Dissertations / Theses on the topic 'Arbres – Racines (botanique) – Croissance'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Arbres – Racines (botanique) – Croissance.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Atger, Claire. "Essai sur l'architecture racinaire des arbres." Montpellier 2, 1992. http://www.theses.fr/1992MON20100.
Mula, Rachmat. "Modélisation tri-dimensionnelle de la croissance du système racinaire des plantes en milieu hétérogène avec un automate voxellaire : concepts de modélisation et application à des arbres en agroforesterie." Montpellier, ENSA, 2005. http://www.theses.fr/2005ENSA0017.
Dynamic models of root systems should link the pattern of carbon allocation to different parts of the root system and the efficiency of belowground resources capture. Such a model could predict the dynamic growth of root systems in 3D heterogeneous soils. We present such a ‘parsimonious’ model with only six parameters, based on the voxel automata approach. Evidence for the need of such a model was provided by a field study of the spatial root distributions of two tree species, hybrid walnut trees (Juglans nigra x regia cv NG23) and hybrid poplars (Populus euramericana cv I214) cultivated with or without the competition with winter intercrops in southern France. Tree root distributions in the agroforestry plots were much deeper than those observed in the forestry plots, and/or extended laterally beneath the crop zone. More evidence of root plasticity was provided by pot experiments with heterogeneous substrates, or by enriching a small patch in water and/or nitrogen inside the container. The voxel automaton simulates both fine and coarse root growth, and automatically generates its topology. Both the control of ‘genetic’ and environmental factors are incorporated in the root growth process. Container experiments and a split-root experiment were used to parameterise the model for hybrid walnut trees (Juglans hindsii x regia) and wild cherry trees (Prunus avium L. ). The estimated parameter values for walnut and wild cherry trees allow the voxel automata model to be used to predict root patterns of both tree species in various heterogeneous soil experiments. For this purpose, an integration of the root model into a model of tree growth is necessary
Berthier, Stéphane. "Effets des sollicitations aérodynamiques sur la croissance et le développement du pin maritime (pinus pinaster Ait. ) : influence sur la morphogenèse aérienne et racinaire, et sur la formation du bois de cœur." Bordeaux 1, 2001. http://www.theses.fr/2001BOR12443.
O'Connor, Claire. "Caractérisation du partage des ressources en eau et en azote entre les arbres et les cultures au sein de jeunes peuplements agroforestiers." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR013.
Alley-cropping systems (AC) offer several ecosystem services such as biodiversity preservation, carbon sequestration, soil erosion reduction and improving water quality. However, the introduction of trees creates a transition zone between the row and crop alley where the species compete for resources such as space, nutrients, water and light. This competition may induce a decrease of the crop yield. Other studies showed that a root complementarity was established between trees and crops, limiting the competition for water and nutrients. The initialization of deep tree root growth remains poorly understood, even though it is a crucial phase for the well management of agroforestry plots. The objective of this thesis was to characterize the sharing of water and nitrogen during the tree establishment in agricultural plots. The tree fine roots abundance was measured along a chronosequence of seventeen AC ranging from 3 to 12 years old. The water and nitrogen partitioning between trees and crop was monitored on a 4-year-old AC. Tea bags were buried to assess the decomposition of soil organic matter at 30, 50 and 100 cm depth. Several soil samples were taken during these experiments, the main parameters analyzed were water content, nitrogen and organic carbon content and mineral nitrogen content. The chronosequence evidenced that tree fine roots first colonized the topsoil in rows at a young age, but after 5 years of intercropping, they grew mainly vertically in rows before laterally exploring deep soil layers. The 3.5-year-old trees did not impact the water and nitrogen uptake of the crop, but a beginning of competition was detected for the fast-growing trees. Indeed, the soil water content decreased as the trees getting older, especially in topsoil and near the row, contributing to a best use of deep-water resources. Similarly, an increase in soil organic matter was observed in the 10-12-year-old stands in topsoil and within the row, attesting the capacity of AC to store carbon but this process is slow. Finally, the tree fine roots modified the nitrogen dynamics by promoting ammonification. The changes occurring during the conversion from a cropland system to AC are gradual, after 4 years of establishment, trees still had faintly effects on soil resources. Continued monitoring of the AC initialization will allow us to determine if a strong competition for water and nitrogen between the trees and the crop appears, from what age and at what depth
Dupuy, Lionel. "Modélisation de l'ancrage racinaire des arbres forestiers." Bordeaux 1, 2003. http://www.theses.fr/2003BOR12788.
Willaume, Magali. "Influences de diverses opérations de taille et de la croissance rythmique sur le développement racinaire de jeunes chênes blancs (Quercus pubescens)." Avignon, 2005. http://www.theses.fr/2005AVIG0316.
To better understand influence of pruning on roots, the pattern of development of the root system of Quercus pubescens was explored in relation to shoot periodical development and various contrasted defoliation treatments (ablations of mature leaves, cotyledons or young developing leaves). Oak seedlings were grown in rhizotrons for dynamic measurements of root morphological responses, or in pots to compare root growth with dynamics of carbohydrate content in different parts of the root system, and auxin content in apical segments. On control seedlings, we noticed during expansion of the leaves of the second flush a transient decrease in taproot elongation, a concomitant decrease in taproot apical diameter and a stronger decrease in lateral root elongation, showing that root growth in young oak trees is actually sensitive to rhythmic growth. Soluble sugar in apical segments was also reduced during second flush expansion, and increased again after the end of aerial growth. Branching was relatively constant after the end of the first flush development. Starch content in cotyledons decreased regularly. Ablation of source organs (mature leaves or cotyledons) amplified the decrease of root growth concomitant with leaf expansion and caused a large decrease in branching density. A large proportion of lateral roots exhibited delayed emergence. Development of primordia was more affected than initiation. When both cotyledons and mature leaves had been removed, growth decrease was enhanced and density of primordia reduced. Soluble sugar content in apices decreased drastically and starch storage in root basal segment was totally emptied 5 days after defoliation, showing a strong shortage in carbohydrates. Soluble sugar content recovered after the end of aerial growth, suggesting a dense recirculation of sugar in plant. No supplementary recourse to starch content in cotyledons was noticeable. In contrast, continuous ablation of sink organs (young leaves) had no significant effect on the root development pattern and maintained at first elongation and branching characteristics, before gradual and slight decrease in lateral root. Apical sugar content was also maintained and starch storage in basal root segments improved. As important auxin sources have been removed in this treatment, a limitation in auxin could have occurred. However, even if auxin apical contents tended to be reduced, no treatment had a significant effect on auxin content. The parallel between pattern of apical sugar content and root growth pattern, and the strong correlations between hexose content in the root apex and its growth rate support the hypothesis of a major control of growth through carbohydrate availability in the root response to periodic growth and defoliation treatments
Plante, Pierre-Manuel. "Distribution racinaire de trois espèces d'arbres implantées en haies brise-vent selon deux types de sol contrastants." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/29287/29287.pdf.
Buée, Marc. "Mise en évidence d'un facteur racinaire impliqué dans la croissance des champignons mycorhiciens à arbuscules." Toulouse 3, 2000. http://www.theses.fr/2000TOU30194.
Sanoja, Elio. "Essai d'application de l'architecture végétale à la systématique : L'exemple de la famille des "Vochysiaceae"." Montpellier 2, 1992. http://www.theses.fr/1992MON20291.
Voisin, Anne-Sophie. "Etude du fonctionnement des racines nodulées du pois (Pisum sativum L. ) en relation avec la disponibilité en nitrates du sol, les flux de carbone au sein de la plante et la phénologie : croissance des racines nodulées et activité fixatrice des nodosités." Dijon, 2002. http://www.theses.fr/2002DIJOS005.
Garcia-Villanueva, Eduardo. "Développement conjoint des systèmes aérien et racinaire chez deux génotypes de pommier (Malus X domestica Borkh)." École nationale supérieure agronomique (Montpellier), 2004. http://www.theses.fr/2004ENSA0020.
Calvaruso, Christophe. "Quantification de l'effet des racines d'arbres et des microorganismes associés sur l'altération des minéraux de sols forestiers : observations en forêt et expérimentations." Nancy 1, 2006. http://docnum.univ-lorraine.fr/public/SCD_T_2006_0129_CALVARUSO.pdf.
The impact of the mineral weathering process on tree nutrition in acidic forest soils is well known. However, the quantitative effect of different biological factors on this process remains to be clarified. In this context, the aim of the present work was to quantify the impact of the rhizosphere of forest trees (roots and associated microorganisms) on the weathering of soil minerals. In forest, we observed an increase of the weathering of minerals (dissolution and transformation) in the rhizosphere of trees, suggesting an important impact of the tree rhizosphere on the dynamics of minerals as well as on soil evolution. We characterized in vitro the weathering potential of microorganisms which were isolated in forest from bulk soil and ectomycorrhizas. We showed that the ectomycorrhizal symbiosis significantly structures the functional diversity of culturable bacterial communities and selects strains potentially beneficial to tree nutrition. We developed a column experiment to quantify the respective impact of plant, bacteria and fungi on the weathering process. We demonstrated that tree roots and bacteria significantly increase Mg, K, Fe, Cs, Ni mobilisation via the weathering of a reference mineral. This process is altered in the presence of toxic elements such as uranium. Considering the whole of our results, we can propose the following hypothesis: in forest soils, the nutrient bioavailability determines the mineral weathering due to its impact on the root and microorganism activity. This suggests an important plasticity of forest ecosystems towards nutrition, which could partly explain the sustainability of these ecosystems
Meredieu, Céline. "Croissance et branchaison du pin laricio (Pinus nigra Arnold ssp laricio (Poiret) Maire) : élaboration et évaluation d'un système de modèles pour la prévision de caractéristiques des arbres et du bois." Lyon 1, 1998. http://www.theses.fr/1998LYO10242.
Dahlan, Zulkifli. "Croissance et développement du système souterrain de quelques bambous tropicaux et tempérés : observations et expérimentation." Montpellier 2, 1991. http://www.theses.fr/1991MON20194.
Poulain, Jérôme Matthias. "Étude du rôle de gènes contrôlant le cycle cellulaire au cours du développement racinaire de Cichorium intybus L. : isoolement et caractérisation d'une cycline mitotique de type B de chicorée." Lille 1, 2003. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2003/50376-2003-199-200.pdf.
Thongo, M'Bou Armel. "Etude du système racinaire de l’Eucalyptus en plantation tropicale : analyse architecturale, croissance et respiration." Thesis, Nancy 1, 2008. http://www.theses.fr/2008NAN10039/document.
The aim of this study was to study the development of the root system of the 1-41 clone of Eucalyptus in Congo. Root architecture was studied in an age serie stands. A root typology was proposed with five classes of roots and three main functions: soil exploration with both lateral and vertical roots, soil exploitation with a network of fine roots and re exploitation of the soil zone by late emitted roots. All of these root types appeared at all the studied stages because of reiterations that allow the root system to explore a large soil volume. The results of root respiration study were used to parameterize a root respiration model with root respiration partitioned between a growth component, a maintenance component and a nutrient absorption component. The model was then applied using field data of fine root biomass and nitrogen content of whole tree biomass to estimate fine root respiration of a Eucalyptus stand. The simulated value fits reasonably well with independent estimates of root respiration in this site. Estimations of fine root production and turnover were highly variable depending of the methods used. The more realistic one predicts a turnover of 4 year-1, i.e. a high recycling of carbon and nutrient by belowground litter. Results of this study offer promising perspective for developing an architectural model of root development and its use to establish carbon, water and nutrient budget in Congolese Eucalypt plantation
Lucas, Mikaël. "Flux d'auxine et ramification racinaire chez Arabidopsis thaliana : vers une racine virtuelle." Montpellier 2, 2008. http://www.theses.fr/2008MON20047.
Plants depend on their roots for anchorage and nutrition. The architecture of the root system a key factor for these two functions. In the model plant Arabidopsis thaliana, root branching is the composotion of events of initiation and emergence of new lateral roots. While individuals events of initiation and emergence are well described at the cellular and molecular level in Arabidopsis and are known to be linked with the plant hormone auxin, little is known about the precise mechanisms regulating those events. Using an approach combining biology, mathematical analyses and computer modelling, this thesis project aimed to elucidate those mechanisms in Arabidopis, and to propose an integrated view of root branching
Fakih, Mahmoud. "Modélisation numérique discrète de la croissance racinaire dans un sol : relation force-forme." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT323/document.
Plant roots play an important role in the growth and development of plants, and it is well known that the mechanical interactions between a growing root and the surrounding soil can have a major impact on root growth and consequently on plant biomass production. These mechanical interactions are one of numerous factors that explain the variability of root architecture, including genetics, environment and developmental instability. But this factor has often been under-estimated. I hypothesize that the heterogeneous structure of soil at the particle scale, demonstrated by the broad distribution of forces, can significantly influence root growth trajectories. This thesis aims at determining how grains in granular soils are reorganized under the action of growing roots, and in return how the resulting forces acting on root tips modify their development, including the kinematics of their trajectories, in order to develop a general biophysical law of root-soil mechanical interactions. I developed a 2D numerical model of root growth in a granular medium using a Discrete Element Model (DEM). The model is able to compute grain-grain and root-grain contact forces within a granular medium. The root system is modelled using chains of connected spheroline elements. The orientation of root growth at every growth step is determined by the dynamics of the whole root under the action of its internal elastic forces and reaction forces exerted by the grains, which are the mechanical interactions that control numerical growth in the model.Parametric studies were carried out in order to (i) estimate the influence of granular structure (grain diameter distribution, cohesion, volume fraction) and root mechanical properties (root bending stiffness) on the axial force signal acting on the root tip, and on the root trajectories and (ii) define general physical laws that can be used further to analyze experimental data. The distribution curves of computed root tip-grain forces normalized by the mean force during a given period of growth were characterized by a decreasing power law for forces below the mean force, and an exponential fall-off for forces above the mean force, thus reflecting the broad distribution of forces inside the granular material. An analysis of the standard deviation of the local deformations of root trajectories resulted in two different regimes with regard root stiffness. In the first regime, soil controlled the root deformation and in the second, the root trajectory was straighter and displaced more significantly the surrounding grains during growth
Laghdir, Aziz. "Modélisation de la fissuration en bout de grumes liée aux contraintes de croissance : application aux eucalyptus." Montpellier 2, 2000. http://www.theses.fr/2000MON20079.
Ehlert, Christina. "Importance de la conductivité hydraulique racinaire pour le contrôle de la croissance foliaire chez le maïs (Zea mays L. )." Montpellier SupAgro, 2008. http://www.theses.fr/2008NSAM0007.
In maize, leaf growth reduction by increased evaporative demand appeared to depend on either plant water status (Hsiao et al. , 1998) and/or soil-to-root hydraulic conductivity (Bouchabke et al. , 2006). Difficulties in controlling soil-to-root characteristics has hindered to evaluate their role in plant responses to evaporative demand. The discovery of aquaporins and the recent insights into their gating properties offered the possibility to assess the role of root water uptake characteristics, in particular hydraulic conductivity of the roots (Lpr) for leaf growth rate and water flow in intact plants. In this thesis, Lpr reductions were induced by a range of treatments which affected Lpr by aquaporin down-regulation such as acid root loading, anoxia and hydrogen peroxide. These treatments were combined with a range of evaporative demands, and short term responses of leaf elongation rate, water flow and water potentials were followed. It was concluded that, firstly, aquaporins controlled an important part of the water transport across maize roots with primary impacts on water potential gradient rather than on water flow. Secondly, the Lpr controlled the responsiveness of leaf elongation rate to fluctuating evaporative demand. Thirdly, turgor pressure of growing cells responded like leaf elongation rate to combined changes in root hydraulic conductivity and plant transpiration rate, and could therefore explain the interactive effects of water availability and evaporative demand on leaf growth. A modelling approach was developed to further support this conclusion. Lastly, on a short term time scale, anoxia inhibited maize leaf growth following the same hydraulic signalling cascade as induced by pharmacological treatments targeting root aquaporin inactivation. We conclude that environmental conditions affecting Lpr, such as anoxia, class this variable as a putative strong determinant for whole plant adaptation to environmental stresses
Mohamed, Awaz. "Relations entre phénologie de la croissance souterraine et aérienne de noyers hybrides en systèmes agroforestiers tempérés." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT154/document.
The study of phenology is primordial to understand tree response to climate change. Although many studies have examined shoot phenology, the difficulties in observing root system growth have resulted in a poor understanding of root phenology. As root system dynamics are considered as playing a major role in carbon cycling and sequestration, it is necessary to overcome methodological difficulties, so that root demography can be studied in the field and over several years. Our first objective was therefore to develop and evaluate methods for studying root system growth in the field. Studying mature hybrid walnut (Juglans L.), growing in agroforests, We showed that smartphone scanners are the best adapted tool for acquiring high quality images of tree roots growing in field rhizotrons. However, time-lapse cameras were good alternatives when a fully automated method was required (up to 4 months autonomy). Our second objective was to determine the main drivers of walnut hybrid root growth in field conditions. In particular, (i) We hypothesized that shoot and root phenologies were asynchronous, (ii) We evaluated the effect of environmental factors on root growth along a latitudinal gradient comprising three climates (Mediterranean, oceanic and continental) and (iii) We determined how phenology and environmental factors influenced root dynamics depending on root morphology and topology. Results show that flushes of fine root growth are not synchronized with budburst and leaf expansion, but are synchronized with stem and coarse root radial growth. Soil temperature was on the whole the main driver of root growth, and to a lesser extent, soil humidity, but which had contrasting effects on root growth. Root topological order had a major influence on root response to environmental variables, reflected in root elongation, production and longevity. Results will be highly useful not only for a better understanding of the role that root systems play in the carbon cycle, but also for tree ecophysiological models. Future studies should expand the knowledge gained here into a global understanding of the drivers of tree root initiation, growth and longevity, through the creation of databases and the use of meta-analyses
Villeneuve, Chantal. "Influence de la présence de racines adventives et du continu en eau du substrat sur l'échange gazeux, la croissance et l'allocation glucidique chez les semis d'épinette noire (Picea mariana (Mill.) B.S.P.) /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1997. http://theses.uqac.ca.
Trujillo, Hernández José Abraham. "Etude de suppresseurs de la glutarédoxine GRXS17 dans la croissance racinaire et la thermotolérance." Thesis, Perpignan, 2019. http://www.theses.fr/2019PERP0017/document.
Auxins are critical key components for the control of root development and response to environmental constraints by its pivotal roles in cell division, elongation, and cell differentiation. The endogenous auxin Indole-3-butyric acid (IBA), although less abundant than the better-known Indole-3-Acetic Acid (IAA), plays important roles during root development especially during the formation of lateral roots and root hairs elongation. It is generally accepted that IBA functions are fully dependent on peroxisomal IBA-to-IAA conversion. While there is a great advance in our knowledge regarding the enzymes involved in the peroxisomal conversion of IBA-to-IAA, little is known about the mechanisms that modulate its functions. During my thesis, I demonstrated that the IBA functions during the induction of lateral roots and root hairs elongation are dependent on glutathione, which is a small redox tripeptide that constitutes one of the most important molecules involved in plant responses to oxidative stresses. Moreover, I demonstrated that the link between glutathione and the auxin IBA is critical for the auxin distribution that takes place in the transition zone of the primary root. The relevance of the control of IBA functions by glutathione might be determinant during abiotic stress conditions such as phosphorus deprivation.Since glutathione is a reducer of thiol reductases glutaredoxins (GRXs), we investigate if some GRXs are involved in root development. We found that ROXY19 and GRXS17 are critical for the primary root growth, and both GRX proteins play different roles during the formation of lateral roots. Based on this root phenotype, a suppressor screen in grxs17 background had been set up in the lab. I developed bioinformatic pipelines to isolate causal mutations from genome resequencing of candidates that are able to restore the primary root growth and/or the normal development of lateral roots primordia. Unfortunately, this approach did not yet allow us to isolate new actors, however it builds foundations for future big advance in understanding how glutaredoxins control the root system.In conclusion, the results showed in my Ph.D. thesis highlight the importance of glutathione and glutaredoxins in the control of the root system plasticity and during abiotic stress conditions, particularly via the modulation of the auxinic IBA pathway
Fournier, Mylaine. "Structure et croissance d'un peuplement d'épinette noire (Picea mariana) issu d'une coupe d'une vingtaine d'années dans la région du Saguenay-Lac-Saint-Jean /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1997. http://theses.uqac.ca.
Fortin, Marie-Noëlle. "Étude descriptive des relations de croissance entre la tige, la racine pivotante et les racines horizontales chez le pin gris (Pinus banksiana) dans la région du Lac Saint-Jean, Québec /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2004. http://theses.uqac.ca.
Silvestre, Jérôme. "Étude des conséquences de l'asphyxie racinaire sur la croissance et le développement du colza d'hiver." Toulouse, INPT, 1992. http://www.theses.fr/1992INPT033A.
Aubin, Normand Kevin. "Influence du contenu en eau du substrat et de la profondeur de plantation sur la formation de racines adventives caulinaires, la croissance et l'allocation glucidique de semis d'épinette noire (Picea mariana (Mill.) B.S.P.) /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1996. http://theses.uqac.ca.
Walsh, Denis. "Gauchissement de la tige et croissance de semis de conifère traités à l'éthylène et soumis à l'anaérobiose racinaire /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1993. http://theses.uqac.ca.
Bogeat-Triboulot, Marie-Béatrice. "Effets du stress osmotique et de la carence en potassium sur la croissance racinaire du pin maritime : étude biomécanique du grandissement cellulaire." Nancy 1, 1996. http://docnum.univ-lorraine.fr/public/SCD_T_1996_0019_TRIBOULOT.pdf.
This work allowed us to improve our knowledge about the control of root growth of maritime pine. This study, which is based on a biophysical analysis of cell expansion, utilised two new microtechnologies: the cell pressure probe and the picolitre osmometer. In unstressed plants, cell turgor pressure was uniform over the entire elongation zone. On the other hand, cell wall rheological properties changed during cell maturation and controlled cell expansion. Three levels of osmotic stress affected root growth differently. A moderate water deficit stimulated root growth by increasing cell wall extensibility, in spite of a small decrease of cell turgor pressure. During the medium water deficit, a reduction of cell turgor pressure was compensated by an increase of cell wall extensibility, root growth rate was not affected. During the highest water deficit, root growth was inhibited by a strong reduction of turgor pressure. The root system responded heterogeneously to a potassium shortage. Tap root growth was not modified by this constraint: neither turgor pressure nor rheological properties were affected. On the other hand, lateral roots growth was strongly inhibited by a reduction of cell wall extensibility. Moreover, in the apex of the tap root, a small reduction in potassium concentration (divided by 2), and also of other inorganic ions, was completely compensated by an increase of soluble sugars and glutamine concentrations. In the apex of lateraI roots, a large reduction in potassium concentration (divided by 8), and of other inorganic ions, was practically not compensated, inducing a reduction of the osmotic pressure in mature tissues
Rouhier, Hervé. "Réponse du châtaignier (Castanea sativa Mill. ) à l'augmentation du CO² atmosphérique : croissance et activité rhizosphérique." Lyon 1, 1994. http://www.theses.fr/1994LYO10140.
Obeid, Saleh. "Influence de la température des racines sur la croissance des jeunes plants de melon (Cucumis melo L. ) : aspects particuliers concernant la nutrition phosphatée." Montpellier 2, 1989. http://www.theses.fr/1989MON20177.
Richter, Felten Judith. "Développement racinaire du peuplier en réponse aux signaux fongiques lors de la mise en place de l'ectomycorhize." Thesis, Nancy 1, 2009. http://www.theses.fr/2009NAN10110/document.
The early phase of the interaction between tree roots and ectomycorrhizal (ECM) fungi is accompanied by a stimulation of lateral root (LR) development. This thesis aims on understanding by which molecular mechanisms the interaction of plant and fungus induces LR stimulation. Therefore the ECM fungus L. bicolor in interaction with one of its mycorrhizal hosts, Populus tremula x Populus alba or with the non-mycorrhizal herbaceous model plant Arabidopsis thaliana was studied. We identified gene networks that regulate LR development during the early signal exchanges between Populus tremula x Populus alba and the ECM fungus Laccaria bicolor. We focussed on auxin transport and signalling pathways, as those are key actors regulating LR development. Experiments with poplar and Arabidopsis transgenic auxin response marker lines revealed that the presence of fungal signalling molecules modified auxin gradients in roots. Using microarray- and quantitative Real-time PCR based transcript profiling of poplar roots we uncovered the accumulation of transcripts of the polar auxin efflux carrier PtaPIN9 as well as of auxin responsive transcription factors. A. thaliana transgenics defective in these targets showed that they are crucial for fungus induced LR stimulation. Finally we identified an involvement of ethylene, jasmonates, brassinosteroids and ROS (Reactive Oxygen Species) signalling during fungal LR induction. These pathways are known to be activated upon stress responses in the plant and to interact with auxin pathways. Together these data show how ECM fungi stimulate LR development in plants by interfering with endogenous auxin-levels, -distribution and -signalling most probably through stress signalling pathways
Lagrange, Hubert. "Identification de signaux racinaires régulant l'accumulation d'hypaphorine et la croissance du champignon ectomycorhizien Pisolithus tinctorius." Nancy 1, 2001. http://www.theses.fr/2001NAN10262.
Chen, Gwennaëlle. "Rôles de polygalacturonases (PG) dans le développement racinaire, chez Arabidopsis thaliana." Thesis, Amiens, 2018. http://www.theses.fr/2018AMIE0022/document.
Plant cell wall structure is modified to control its stiffness or flexibility according to plant’s requirements. The cell wall is a complex structure, composed of cellulose, hemicelluloses and pectins. Pectin modifications during cellular elongation are not very well characterized. In this context, the aim of this project is to study the roles of two polygalacturonases (PG) in the root development on the model plant A. thaliana. PG are homogalacturonans (HG) degradation enzymes, HG being the major pectic component of the primary cell wall. This degradation would lead to a local parietal relaxation, allowing anisotropic growth of the cells. Our results show that the two studied PG, named PG ROOT APICAL MERISTEM (PG RAM) and PG ROOT (PG R), are expressed in complementary areas of the root, either in the root apical meristem (PG RAM) or in the elongated and differenciated root tissues (PG R). Furthermore, the over-expression of PG R results in longer etiolated hypocotyls and increases root density when compared to wild-type, demonstrating its function in root development and in cell elongation. Finally, we demonstrated that expression of these two PG genes is under the control of PLETHORA (PLT) family transcription factors, by differentially ways
Sierra, Julia. "Études des mécanismes de croissance des racines Datura innoxia : application à la culture en bioréacteur avec divers modes de conduite." Compiègne, 2007. http://www.theses.fr/2007COMP1708.
The subject of this thesis work is to study various operating modes for the production of Datura innoxia hairy roots in Erlenmeyer scale and in laboratory bioreactor scale. The aim of this work is to improve the production perfomances by trying to improve the growth kinetics by providing the best operating conditions with a minimum doubling lime and a maximum biomass production. The work in Erlenmeyer scale was focused on the needs of hairy roots concerning species composing the nutriment. While the work in the bioreactor scale was more especially oriented to the optimization and improvement of the operating conditions in which a maximum of biomass can be obtained for a given time. At the light of these studies, it is found that the best "preparing mode" in Erlenmeyer scale is that obtained in vibrated Fembach flat bottom flasks with an adapted culture medium. These flasks provide bigger gas/liquid contact area and good performance with the vibrating system. The lime of doubling at these conditions is only 1. 86 days. A number of operating modes have been studied: batch, atomization, cyclic and nutriment renewal. The doubling lime with the fed-batch mode is found to be 2. 4 days. We also demonstrated that the growth of Datura innoxia hairy roots at the exponential phase can be described by Monod's equation. The best global perfomance at bioreaetor seale is obtained with fed-batch operating mode where the hairy roots are fed regularly during the culture period
Lamontagne, Manuel. "Influence du gauchissement de la tige de l'épinette noire (Picea mariana (mill.) BSP) sur le redressement de la tige et la croissance des plants de plus d'un an /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1993. http://theses.uqac.ca.
Mantelin, Sophie. "Effet stimulateur d'une souche PGPR de Phyllobacterium sur la croissance d'arabidopsis thaliana : Caractérisation de la réponse morphogénétique du système racinaire et impact sur la nutrition azotée." Montpellier 2, 2004. http://www.theses.fr/2004MON20214.
Fantin, Natalie. "Croissance juvénile des arbres mères comparée à celle de jeunes semis d'épinette noire (Picea Mariana (Mill) B.S.P.) issus de graines après un feu sur un même site /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1999. http://theses.uqac.ca.
Martinez, Jacques. "Approche génétique et physiologique de la croissance et du développement à basse température chez quelques "Lycopersicon"." Montpellier 2, 1992. http://www.theses.fr/1992MON20234.
Al-Ghazi, Yves. "Recherche de gènes implqués dans les modifications d'architecture du système racinaire induites par la carence en phosphate chez Arabidopsis thaliana." Montpellier, ENSA, 2003. http://www.theses.fr/2003ENSA0007.
One of the major plant responses to phosphate privation concern the modification of root development. The aim of this work is to precise the molecular basis on this response. In phosphate-limiting conditions, Arabidobsis develops a chronological sequence of numerous morphological root changes including a decrease of primary root growth rate, an increase of secondary root growth rate combined with a reduction of primordia numhers and a decrease of root growth cessation. This adaptive response seems to he under the control of auxin pathway. The design of a DNA array, dedicated to the Arabidopsis transcription factors, allows the measurements of gene expression Icvel of these factors in a time-course according to the described biological model. Data analysis leads to the selection of 19 genes whom the expression profiles are strongly disturbed by the phosphate privation condition. Root morphological analysis of four transcription factor knock-out mutants from the selected genes confirm the involvement of these factors in the root adaptive response to phosphate privation. The gene mutations induce, specifically to each of the mutants, the loss of the adaptive response of primary and secondary roots. Moreover preliminary transcriptome analysis of the se mutants show the implication of various genes to phosphate detïciency and/or to root development. This work leads to the selection of 4 transcription factors which should constitute the first elements of response
Jourdan, Christophe. "Modélisation de l'architecture et du développement du système racinaire du palmier à huile (Elaeis guineensis Jacq. )." Montpellier 2, 1995. http://www.theses.fr/1995MON20208.
Lussier, Jean-Martin. "Comparaison de la croissance de marcottes d'epinette noire adultes à celle d'individus issus de graines après feu /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1991. http://theses.uqac.ca.
Dubé, Marie-Christine. "Effet d'une épidémie de la tordeuse des bourgeons de l'épinette sur la croissance de la tige et le développement racinaire des semis de sapin dans des sapinières boréales /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1999. http://theses.uqac.ca.
Fellahi, Ahmed. "Influence de la température des racines sur la nutrition potassique de la tomate (Lycopersicon esculentum Mill. ) en condition contrôlée : aspect particulier concernant le rôle du rayonnement global." Aix-Marseille 3, 1995. http://www.theses.fr/1995AIX30073.
Heuret, Patrick. "Analyse et modélisation de séquences d'événements botaniques : applications à la compréhension de la régularité d'expression des processus de croissance, de ramification et de floraison." Nancy 1, 2002. http://www.theses.fr/2002NAN10001.
Thaler, Philippe. "Relations entre développement racinaire et développement aérien : modélisation de l'influence de la disponibilité en assimilats carbonés sur l'architecture racinaire d'"Hevea brasiliensis"." Montpellier 2, 1996. http://www.theses.fr/1996MON20258.
Touraine, Bruno. "Régulation de l'absorption racinaire de NO3̄ par les parties aériennes." Montpellier 2, 1992. http://www.theses.fr/1992MON20206.
Vayssières, Alice. "Contrôle de l'auxine dans les modifications du développement racinaire du peuplier en réponse au champignon ectomycorhizien Laccaria bicolor." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0017/document.
Root systems of host trees are known to establish the ectomycorrhizal (ECM) symbiosis with rhizospheric fungi. This mutualistic association leads to modifications of root development that including a stimulation of lateral host roots, and a modification in root growth. The phytohormone auxin (Indole-3-acetic acid, IAA) is known to regulate LRs formation and root growth. Our research focussed on auxin pathways in poplar root in response to L. bicolor. In this study, our data showed that the poplar-Laccaria bicolor interaction leads to the arrest of LRs and adventitious root growth after two weeks of interaction. We also showed that this arrest is not regulated by the Hartig net. Differential auxin responses were analyzed by using an auxin-responsive DR5::GUS marker line and revealed a loss of auxin response in ECM roots. An oligoarray-based transcript profiling of poplar roots in contact with L. bicolor highlights a differential expression of auxin asociated genes in ECM. Measurement of auxin metabolite in ECM and in the free living partners revealed an IAA accumulation, an activation of the IPyA (Indol-3-Pyruvic Acid) dependant IAA biosynthesis pathway in both partners, as well as changes in IAA conjugation pathways in poplar and in IAA degradation pathways in L. bicolor. Our findings illustrate the impact of L. bicolor colonization on root auxin metabolism and response, and also suggest a role of auxin as a signal in the formation of ECM and in the regulation of ECM function. In parallel, PtaPIN9 function analysis in response to L. bicolor has been performed. PtaPIN9 immunolocalization in poplar roots showed similar localization to AtPIN2 in epidermis cells. Transgenic lines having a modification in PtaPIN9 expression, did not formed new LRs in respond to L. bicolor. In ECM roots, the loss of PtaPIN9 signal is observed but modifications of PtaPIN9 expression did not modify the root growth arrest and the Hartig net formation. These results show major changes in auxin associate pathways in poplar root by the symbiotic fungus L. bicolor, during the formation of the mycorrhiza root. Our results offer perspectives on the role of auxin in root development and in the context plants-microbes interactions
Yang, Ming. "Ancrage racinaire des arbres : modélisation et analyses numériques des facteurs clés de la résistance au vent du Pinus pinaster." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0279/document.
Winter storms cause 50% of wood damage by volume to European forests. Tree uprooting isthe most frequent phenomenon during storms ; however the mechanism is not well understood.This thesis aims to better understand the tree uprooting process and to identify both rootstructural features and material properties which have first-order effects on tree anchoragestrength for the case ofPinus pinaster. A Finite Element Model has been developed and allowedsimulating and tracking the sequential root breakage during the course of tree overturning. Anoverall tree anchorage strength is thus defined as the resultant of contribution of root systemarchitecture and material strength (roots, soil). This would allow improving the risk modelswhich currently don’t include any mechanistic relationships to describe tree uprooting. In thesame spirit, we have relied on root architectural data to build a simplified root system patternwith features ofP. pinaster. Importance of different root components has been studied andthe essential role of the taproot and shallow roots demonstrated. This result has confirmednumerous experimental and theoretical studies and for the first time quantified these impacts.Therefore the number of relevant parameters can be reduced to express overall root anchorage.This opens new prospects to simplify the model in order to apply to other species under othersoil conditions and considering different silvicultural practices
Truskina, Jekaterina. "The role of auxin in cell differentiation in meristems." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEN033/document.
Auxin regulates plant growth and development through the transcription factors of the AUXIN RESPONSE FACTOR (ARF) gene family. Most notably in Arabidopsis thaliana ARF5, 6, 7, 8 and 19 activate expression of target genes in response to auxin. These five ARF activators control both variable and overlapping processes during plant development including regulation of growth at the root and the shoot apical meristems, lateral root and axillary shoot formation. Each of the five ARF activators shows unique tissue-specific expression patterns in the root and the shoot associated with their distinct functions. This tissue-specific expression is likely derived from the differences in the control of ARF activator transcription. In this study the upstream regulators of ARF5, 6, 7, 8 and 19 transcription were identified. This was achieved by utilizing a high-throughput yeast one-hybrid (Y1H) method. The transient protoplast assay revealed that each ARF activator is controlled by specific transcriptional regulators and that the majority of these regulators are repressors of ARF transcription in planta. Mutants of the regulatory transcription factors were utilized to additionally investigate the interactions in planta. These mutants display auxin-related developmental phenotypes in the root and the shoot including alternations in growth kinetics, emergence of lateral organs, responses to auxin and altered expression of ARF activators. Furthermore, this study additionally focuses on cross-talk between the auxin and cytokinin signaling pathways and its role in root and shoot development. One of the interactions identified in the Y1H screen is a repression of ARF7 by CRF10, a member of the Cytokinin Response Factors gene family. The importance of this interaction in maintaining architecture of the root apical meristem, in leaf senescence and in the phototropic response to blue light in hypocotyls is studied