranalyserades för halter av 72 grundämnen vid ALS Scandinavias laboratorium i Luleå.Elektrisk konduktivitet, pH, alkalinitet samt anjoner analyserades av LKABs internamiljölaboratorium, temperatur mättes i fält. Haltdata användes för att studerakoncentrationsförändringar mellan provpunkterna och mellan fast respektive löst fas.Förändring i koncentration studerades sedan för att identifiera processteg där en tydligfasförändring sker. Provtagningen bidrog inte med tillräcklig information för att verifiera ettexakt processteg där uran minskar med avseende på löst fas samtidigt som det ökar i fast fas. Data bekräftar att ingående uran till Svappavaaras processvattensystem är i löst- eller kolloidalfas och inte suspenderad- eller fast fas. Samtidigt kan en massbalans beräknad medmodellerade flöden påvisa att den totala ingående mängden uran är något högre än denutgående. Massbalansen är utförd för både fasta och lösta faser. Uran i löst fas korrelerar medalkalinitet och i viss grad med temperatur samt pH inom Svappavaaras processvattensystem. Modellering av SI (Saturation Index), aktiviteter för de analyserade grundämnena och vanligtförekommande mineral har utförts och visar att inga rena uranmineral sannolikt bildas inomprocessen. Mineral som gips skulle enligt modellerade data kunna bildas i anrikningssandenoch uran kan i vissa fall samutfälla med gips. Vid en kort SEM session kunde korn avkalciumsulfat identifieras i anrikningssanden, utan mätbara halter av uran. Modellering ochanalys av data har utförts i Microsoft Excel, PhreeqC Interactive och The Geochemist’sWorkbench. / In Svappavaara elevated dissolved concentrations of uranium have been found in the processwater that is being discharged from the industry area. The uranium concentrations areelevated compared to the standards set by the Swedish Sea and Water authority, whichgoverns the assessment criteria for release of particularly polluting substances to sweet water.For that reason, LKAB must decrease their release of dissolved uranium to their recipient andare evaluating how this is best done. This thesis is written as a part of that work for LKABand is written from Luleå Technical University. Earlier studies performed by LKAB has shown that the concentration of uranium leavingtheir system is lower than the one entering it with respect to dissolved phase only. But whythis is the case and where inside the process the uranium is stuck has not been possible todescribe, which is the aim of this project. LKAB has distributed data for dissolved phasesfrom their regular control sampling between the years 2016-2021, which is sampled monthly.This data was supplemented as a part of this project and a sampling plan was made for water(dissolved and unfiltered), suspended and solid material within Svappavaara process system.All samples where chemically analysed for 72 elements at ALS Scandinavia’s laboratory inLuleå. Electrical conductivity, pH, alkalinity and anions were analysed at the internalenvironmental lab at LKAB, temperature was measured in the field. The data was then usedto study and compare the difference in concentration between solid and dissolved phases toidentify a step in the process where a change is shown. However, the sampling was notsufficient to verify an exact step in the process where a dissolved phase decreases while asolid increases. The sampled data could however show that the uranium entering the process in Svappavaarawas in true dissolved phase or colloidal and not suspended or solid. A mass balance based onmodelled flows shows that the total amount of uranium entering the system is slightly higherthan the one leaving it. The mass balance is done for both dissolved and solid phases.Uranium has also in the dissolved phase been strongly correlated to alkalinity and to a degreealso temperature and pH within the process. Modelling of saturation indices (SI), activities for analysed elements and commonlyoccurring minerals has also been done, which shows that no pure uranium minerals should beformed within the Svappavaara process. However, minerals such as gypsum could accordingto the model precipitate within the tailings and uranium could in some cases coprecipitatetogether with gypsum. At a short SEM session calcium-sulphate grains could be identifiedwithin the tailings, without traceable uranium concentrations. Modelling and the analysis ofdata has been done within Microsoft Excel, PhreeqC interactive and The Geochemist’sWorkbench.

L’architecture du système racinaire des légumineuses est déterminée par la croissance des racines et leur capacité à former des racines latérales et des nodosités symbiotiques fixatrices d’azote en fonction des conditions environnementales. Chez la légumineuse modèle Medicago truncatula, nous avons mis en évidence que les phytohormones gibbérellines (GAs) et leur voie de signalisation – médiée par trois protéines MtDELLAs présentant des profils d’expression redondants – jouent un rôle clé dans la régulation du développement du système racinaire. En conditions non-symbiotiques, les GAs régulent négativement la croissance racinaire en réprimant l’activité méristématique et l’élongation cellulaire, et inhibent la formation des racines latérales. En conditions symbiotiques, le rôle des GAs et de leur voie de signalisation est double : au niveau de l’épiderme, les protéines MtDELLAs régulent positivement l’infection par les bactéries symbiotiques Rhizobia en interagissant de façon directe avec la voie de signalisation des facteurs Nod bactériens. Au niveau du cortex, les GAs régulent négativement l’organogénèse des nodosités. Les phytohormones cytokinines (CKs) et leur récepteur MtCRE1 étant essentiels pour initier la nodulation, l’interaction entre les voies de signalisation GA et CK a été analysée en parallèle. Les CKs régulent le niveau de GAs bioactives en modulant l’expression des gènes de leur métabolisme de manière dépendante du récepteur aux CKs MtCRE1. Réciproquement, les GAs régulent les gènes du métabolisme CK et le niveau de CKs bioactives de manière dépendante des MtDELLAs. Par ailleurs, une forme activée de MtDELLA complémente partiellement le phénotype de nodulation du mutant cre1 et lie le promoteur de MtCRE1, indiquant que les voies de signalisation GA et CK régulent la nodulation en étroite association. / Legume root system architecture is determined by both root growth and their ability to form lateral roots and nitrogen-fixing symbiotic nodules, depending on environmental soil conditions. In the model legume Medicago truncatula, we have shown that the phytohormones gibberellins (GAs) and their signaling – involving three MtDELLA proteins with redundant expression patterns – play a crucial role in the regulation of the root system development. In non-symbiotic conditions, GAs negatively regulate root growth through the repression of meristematic activity and cell elongation, and inhibit lateral root formation. In symbiotic conditions, GA and their signaling pathway play a dual role: in the root epidermis, MtDELLA proteins positively regulate infection by symbiotic bacteria Rhizobia, by directly interacting with the bacterial Nod factor signaling pathway. In the root cortex, GAs negatively regulate nodule organogenesis. The phytohormones cytokinins (CKs) and their receptor MtCRE1 being essential for the initiation of nodulation, we additionally analyzed the crosstalk between GA and CK signaling. CKs regulate the bioactive GA pool, controlling the expression of GA-metabolic genes, depending on the MtCRE1 receptor. In turn, GAs regulate CK-metabolic genes and the bioactive CK pool, depending on MtDELLAs. In addition, a dominant version of a MtDELLA partially complements the nodulation phenotype of the cre1 mutant and binds to the MtCRE1 promoter. These results indicate that GA and CK signaling pathways closely interact to regulate nodulation.

Nitrogen (N)-fixing trees can both mitigate climate change, by relieving N limitation of plant growth which promotes carbon dioxide (CO²) sequestration in plant biomass, and exacerbate climate change, by stimulating nitrification and denitrification which promotes nitrous oxide (N²O) emissions from soils. The balance between the negative radiative forcing (CO² sequestration in plant biomass) and positive radiative forcing (N²O emissions from soils) of N-fixing trees is unresolved. In this thesis I use a sequence of theoretical and empirical approaches to investigate the influence of N-fixing trees on CO² sequestration by forests and N²O emissions from forest soils, i.e., the net CO²-N²O effect of forests. The first chapter establishes a basis for the N²O effect of N-fixing trees with a meta-analysis, to accompany existing meta-analyses of the CO² effect of N-fixing trees. Chapter one demonstrates that N- fixing trees significantly increase N²O emissions from forest soils relative to non-fixing trees. The second chapter explores the controls and potential global importance of the net CO²-N²O effect of N-fixing trees using a theoretical ecosystem model. The third chapter explores the net CO²-N²O effect of N-fixing trees under manipulations of these controls with a field experiment paired with a modified version of the theoretical ecosystem model from the second chapter. Together, chapters two and three suggest that the net CO²-N²O effect of N-fixing trees is controlled by N limitation of plant growth and the extent to which N-fixing trees can regulate N fixation: N-fixing trees mitigate climate change relative to non-fixing trees under N limitation of plant growth, but N-fixing trees that cannot regulate N fixation exacerbate climate change relative to non-fixing trees under non-N limitation of plant growth. The fourth chapter represents the ecological mechanisms studied in chapters one, two and three in a land model: LM4.1-BNF is a novel representation of biological N fixation (BNF) and an updated representation of N cycling in the Geophysical Fluid Dynamics Laboratory Land Model 4.1 (LM4.1). LM4.1-BNF includes a mechanistic representation of asymbiotic BNF by soil microbes, the competitive dynamics between N-fixing and non-fixing plants, N limitation of plant growth, and N2O emissions from soils. Together these chapters elucidate the influence of N-fixing trees on the capacity of forests to mitigate and exacerbate climate change and establish a framework to analyse and project the trajectory of the net CO²-N²O effect of forests under global change.

En cas de carence azotée, les légumineuses sont capables de mettre en place une symbiose avec des bactéries du sol fixatrices d’azote appelées rhizobia. Cette symbiose a lieu dans un organe appelé nodosité où les bactéries sont endocytées et appelées bactéroïdes. Certains clades de légumineuses imposent un processus de différenciation à leurs bactéroïdes qui agrandissent considérablement et deviennent polyploïdes, menant à des morphotypes bactériens allongés ou sphériques. Au cours de cette thèse, j’ai étudié la différenciation des bactéroïdes de Bradyrhizobium spp. en association avec Aeschynomene spp.. Les bactéroïdes de ces plantes présentent des degrés de différenciation distincts qui dépendent de l’espèce hôte. Mes données suggèrent que les bactéroïdes les plus différenciés sont aussi les plus efficaces. J’ai cherché à savoir quels facteurs procaryotes pourraient être impliqués dans les adaptations des bactéroïdes au processus de différenciation et à leurs divers hôtes, le tout en lien avec cette différence d’efficacité symbiotique au travers d’approches globales sans a priori de type -omiques. Les conditions considérées sont des bactéroïdes de différents morphotypes et des cultures libres de référence. Les fonctions activées en conditions symbiotiques ont été identifiées, ainsi que les gènes spécifiques d’un hôte donné. Des analyses fonctionnelles des gènes d’intérêt ont également été menées. Les mutants bactériens n’ont toutefois pas présenté de phénotype symbiotique drastique, montrant ainsi l’existence de réseaux de gènes complexes menant à la résilience des génomes de rhizobia. / In case of nitrogen starvation, legume plants establish a symbiotic interaction with nitrogen-fixing soil bacteria called rhizobia. This interaction takes place in nodules where the symbionts are internalized and become bacteroids. Some legume clades also impose a differentiation process onto the bacteroids which become enlarged and polyploid, leading to elongated or spherical morphotypes. During my PhD work, I have studied bacteroid differentiation of Bradyrhizobium species in association with Aeschynomene spp.. These bacteroids display distinct differentiation levels depending on the plant host, and my analyses suggest that the most differentiated ones are also the most efficient. I investigated the bacterial factors potentially involved in the adaptations to differentiation and host-specificity, and related to the higher efficiency of the most differentiated bacteroids using global-omics approaches without a priori. The analyzed conditions were bacteroids of distinct morphotypes and free-living reference cultures. Activated functions under symbiotic conditions were identified, as well as host-specific ones. Functional analyses were performed on genes of interest. However, the bacterial mutants did not display drastic symbiotic phenotypes, showing the existence of complex gene networks leading to high resilience of rhizobial genomes.

Au cours des dernières années, des progrès ont été faits dans le domaine papetier. De plus, le développement de nouveaux matériaux biosourcés a fait l’objet de nombreux sujets de recherche. L’élaboration de fixateurs de colorants alimentaires anioniques à base de chitosane destinés à l’industrie papetière, s’inscrit donc dans ce contexte R & D. Ce projet, proposé par la société Colorey et mené à bien en collaboration avec le laboratoire d’Ingénierie des Matériaux Polymères (IMP, UMR 5223), a consisté en l’utilisation de chitosane (unique polycation naturel) tel quel pour la coloration en surface du papier, ou modifié avec le chlorure de glycidyltriméthylammonium (GTMAC) sous la forme de chitosane quaternarisé (Chi-GTMAC), pour la coloration dans la masse. Ce dernier procédé de coloration requiert un pH neutre ou légèrement alcalin, ce qui est incompatible avec la solubilisation du chitosane, qui nécessite un milieu aqueux acide. C’est pourquoi le Chi-GTMAC, comportant des fonctions triméthylammonium comme charges positives indépendantes du pH, a été mis au point. La stabilité thermique et la solubilité à tout pH de chaque échantillon, ont été évaluées afin de déterminer leur capacité à supporter ou non les températures de séchage du processus papetier, et leur potentiel d’utilisation au sein du pulpeur pour la coloration dans la masse. Puis, l’efficacité de certains dérivés à colorer la pâte et à fixer le colorant a été étudiée à l’aide d’un plan d’expérience. Le chitosane a, quant à lui, été testé en solution aqueuse acide comme agent fixateur pour la coloration de surface du papier préformé / Over the past years, progresses have been achieved in the field of the paper industry. Moreover, the development of biosourced materials has been studied under intense investigations.The elaboration of chitosan-based fixing agents of anionic food dyes intended to paper industry is in line with this R & D context. This project, proposed by the company Colorey and carried out in collaboration with IMP laboratory (UMR 5223), consisted in using chitosan (the only natural polycation) as such for the surface dyeing of paper or, modified with the glycidyltrimethylammonium chloride (GTMAC) as quaternized chitosan (Chi-GTMAC), for the mass dyeing of the pulp. This last process required a neutral or slightly alkaline pH within the pulper, which cannot allow the solubilization of chitosan. Hence, chitosan was derivatized into Chi-GTMAC, bearing trimethylammonium moieties as pH-independent functional groups. The thermal stabilities and the aqueous solubilities as a function of pH of these derivatives were investigated in order to determine whether they could support the drying temperature of the papermaking process or whether they could be used within the pulper for mass coloration. Then, the efficiency of some of the obtained derivatives to color the pulp and to fix dyes was determined thanks to a designed of experiments. Chitosan, for its part, has been tested as fixing agent for surface coloration of paper

The nitrogen fixing bacteria (NFB) and phosphate solubilizing bacteria (PSB) are used widely for producing of microbiological fertilizers. This study aims to seek nitrogen-fixing and phosphate-solubilizing bacteria strains to add to the collection of candidate strains for producing single and multi-function microbiological fertilizers. From 40 soil samples of 8 fields for cultivating rice, medicinal plants and vegetables, 15 NFB strains and 12 PSB strains were isolated and determined the ability of fixing nitrogen and solubilizing inorganic phosphate compound through creation of NH₄⁺ and PO₄⁻ in culture medium. Among 15 NFB strains, the fixing nitrogen activities of 7 strains were much higher than the remaining strains, including NFBR3, NFBV2, NFBM5, NFBM3, NFBM1, NFBV5 and NFBR2 with NH₄⁺ concentration 18.85 mg/l, 18.41 mg/l, 17.32 mg/l, 16.19 mg/l, 15.49 mg/l, 12.83 mg/l and 12.57 mg/l, respectively Among 12 PSB strains, The ability of solubilizing phosphate of 5 strains were higher than the others, including PSBM2, PSBR1, PSBV1, PSBR5 and PSBR3 with PO₄⁻ concentration 14.49 mg/l, 11.83 mg/l, 11.33 mg/l, 10.65 mg/l, 10.37 mg/l, respectively. 3 NFB strains (NFBR3, NFBV2, NFBM5) and 3 PSB strains (PSBM2, PSBR1, PSBV1) with higher activity were identified by 16S-rDNA sequence analysis and comparing to some homologous sequences in genbank. The results showed that NFBR3 was identified as Azotobacter vinelandii, NFBV2 as Azopirillum brasilense, NFBM5 as Azotobacter chroococum, PSBM2 and PSBV1 as Pseudomonas fluorescens and PSBR1 as Bacillus subtilis. / Vi khuẩn cố định nitơ (NFB) và vi khuẩn phân giải phosphate (PSB) được sử dụng rộng rãi trong sản xuất phân bón vi sinh. Nghiên cứu này nhằm mục đích tìm kiếm các chủng vi khuẩn cố định nitơ và hòa tan phosphate, bổ sung vào bộ sưu tập các chủng dự tuyển cho sản xuất phân bón vi sinh đơn và đa chức năng. Từ 40 mẫu đất của 8 ruộng trồng lúa, cây dược liệu và rau màu, 15 chủng NFB và 12 chủng PSB đã được phân lập và xác định khả năng cố định nitơ và phân giải phosphate vô cơ thông qua sự tạo thành NH₄⁺ và PO₄⁻ trong môi trường nuôi cấy. Trong số 15 chủng NFB, có 7 chủng có hoạt tính cố định nitơ cao hơn những chủng còn lại, bao gồm các chủng NFBR3, NFBV2, NFBM5, NFBM3, NFBM1, NFBV5 và NFBR2 với nồng độ NH₄⁺ lần lượt là 18.85mg/l, 18.41 mg/l, 17.32 mg/l, 16.19 mg/l, 15.49 mg/l, 12.83 mg/l và 12.5 7mg/l. Trong số 12, có 5 chủng có khả năng phân giải phosphate cao hơn những chủng khác, bao gồm chủng PSBM2, PSBR1, PSBV1, PSBR5 và PSBR3 với nồng độ PO₄⁻ lần lượt là 14.49 mg/l, 11.83 mg/l, 11.33 mg/l, 10.65 mg/l và 10.37 mg/l. Các chủng NFB và PSB này đều xuất hiện ơ các mẫu đất trồng lúa, đất trồng cây dược liệu và đất trồng rau màu. 3 chủng NFB và 3 chủng PSB với hoạt tính cố định nitơ và phân giải phosphate cao hơn được định loại bằng phân tích trình tự gen 16S-rDNA và so sánh với một số trình tự tương đồng trong genebank. Kết quả chỉ ra rằng chủng NFBR3 được định danh là Azotobacter vinelandii, chủng NFBV2 là Azopirillum brasilense, chủng NFBM5 là Azotobacter chroococum, chủng PSBM2 và chủng PSBV1 là Pseudomonas fluorescens và chủng PSBR1 là Bacillus subtilis.