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Coupel-Ledru, Aude. "Déterminisme physiologique et génétique de l'utilisation de l'eau chez la vigne". Thesis, Montpellier, SupAgro, 2015. http://www.theses.fr/2015NSAM0020.
Pełny tekst źródłaIn Mediterranean regions, water scarcity associated with climate change particularly threatens the sustainability of viticulture. Breeding grapevine for reduced water use and maintained production is therefore of major interest. This requires a comprehensive knowledge of the plant physiological responses to drought. In this study we focused on the determinism of transpiration rate as a key trait regulating water status in plant tissues, and on its relationship with water-use efficiency (WUE). We used a F1 progeny from a cross between cultivars Syrah and Grenache and combined powerful phenotyping tools on potted plants submitted to either well-watered or mild deficit conditions with quantitative genetics (for QTL detection) and physiological experiments. Analysis of the genetic control of water status maintenance in the plant, more or less efficient under soil water deficit (i.e. iso- or anisohydric), revealed a dual physiological determinism with a key role for plant hydraulic conductance beside that of stomatal control of transpiration. An indirect role of abscisic acid on stomatal conductance was also evidenced, mediated by the downregulation of leaf hydraulic conductance, with a genetic variability which correlated with genetic variation in iso- or aniso-hydric behaviour. We then revealed wide genetic variations in nocturnal transpiration, which correlated with variations in water use efficiency, and identified corresponding genetic and physiological determinants. In a final switch to the field, we showed consistency between QTLs detected for daytime WUE in pots and in the vineyard. Beyond the potential interest of the QTLs detected in this study for breeding prospects, this work demonstrated the benefits of quantitative genetics to shed light on ecophysiological and physiological processes
Pilloni, Raphael. "AGRONOMICAL AND PHYSIOLOGICAL STUDY OF THE RESPONSE OF SORGHUM AND PEARL MILLET CROPS TO HIGHER SOWING DENSITY IN THE SEMI-ARID TROPICS. ASSESSEMNT OF THE OPPORTUNITY FOR SUSTAINABLE INTENSIFICATION AND CONSEQUENCE FOR THE TRANSPIRATION RESPONSE TO EVAPORATIVE DEMAND OF THE CROPS". Electronic Thesis or Diss., Université de Montpellier (2022-....), 2022. http://www.theses.fr/2022UMONG051.
Pełny tekst źródłaIn the semi-arid tropics, sorghum and pearl millet or key source of income and calories. Sustainable intensification is therefore needed to ensure food security. These two cereals are largely grown in smallholder farming system and cultivated at low density, opening an avenue to increase yield through this agronomic management. Through field and lysimetric trials carried out in India and Senegal this work showed the possibility to increase significantly, the biomass and grain yield in both species, with the same irrigation regime and fertilization. We highlighted a lowering of the vapour pressure deficit (VPD) in the canopies of high density, resulting in an increase in water use efficiency of the crops. While both crops responded positively to increased density, there were also large specie differences in the genotypic variation of the response to density, namely a strong genotype x density interaction in sorghum for biomass and WUE, but none in pearl millet. The genotypic variation in the degree of WUE response found in sorghum and its link with biomass accumulation led to investigate putative differences in the transpiration response of the crops to the evaporative demand. We tested this hypothesis outdoors with canopy-grown sorghum plants in field and lysimeter experiments. The response of the evapotranspiration was measured against the evaporative demand. This response was linear and, with WUE, showed large genetic variation. WUE was surprisingly higher in genotypes with the highest transpiration response to the evaporative demand (Penman-Monteith). These genotypes were also those that allowed maximum light penetration into the canopy. This work opens the door to intensification, in the short term by increasing sowing density in drylands using sorghum and pearl millet cultivars that show a strong response to density, and in the medium term by selecting sorghum cultivars adapted to high density
Bonhomme, Ludovic. "Protéome foliaire et efficience d'utilisation de l'eau chez le peuplier". Thesis, Orléans, 2009. http://www.theses.fr/2009ORLE2011/document.
Pełny tekst źródłaIn the actual climate change context, the cultivated varieties will have to cope with the expected environmental modifications. In poplar, the breeding of genetic ressources able to grow with lower water costs becomes therefore, an essential criterion that can be evaluated from water-use efficiency (WUE). In order to assess the interest to develop a breeding program based on WUE, it was agreed to judge if the genetic variation of WUE observed on young cuttings, were still expressed on trees cultivated in poplar plantation on contrasted soils. In addition, in order to initiate a study of the molecular determinism of WUE, we evaluated the degree of genetic variation in the leaf proteome of eight poplar genotypes contrasted for their WUE and cultivated under varied water supply. Our work evidenced consistent genetic variations of WUE in poplars cultivated in a commercial plantation. However, the type of cultivated soil modified considerably the genotypic ranking, whereas ranking established on the most favourable soils for poplar growth, remained comparable with the one described previously in greenhouse. Our experiments also validated the possibility of distinguishing genotypes contrasted for WUE from their leaf proteome. We showed that leaf proteome of eight poplar genotypes differing by their WUE displayed consistent genetic variations in their drought response and that there were relationships between leaf protein abundances and genetic variations of WUE
Bonhomme, Ludovic Brignolas Franck. "Protéome foliaire et efficience d'utilisation de l'eau chez le peuplier". S. l. : S. n, 2009. ftp://ftp.univ-orleans.fr/theses/ludovic.bonhomme_1655.pdf.
Pełny tekst źródłaMonclus, Romain. "Efficience d'utilisation de l'eau et tolérance à la sécheresse chez le peuplier". Orléans, 2006. http://www.theses.fr/2006ORLE2012.
Pełny tekst źródłaDagenais, Marie Pierre. "Controverse et conflit sur l'utilisation de l'eau souterraine : l'exemple de Franklin". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24469/24469.pdf.
Pełny tekst źródłaDagenais, Marie-Pierre. "Controverse et conflit sur l'utilisation de l'eau souterraine : l'exemple de Franklin". Master's thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24469/24469.pdf.
Pełny tekst źródłaMa, Jingjing. "La gestion, l'utilisation, la consommation et la représentation de l'eau en Chine". Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB195/document.
Pełny tekst źródłaWe will analyze this topic based on four major scales of observation: macrosocial, mesosocial, microsocial and micro individual. Firstly, in order to understand the context of drinking-water usage and management, we will present the environmental context and the geopolitical importance of water at the international level. We will then demonstrate China's development following a "water crisis" at the national level. Finally, we will present the regional-level example of Guangzhou, along with the solutions to and conflicts within this crisis on a macrosocial scale. "Water management", in terms of quantity and quality, continues to be a particularly important issue on the national and international stage. Secondly, we will examine the changes in the quality and management of running water in Guangzhou. In this second section, we will first show that running water in the region has become undrinkable due to severe pollution stemming from rapid urbanization. On a mesosocial level, we can observe the reactions of and cooperation between various segments of the public and private sector with respect to the production and distribution of running water. In the third section, we will examine the issue on the microsocial scale. Here, we will be focusing on water usage in individuals' daily lives, especially in the context of food and eating habits. We will first describe the changing role and diversity of water usage in the modern urban Chinese household, from historic usage of well-water to various types of commercially produced water. How do individuals select their preferred water source(s) based on the available options? How do they use and transform the meaning of water within the domestic realm? Next, we will analyze the forms of consumption and the representations of drinking water (including running water as well as other types of non-alcoholic water beverages, both flavored and unflavored) within Chinese households in four major Chinese cities: Beijing, Shanghai, Guangzhou, and Chengdu on the microsocial scale and micro individual. In this section, we outline the differences between the habits of more traditional Chinese, adherents of the Chinese philosophy of qi, yin, and yang, and those of more modern, non-traditional Chinese, as well as those in between the two extremes. This section also explores the relationships inherent in Chinese society though the lens of water consumption. Lastly, we address the issue of flavor, especially sugar in non-alcoholic drinks, by outlining the forms, practices, representations, and management of the body in relation to sugar and sweet drinks
Higelin, Pascal. "Salmoniculture et pollution : problèmes liés à l'utilisation de l'eau en élevage piscicole intensif, techniques permettant d'améliorer la qualité de l'eau". Paris 5, 1988. http://www.theses.fr/1988PA05P155.
Pełny tekst źródłaPorcher, Simon. "Choix organisationnels, efficience et équité dans les services publics locaux : le cas du service public de l'eau en France". Paris 1, 2012. http://www.theses.fr/2012PA010074.
Pełny tekst źródłaChamaillard, Sylvain. "Efficience d'utilisation de l'eau chez le peuplier noir (Populus nigra L.) : variabilité et plasticité en réponse aux variations de l'environnement". Phd thesis, Université d'Orléans, 2011. http://tel.archives-ouvertes.fr/tel-00713525.
Pełny tekst źródłaMiller, Novadene. "Développement durable et gestion de l'eau dans la région des cockpits (Jamaïque) : efficience du discours, perception et usages, quelle durabilité ?" Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0377.
Pełny tekst źródłaThis dissertation examines the extent to which the local residents’ perspectives and practices linked to the use of natural resources, such as water, are sustainable. This includes an examination of the role of environmental and non-environmental drivers on water quality within the context of the livelihood systems in the Cockpit Country, Jamaica. The Cockpit Country region is defined by a rounded topography and karst geography, which plays a critical role in the hydrological system. Case study areas consisted of two principal categories: areas with water access points and areas without access points, as water use sources. The research uses an explanatory approach to establish causal linkages between local perspectives and usage of natural resources. New questions include a focus on water usage practices, water security, water access and sustainability within the socio geographic context of livelihood systems
Colin, Jérôme. "Apport de la télédétection optique à la définition d'indicateurs de performance pour l'utilisation de l'eau en agriculture". Université Louis Pasteur (Strasbourg) (1971-2008), 2006. https://publication-theses.unistra.fr/public/theses_doctorat/2006/COLIN_Jerome_2006.pdf.
Pełny tekst źródłaIn this work, we define a new methodology that allows calculating actual evaporation from high resolution remote sensing images to assess the performance of irrigation in cultivated areas. This approach is based on the SEBI concept, visible to near and thermal infrared remote sensing images to derive geometric and radiometric surface properties, and atmospheric boundary layer variables that allow estimating turbulent flux at regional scale. The main advances are: i) the new MSSEBS model allowing to map evaporative fraction and actual evaporation at a high spatial resolution and on a regional extent ; ii) a new methodology to calculate the available energy for turbulent flux (Rn-G0) from the diurnal shape of the ratio of global over net radiation, allowing to calculate actual and potential diurnal evaporation for each pixel; iii) scenarios, sensitivity analysis and information content analysis providing quantitative information on the uncertainty of MSSEBS at field and sub-field scale
Colin, Jérôme Menenti Massimo Li Zhao-Liang. "Apport de la télédétection optique à la définition d'indicateurs de performance pour l'utilisation de l'eau en agriculture". Strasbourg : Université Louis Pasteur, 2007. http://eprints-scd-ulp.u-strasbg.fr:8080/635/01/colin2006_these.pdf.
Pełny tekst źródłaNanakassé, Sidiki. "Sur l'utilisation du gel de silice dans des machines frigorifiques à affinité : adsorption de l'eau et du méthanol". Dijon, 1986. http://www.theses.fr/1986DIJOS070.
Pełny tekst źródłaLeclerc, Annouck. "Faisabilité d'un test de biodiagnostic environnemental basé sur l'utilisation d'un biomarqueur moléculaire de toxicité chez le protozoaire cilié Tetrahymena pyriformis". Saint-Etienne, EMSE, 2005. http://www.theses.fr/2005EMSEA003.
Pełny tekst źródłaThe detection of toxic chemicals constitutes a major stake to reach a good chemical and ecological state of environmental water. Our project aims to exploit the sensitivity of a cellular model to detect in an early and reliable way the presence of cytotoxic concentrations of pollutants. The feasibility of an environmental test, based on the induction of the Metallothionein gene as a molecular toxicity biomarker, was investigated in the ciliate protozoan Tetrahymena pyriformis. The expression of the MT gene was analysed by RT-PCR to check the relevance of this gene as a molecular biomarker of toxicity. Four dangerous pollutants were tested: cadmium, mercury, the nonyl- and the octyl-phenol. Among technologies transposable in the field, genetically transformed organisms constitute powerfull tools to detect weak concentrations of chemicals in the water. We aim to develop T. Pyriformis cells transformed with a constitutive or pollutants-inducible construction. The region of the histone H4I gene was cloned, and the region of the MT gene has to be cloned to develop transgenic cells able to inform about weak concentrations of pollutants in the environmental water
Froux, Fabienne. "Caractéristiques hydrauliques, régulation stomatique et efficience d'utilisation de l'eau de quatre espèces de conifères méditerranéens (Cedrus atlantica, Cupressus sempervirens, Pinus halepensis et Pinus nigra)". Nancy 1, 2002. http://docnum.univ-lorraine.fr/public/SCD_T_2002_0029_FROUX.pdf.
Pełny tekst źródłaMajzoub, Tarek. "La question de l'eau au moyen-orient (aspects juridiques de l'utilisation des cours d'eau a des fins autres que la navigation)". Rennes 1, 1993. http://www.theses.fr/1993REN11006.
Pełny tekst źródłaIn 1988, it was estimated by the center for strategic and international studies that "by the year 2000 water, not oil, will be the dominant resource issue in the middle east". Usage of the euphrates, tigtis, jordan, and nil rivers is continually incressing in line with popular growth, extended urbanisation and irrigation projects of ever greater magnitude. Whilst the management of a ressource so scare in its supply as water is a most daunting taskin its own right, the regional complexities of the middle east add yet another dimension to the problem. The thesis seeks to examine the legal infrastructure and international treaties in the middle east that are currently in existence regarding rights and access to water, what are the policies of the multi-lateral organisations with an interest in this subject, and how best to translate schemes into effective "mechanisms" for the allocation and distribution of international watercourses regarding water in the middle east ("common memorial of mankind")
Frappart, Frédéric. "Hydrologie spatiale :Développement d'applications pour l'utilisation de la télédétection sur les grands bassins fluviaux". Phd thesis, Université Paul Sabatier - Toulouse III, 2005. http://tel.archives-ouvertes.fr/tel-00080744.
Pełny tekst źródłaL'objectif de cette thèse a été de développer de nouvelles applications hydrologiques au moyen des mesures spatiales acquises par différents types de mission satellitaire : altimétrie radar, imagerie satellitaire, gravimétrie spatiale. L'altimétrie spatiale offre la possibilité d'étudier les variations de niveau d'eau des grands fleuves, des lacs et des zones d'inondation, garantissant ainsi une surveillance continue et globale des eaux de surface. Elle donne aussi accès à des produits hydrologiques nouveaux comme le profil hydrologique ou la pente des fleuves. Elle permet en outre de définir des réseaux limnimétriques nivelés, dont les stations peuvent être définis tant sur les fleuves que sur les zones d'inondation, complémentaires des réseaux in-situ. Combinée à l'imagerie spatiale, l'altimétrie satellitaire a été utilisée pour déterminer les variations de volume d'eau dans les grands bassins fluviaux. Ces paramètres revêtent, en effet, une importance fondamentale pour les hydrologues car le premier est à la base des études hydrodynamiques et le second apporte des contraintes sur la répartition des masses d'eau entre zones inondées et réseau hydrographique, avec des applications au transport des sédiments et à la disponibilité des ressources en eau à l'échelle régionale. Des exemples d'utilisation de ces techniques sont présentés pour les bassins amazoniens et du Mékong. La mission de gravimétrie spatiale GRACE, lancée en mars 2002, fournit, quant à elle, les variations spatio-temporelles des stocks d'eaux continentales (eau des sols et manteau neigeux) et de paramètres hydrologiques dérivés comme l'évapotranspiration. Une analyse de l'évolution des stocks d'eau et de neige est présentée à partir des premiers géoïdes mensuels issus de la mission GRACE, aux échelles globale et régionale, ainsi que le calcul du paramètre d'évapotranspiration, à l'échelle du bassin versant. Ces résultats sont comparés à la variation des volumes d'eau de surface obtenue précédemment pour le bassin du Mékong.
Konaté, Nianguiri Moussa. "Diversité interspécifique de l'efficience d'utilisation de l'eau des acacias sahéliens et australiens". Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10044/document.
Pełny tekst źródłaThe main objective of this work was to compare water use efficiency (WUE) among various Australian and Sahelian acacia species using isotope discrimination at leaf level (Δ13Cf) and various methods of measurement. Acacia species exhibited a large inter-specific variability of Δ13Cf. This variability was confirmed by direct leaf gas exchange measurements (intrinsic water use efficiency, Wi) and by measurement at the whole plant level (transpiration efficiency, TE). A large interspecific variability of leaf traits (stomatal density DS, leaf nitrogen concentration %N, specific leaf area SLA, net CO2 assimilation of the saturation Asat, stomatal conductance for water vapor of the saturation gssat) and growth characteristics (root shoot biomass ratio R/S) has also been reported. WUE was controlled for gssat. The hypothesis that the species from arid areas exhibit higher WUE was not confirmed. In contrast, the species from semi-wet area exhibited a higher WUE than those from semi-arid and arid zones
Karimi, Youch Mahmoud. "Amélioration de la distribution de l'eau d'irrigation pour la culture biologique de la tomate de serre". Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/28043/28043.pdf.
Pełny tekst źródłaHaj, Najib Bassel. "Gestion optimale de l'utilisation de l'eau douce et salée pour l'irrigation du coton dans le bassin de l'Euphrate en zone semi-aride". Lille 1, 2007. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2007/50376-2007-147.pdf.
Pełny tekst źródłaFrappart, Frédéric. "Hydrologie spatiale : développement d'applications pour l'utilisation de la télédétection sur les grands bassins fluviaux". Toulouse 3, 2006. http://www.theses.fr/2006TOU30013.
Pełny tekst źródłaRemote sensing can be considered as an important tool for studying the variations of water masses in large river basins due to a homogeneous sampling both in space and time. The objective of this PhD thesis was to develop new hydrological applications using measurements acquired by various types of satellite mission: radar altimetry, satellite imagery, gravimetry from space. Space altimetry is commonly used to study time variations of water level of large rivers, lakes and flooded zones. New hydrological products such as hydrological profiles or river slopes. Levelled limnimetric networks can thus be defined, with gauge stations on the rivers as well as on the flooded zones. Used in combination with imagery from space, satellite altimetry can be used to determine surface water volume variations in large river basins. These parameters are fundamental for hydrologists because hydrological profiles are necessary for hydrodynamic studies and distribution of water volume variations constrains the distribution of water masses between flooded zones and hydrographic network. Examples of use of these techniques are presented for the Amazon and the Mekong basins. In March 2002, a new generation of gravity missions was launched: the Gravity Recovery and Climate Experiment (GRACE) space mission. The objective of GRACE is to measure spatio-temporal variations of the gravity field with an unprecedented resolution and precision, over time scales ranging from a few months to several years. As gravity is an integral of mass, these spatio-temporal gravity variations represent horizontal mass redistributions only to the extent they are assumed to be caused by surface water changes. On time scales from months to decades, mass redistribution mainly occurs inside the surface fluid envelopes (oceans, atmosphere, ice caps, continental reservoirs) and is related to climate variability. An analysis of the evolution of water and snow mass is presented using the first monthly geoids from the GRACE mission, at global and regional scales, as well as the estimation of evapotranspiration rate at basin scale. These results are compared with surface water volume variations previously obtained for the Mekong basin
Elguessabi, Lahcen. "Production et efficience de l'eau chez 3 variétés de Medicago truncatula (M. T. ) en milieu semi-aride sous différents régimes de coupe : action de la fumure NPK". Caen, 1989. http://www.theses.fr/1989CAEN2053.
Pełny tekst źródłaBelmeziti, Ali, i Ali Belmeziti. "Impact potentiel de l'utilisation de l'eau de pluie dans le bâtiment sur les consommations d'eau potable à l'échelle urbaine : le cas de l'agglomération parisienne". Phd thesis, Université Paris-Est, 2012. http://pastel.archives-ouvertes.fr/pastel-00718463.
Pełny tekst źródłaBenzaghou, Salim. "Une approche pour l'utilisation semi-prédictive de l'équation d'état SAFT : application aux hydrocarbures, au dioxyde de carbone, aux alcools, à l'eau et à leurs mélanges". Paris 13, 2001. http://www.theses.fr/2001PA132002.
Pełny tekst źródłaToillon, Julien. "Variabilité génétique et plasticité de l'efficience d'utilisation des ressources (eau et azote) chez les salicaceae cultivées en taillis à courte et à très courte rotation". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0096/document.
Pełny tekst źródłaThis work aimed (1) at characterizing the impact of planting density (PD) and pedoclimatic conditions (sites) on the physiology of poplar and willow dedicated to biomass production, (2) at evaluating the genetic variability of productivity-related traits, water-use efficiency (WUE) and nitrogen-use efficiency (NUE) in a perspective of plant breeding, and (3) at assessing the relationships among these traits. Four experimental plantations were established in northern France. Our results show that PD affects biomass production and WUE depending on sites. Under most favorable growth conditions, trees grown at higher density displayed taller stems, lower stem circumference, and lower WUE, than trees grown at lower density indicating that increased tree density mainly accentuated competition for light. Under less favorable conditions, an increase of PD involved higher WUE and lower stem circumference, likely because of an increased competition for water. Positive links between biomass production and WUE were detected for poplar and willow under environmental conditions where competition for resources was reduced. A large canopy is associated to potentially more important transpiration water losses at plant level. This could be compensated at leaf level through a better stomatal regulation. The absence of antagonism between biomass production, WUE, and NUE suggests the possibility to select genotypes for these three traits independently. Moreover, the Genotype x Site interactions indicated the difficulty to identify good genotypes for a large set of site conditions suggesting that the selection has to be realized depending on the site conditions
Lucero, Daniel William. "Effets de la sécheresse et de l'intéraction entre plantes sur la croissance et l'utilisation de l'eau du trèfle blanc (Trifolium repens) et du Ray-Grass (Lolium perenne) : importance de l'intéraction entre racines". Vandoeuvre-les-Nancy, INPL, 1999. http://www.theses.fr/1999INPL135N.
Pełny tekst źródłaM'BENGUE, ARAME. "Cryopreservation des gros troncs arteriels : etude du controle du processus de cristallisation de l'eau tissulaire et mise au point d'un processus permettant l'utilisation d'allogreffes aortiques cryopreservees chez l'homme". Paris 7, 1999. http://www.theses.fr/1999PA077161.
Pełny tekst źródłaClaustres, Jean-Pierre. "Influence de la pollution atmosphérique sur les échanges gazeux des épicéas : résultats d'une nouvelle méthodologie". Nancy 1, 1992. http://www.theses.fr/1992NAN10058.
Pełny tekst źródłaDaré, William'S. "Comportements des acteurs dans le jeu et dans la réalité : indépendance ou correspondance ? Analyse sociologique de l'utilisation de jeux de rôles en aide à la concertation". Phd thesis, ENGREF (AgroParisTech), 2005. http://tel.archives-ouvertes.fr/tel-00452429.
Pełny tekst źródłaKermarrec, Lénaïg. "Apport des outils de la biologie moléculaire pour l'utilisation des diatomées comme bioindicateurs de la qualité des écosystèmes aquatiques lotiques et pour l'étude de leur taxonomie". Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENA010.
Pełny tekst źródłaThe European Water Framework Directive requires assessing the river quality using chemical and biological indicators among which are diatoms. Indices based on taxonomic composition and relative abundance of diatom taxa are robust. However, thousands of diatom samples are analyzed every year while microscopic identification is difficult due to taxonomic uncertainties, and requires time and expertise. Thus, it is still possible to improve the routine monitoring of water quality. The molecular biology techniques are accurate tools to identify microorganisms and could be used to enhance diatom identification. The objectives of this thesis were therefore to improve our knowledge on the freshwater diatom taxonomy by molecular methods and to progress in the development of a molecular tool in order to identify diatoms in natural samples, thus improving bioindication tools. The taxonomic study of several groups of diatoms was achieved by combining morphological and molecular approaches. Our results showed the capacity of DNA sequences to discriminate diatom taxa and revealed their phylogenetic relationships. The use of DNA sequences showed that the morphological criteria used to identify diatoms do not correspond systematically to their phylogenetic relationships. The use of different markers allowed discrimination at different taxonomic levels. Our results also revealed the importance of combining complementary approaches, morphological and molecular, to improve our understanding of the relationships between different diatom taxa and thus stabilize their taxonomy. As DNA sequences allowed discrimination of diatom taxa, we tested a molecular tool of high throughput sequencing, 454 pyrosequencing, in order to identify the diatom composition of communities. We assembled reference libraries of sequences linked to taxonomic identification and we contributed to the development of bioinformatic tools required to analyze data from pyrosequencing. Finally, we tested these tools to establish taxonomic inventories of diatoms in artificial communities (mixtures of strains) and environmental communities (freshwater biofilm samples). The studies showed the potential of 454 pyrosequencing to accurately analyze diatom communities. The comparison of different nucleic markers revealed that the rbcL marker was the most suitable to identify diatoms using pyrosequencing. Indeed, taking into account reference libraries, reproducibility and bias of the method, and the resolving power of marker, the use of rbcL allowed the best estimation of the diatom composition in complex samples. Improvements will be necessary to use molecular tools in order to assess water quality using diatoms. However our studies lead the way for future experiments in order to achieve a monitoring of water quality based on molecular inventories of diatom taxa
Roupsard, Olivier. "Ecophysiologie et diversité génétique de Faidherbia albida (Del. ) A. Chev. (syn. Acacia albida Del. ), un arbre à usages multiples d'Afrique semi-aride : fonctionnement hydrique et efficience d'utilisation de l'eau d'arbres adultes en parc agroforestier et de juvéniles en conditions semi-contrôlées". Phd thesis, Nancy 1, 1997. http://www.theses.fr/1997NAN10279.
Pełny tekst źródłaDerrien, Morgane. "Validation de l'utilisation des stéroïdes en tant qu'outil de traçage de l'origine des contaminations fécales des eaux de surface". Phd thesis, Université Rennes 1, 2011. http://tel.archives-ouvertes.fr/tel-00674626.
Pełny tekst źródłaGerardin, Théo. "Plasticité et diversité de l’efficience d’utilisation de l’eau chez deux espèces de chêne blanc d’Europe : les chênes pédonculé (Quercus robur L.) et sessile (Quercus petraea (Matt.) Liebl.) : approche descriptive de la dynamique de réponse stomatique aux changements environnementaux". Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0120/document.
Pełny tekst źródłaQuercus robur L. and Quercus petraea (Matt.) Liebl. are two sympatric oak species occupying distinctive ecological niches as well as presenting disparate drought tolerances. Available litterature reports the existence of stable inter-specific differences of water use efficiency (WUE) between the two species, Q. petraea displaying higher values than Q. robur. Water use efficiency can be studied at several integration scales both spatially and temporally. Based on instantaneous foliar gaz exchange, the intrinsic water use efficiency can be determined (Wi). On the other hand, water use can be characterised by measurements of the carbon isotopic composition of plant tissues (13C) or by estimation of the whole plant transpiration efficiency (TE), thus allowing a time-integrated estimate of water use. The characterisation of WUE through these different estimators allowed us to put in evidence in oak seedlings grown under controlled conditions a higher transpiration efficiency in Q. robur even though no differences were observed between the two species regarding instantaneous measurements (Wi). TE variations were mainly linked to the variations of the biomass production by the plants while Wi variations were essentially associated to the stomatal conductance. Both intra and inter specific variations of the dynamics of stomatal response to step changes of environmental factors (light, CO2, VPD) could not be clearly linked to the variations of the different WUE estimates nor their respective components. Nevertheless, drought conditions impacted the stomatal dynamics in both species towards faster stomatal responses, especially for stomatal closing. Furthermore, the main observed differences between species were linked to biomass production. Both species displayed different carbon allocation strategies, especially regarding the root compartment. Thus, Q. petraea produced a significantly more ramified and thinner root system than Q. robur. Such behaviour was accentuated under drought stress, under which Q. robur was more sensitive than Q. petraea in term of biomass production. The complexity of the relationships between water use efficiency and all of these morphological and physiological traits as well as the possible drought tolerance implications in both oak species are discussed in this PhD thesis
Fichot, Régis. "Variabilité structurale et fonctionnelle du xylème et plasticité en réponse à la sécheresse chez le peuplier". Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00579446.
Pełny tekst źródłaMartineau, Elsa. "Rôle joué par le potassium dans la réponse au déficit hydrique du maïs (Zea mays L.) : des mécanismes physiologiques au fonctionnement intégré du peuplement". Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0286/document.
Pełny tekst źródłaPotassium (K) is a major nutrient known to help plants resist drought. In the context of climate change,quantifying the role of K on maize physiological acclimation to reduced precipitations is essential to betterpredict future productivity. Maize (Zea mays L.) plants grown under controlled or field conditions weresubmitted to different K and water levels. Plant growth (shoot and root biomass, grain yield) as well as plantwater status (transpiration, stomatal conductance, water potential) and ecophysiological mechanisms of Carbonmetabolism (photosynthesis, sugar transport) were studied. Regardless of the water regime and experimentalconditions, K nutrition increased growth and whole-plant development and improved grain yield. The effect ofwater stress on stomatal regulation was not straightforward and depended on the level of K fertilization. Theeffects of water or K deficit tend to decrease photosynthesis. Drought or K nutrition affected more leafphotosynthesis in old than in young leaves, and sugar transport did not seem to be a growth limiting factor. Ourresults demonstrated a strong effect of K on biomass production and a higher water use efficiency with less of animpact on leaf-level physiology. This better water use was mainly the consequence of the positive effect of leafarea on yield, and not due to a reduce water use
Wortemann, Rémi. "Etude de la variabilité génétique et de la plasticité phénotypique de la vulnérabilité à la cavitation chez Fagus sylvatica L". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00720995.
Pełny tekst źródłaLetourneux, François. "Efficience et normativité : examen de la légitimité de l'utilisation de la notion d’efficience économique pour l'évaluation de politiques publiques". Thèse, 2015. http://hdl.handle.net/1866/16198.
Pełny tekst źródłaThis text aims to show that efficiency, as used by economists in the context of public policy recommendations, always implies the acceptance of certain moral criterions. I will aim to show that economical recommendations concerning public policy have been identified to utilitarianism in the past. Many economists have then tried to separate their science from debates concerning morals in the XXth century. This separation has had as one of its results the creation of the concept of Pareto efficiency, which has seen wide usage in welfare economics. However, this particular use of efficiency supposes that it is both morally desirable to seek to improve welfare of individuals and that this welfare can be evaluated in terms of preference satisfaction. Both of these affirmations constitute ethical and moral judgements that cannot be made within the sole scope of scientific claims. Efficiency can rather be used in a non-morally controversial way only if the underlying moral considerations are properly identified. A purely scientific use of efficiency needs to take for granted the normative elements implied in measures of efficiency. The determination of the relevance of various social objectives and the relative importance of each of these objectives remains moral questions that cannot be addressed by economics as such.