44 research outputs found

    Photosynthetic traits of freshwater lichens are consistent with the submersion conditions of their habitat

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    In this study, we compared the photosynthetic performance of epilithic freshwater lichens on siliceous stream rock submerged for: more than 9 (hyper-), 6–9 (meso-) or 3–6 months (sub-hydrophilic lichens). In the dry state, neither variable fluorescence nor respiration activity could be detected. In the wet state, rates of dark respiration (O2 uptake and CO2 production for immerged and in-air samples) were in the lower range of that reported for non-aquatic lichens. With 200 (under water) or 500 mmol.mx2.sx1 photosyntheticallly active photon flux density (PPFD) (aerial), photosynthesis was positive but rates were lower than that published for non-aquatic species. Under intense PPFD (2000 mmol.mx2.sx1, aerial), photo- synthesis increased in sub- but became negative in hyper-hydrophilic species. After hydration, dry samples increased photosystem II (PSII) efficiency, which reached near steady state in <6–7 min. Hyper-hydrophilic lichen took longer than sub-hydrophilic species. A long period of desiccation (4 months) had a negative effect on subsequent PSII photochemistry of hyper- but not of sub-hydrophilic hydrated lichens. When thalli were allowed to dehydrate, all types of lichens lost PSII activity after about 15–20 min. Deactivation was faster in the hyper- than in the sub-hydrophilic species. The metabolic traits presented here are thus consistent with the ecological amplitude of the freshwater lichens studied

    Hydraulic conductivity and contribution of aquaporins to water uptake in roots of four sunflower genotypes

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    This article evaluates the potential of intraspecific variation for whole-root hydraulic properties in sunflower. We investigated genotypic differences related to root water transport in four genotypes selected because of their differing water use efficiency (JAC doi: 10.1111/jac.12079. 2014). We used a pressure-flux approach to characterize hydraulic conductance (L 0 ) which reflects the overall water uptake capacity of the roots and hydraulic conductivity (Lp r ) which represents the root intrinsic water permeability on an area basis. The contribution of aquaporins (AQPs) to water uptake was explored using mercuric chloride (HgCl2), a general AQP blocker. There were considerable variations in root morphology between genotypes. Mean values of L 0 and Lp r showed significant variation (above 60% in both cases) between recombinant inbred lines in control plants. Pressure-induced sap flow was strongly inhibited by HgCl2 treatment in all genotypes (more than 50%) and contribution of AQPs to hydraulic conductivity varied between genotypes. Treated root systems displayed markedly different L 0 values between genotypes whereas Lp r values were similar. Our analysis points to marked differences between genotypes in the intrinsic aquaporin-dependent path (Lp r in control plants) but not in the intrinsic AQP-independent paths (Lp r in HgCl2 treated plants). Overall, root anatomy was a major determinant of water transport properties of the whole organ and can compensate for a low AQP contribution. Hydraulic properties of root tissues and organs might have to be taken into account for plant breeding since they appear to play a key role in sunflower water balance and water use efficiency

    QTL analysis of yield-related traits in sunflower under different water treatments

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    A set of sunflower recombinant inbred lines (RILs) was used to study agronomical traits under greenhouse and field conditions each with two water treatments and three replications. The difference among RILs was significant for all the traits studied in all conditions; and water treatment × RILs interaction was also observed for most of the traits in both field and greenhouse conditions. Because of the low rate of drought stress, this part of field data are not informative. Several quantitative trait loci (QTLs) were identified for yield‐related traits with the percentage of phenotypic variance explained by QTLs (R 2) ranging from 4% to 40%. Several QTLs for grain yield per plant (GYP) under four water treatments were identified on different linkage groups, among which two were specific to a single treatment (GYPN.4.1 , GYPI.7.1 ). Three QTLs for GYP were overlapped with several QTLs for drought‐adaptative traits detected in our previous study (Poormohammad Kiani et al. 2007b). The whole results do highlight interesting genomic regions for marker‐based breeding programmes for drought tolerance in sunflower

    Analysis of durum wheat proteome changes under marine and fungal biostimulant treatments using large-scale quantitative proteomics: A useful dataset of durum wheat proteins

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    Durum wheat requires high nitrogen inputs to obtain the high protein concentration necessary to satisfy pasta and semolina quality criteria. Optimizing plant nitrogen use efficiency is therefore of major importance for wheat grain quality. Here, we studied the impact on grain yield, protein concentration, and for the first time on protein composition of a marine (DPI4913) and a fungal (AF086) biostimulants applied to plant leaves. A large-scale quantitative proteomics analysis of wheat flour samples led to a dataset of 1471 identified proteins. Quantitative analysis of 1391 proteins revealed 26 and 38 proteins with a significantly varying abundance after DPI4913 and AF086 treatment, respectively, with 14 proteins in common. Major effects affected proteins involved in grain technological properties like grain hardness, in storage functions with the gluten protein gamma-gliadin, in regulation processes with transcription regulator proteins, and in stress responses with biotic and abiotic stress defense proteins. The involvement of biostimulants in the abiotic stress response was further suggested by an increase in water-use efficiency for both DPI4913 (15.4%) and AF086 (9.9%) treatments. Overall, our work performed in controlled conditions showed that DPI4913 and AF086 treatments promoted grain yield while maintaining protein concentration, and positively affected protein composition for grain quality. Data are available via ProteomeXchange with identifier PXD012469

    A Gene-Phenotype Network Based on Genetic Variability for Drought Responses Reveals Key Physiological Processes in Controlled and Natural Environments

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    Identifying the connections between molecular and physiological processes underlying the diversity of drought stress responses in plants is key for basic and applied science. Drought stress response involves a large number of molecular pathways and subsequent physiological processes. Therefore, it constitutes an archetypical systems biology model. We first inferred a gene-phenotype network exploiting differences in drought responses of eight sunflower (Helianthus annuus) genotypes to two drought stress scenarios. Large transcriptomic data were obtained with the sunflower Affymetrix microarray, comprising 32423 probesets, and were associated to nine morpho-physiological traits (integrated transpired water, leaf transpiration rate, osmotic potential, relative water content, leaf mass per area, carbon isotope discrimination, plant height, number of leaves and collar diameter) using sPLS regression. Overall, we could associate the expression patterns of 1263 probesets to six phenotypic traits and identify if correlations were due to treatment, genotype and/or their interaction. We also identified genes whose expression is affected at moderate and/or intense drought stress together with genes whose expression variation could explain phenotypic and drought tolerance variability among our genetic material. We then used the network model to study phenotypic changes in less tractable agronomical conditions, i.e. sunflower hybrids subjected to different watering regimes in field trials. Mapping this new dataset in the gene-phenotype network allowed us to identify genes whose expression was robustly affected by water deprivation in both controlled and field conditions. The enrichment in genes correlated to relative water content and osmotic potential provides evidence of the importance of these traits in agronomical conditions

    Virtualia 2016. La réalité virtuelle au service de la recherche: Actes du séminaire organisé par le CIREVE à Caen (19 octobre 2016),

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    International audienceLe sĂ©minaire Virtualia est nĂ© en 2006 en mĂȘme temps que le Centre Interdisciplinaire de RĂ©alitĂ© Virtuelle (CIREVE) de l’UniversitĂ© de Caen Normandie. Son objectif est de permettre aux Ă©quipes associĂ©es au CIREVE d’exposer leurs mĂ©thodologies et les rĂ©sultats de leurs travaux dans le domaine de la RĂ©alitĂ© Virtuelle, tout en s’ouvrant Ă  des communications extĂ©rieures. Il a connu quatre Ă©ditions de 2006 Ă  2009.2016 fut l’occasion de relancer VIRTUALIA et de concrĂ©tiser le partenariat avec les UniversitĂ©s de Rouen et du Havre dans le cadre de la COMUE. Une Structure FĂ©dĂ©rative de Recherche « CIREVE » est en effet en cours de labellisation au sein de Normandie UniversitĂ©. 2016 est Ă©galement une annĂ©e importante car elle marque Ă  la fois le dixiĂšme anniversaire du CIREVE et la finalisation d’une plate-forme de rĂ©alitĂ© virtuelle normande, unique en son genre sur le territoire français. Elle est composĂ©e d’une salle immersive quatre faces de 45 m2, Ă©quipĂ©e d’un tapis roulant particuliĂšrement adaptĂ© pour l’analyse de la marche en temps rĂ©el (GRAIL de Motek Medical). Les calculateurs de cette salle immersive sont mutualisĂ©s avec un amphithĂ©Ăątre attenant de 150 places, de maniĂšre que les expĂ©rimentations effectuĂ©es avec un sujet unique dans la salle immersive puissent ĂȘtre suivies par un auditoire nombreux (besoins de formation notamment). Les Ă©quipes utilisent le matĂ©riel au fur et Ă  mesure des dĂ©veloppements informatiques et de nouveaux protocoles d’expĂ©rimentation germent dans l’esprit des chercheurs qui voient dans la rĂ©alitĂ© virtuelle des possibilitĂ©s de tests jamais atteintes.Une centaine de chercheurs utilise rĂ©guliĂšrement le plateau technique CIREVE, dans des visĂ©es de recherche qui leur sont propres. Il est toutefois apparu qu’un certain nombre de problĂ©matiques concernaient toutes les disciplines et qu’une partie de la rĂ©flexion sur les mondes virtuels pouvait ĂȘtre mutualisĂ©e. Le sĂ©minaire VIRTUALIA permet d’offrir un espace de rencontre Ă  ces chercheurs, issus d’horizons diffĂ©rents, pour discuter de l’utilisation de l’outil d’un point de vue Ă©pistĂ©mologique. Il est par exemple capital de s’interroger sur la notion de prĂ©sence. Le sujet se comporte-il de la mĂȘme façon dans l’environnement virtuel et dans le monde rĂ©el ? Les chemins de circulation choisis dans le modĂšle virtuel sont-ils les mĂȘmes que ceux qui seraient empruntĂ©s en rĂ©alitĂ© ? Les conclusions Ă©tablies dans le modĂšle virtuel sont-elles directement transposables Ă  la rĂ©alitĂ© ? Un des enjeux du travail est d’évaluer la pertinence subjective des modĂšles virtuels, ce qui est capital avant de gĂ©nĂ©raliser leur utilisation dans des actions de formation par exemple. L’utilisation d’une technologie n’est jamais complĂštement neutre. Dans le cadre des mondes virtuels, l’interaction de l’homme avec le monde de synthĂšse n’est possible qu’au travers de logiciels et d’interfaces matĂ©rielles. Il faut s’assurer que les processus cognitifs soient adĂ©quats avant de s’interroger sur le rĂ©sultat des simulations. Naturellement, le sĂ©minaire permet Ă©galement Ă  chaque discipline d’exposer les rĂ©sultats des derniĂšres recherches rĂ©alisĂ©es grĂące Ă  la rĂ©alitĂ© virtuelle.Les domaines scientifiques concernĂ©s par la rĂ©alitĂ© virtuelle sont multiples : les civilisations et les patrimoines culturels, la mĂ©decine, les neurosciences, la psychologie, les sciences du mouvement et du sport, l’ingĂ©nierie, l’informatique. L’UniversitĂ© de Caen Normandie Ă©tant pluridisciplinaire, le spectre des utilisations est trĂšs large. Elles se rĂ©partissent en trois axes principaux et un axe en Ă©mergence :LA REPRÉSENTATION : la rĂ©alitĂ© virtuelle permet de reprĂ©senter et de visualiser, interactivement et en trois dimensions, des environnements disparus, dĂ©gradĂ©s, inaccessibles, ou des environnements futurs.Domaines concernĂ©s : civilisations, patrimoine, linguistique...L'EXPÉRIMENTATION : en permettant d'interagir en temps rĂ©el avec un monde numĂ©rique 3D, la rĂ©alitĂ© virtuelle offre de nouvelles perspectives d'expĂ©rimentations dans des environnements de plus en plus proches du rĂ©el et en mĂȘme temps parfaitement contrĂŽlables.Domaines concernĂ©s : santĂ©, neuropsychologie, psychologie, activitĂ©s physiques et sportives...LA CREATION ET LE DEVELOPPEMENT D’OUTILS : les informaticiens crĂ©ent et testent des applications concernant les mĂ©thodes de navigation en monde virtuel, de restitution de la rĂ©alitĂ©.Domaine concernĂ© : informatique.LA FORMATION (axe en Ă©mergence) : par la reprĂ©sentation de la connaissance, par les diverses possibilitĂ©s d'expĂ©rimentation, la rĂ©alitĂ© virtuelle est un formidable outil de formation.Domaines concernĂ©s : sciences du langage, mĂ©decine, informatique (serious game, simulation...).Une partie importante de la rĂ©flexion dĂ©veloppĂ©e lors du sĂ©minaire Virtualia 2016 a Ă©tĂ© consacrĂ©e aux enjeux sociĂ©taux liĂ©s Ă  la rĂ©alitĂ© virtuelle : notions de mĂ©moire, d’apprentissage des gestes techniques, d’ĂȘtre humain « augmentĂ© » etc. Les articles publiĂ©s attestent du savoir-faire, bien rĂ©el cette fois, que le CIREVE a acquis en termes de crĂ©ation de mondes virtuels pour reprĂ©senter, expĂ©rimenter et former. La publication des actes du sĂ©minaire Virtualia vise Ă  mettre en lumiĂšre des recherches particuliĂšrement innovantes qui s’effectuent dans un cadre technologique exceptionnel.- S. Madeleine, Virtualia 2016. Introduction (et direction de l'Ă©dition)- J. Grieu, F. Lecroq, Th. Galinho, H. Boukachour, Environnements industriels virtualisĂ©s et processus d’apprentissage- Ph. Brunet, J. Dehut, Images 3D et humanitĂ©s numĂ©riques : modĂ©lisation et restitution du geste thĂ©Ăątral- G. Lecouvey, J. Gonneaud, N. Legrand, G. Rauchs, F. Eustache, B. Desgranges, RĂ©alitĂ© virtuelle et mĂ©moire- N. Benguigui, C. Mandil, M. Mallek, L. Lejeune, R. Thouvarecq, Étude des liens entre perception et action dans des environnements virtuels- E.-G. Dupuy, A. Maneuvrier, E. Vlamynck, S. Besnard, B. Bienvenu, L.-M. Decker, Le syndrome d’Ehlers-Danlos type hypermobile : Ă©volution des stratĂ©gies posturales en rĂ©ponse Ă  un programme de rĂ©Ă©ducation Ă  visĂ©e somesthĂ©sique- C. Weismann-Arcache, RĂ©alitĂ© virtuelle et humain augmentĂ© : subjectivation, dĂ©subjectivation ?- L. Haddouk, RĂ©alitĂ© psychique en visioconsultatio

    Les pleuro-pneumopathies graves à streptocoque b hémolytique du groupe A en réanimation (à propos de 3 cas)

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    MONTPELLIER-BU MĂ©decine UPM (341722108) / SudocPARIS-BIUM (751062103) / SudocMONTPELLIER-BU MĂ©decine (341722104) / SudocSudocFranceF

    Genotypic Variability in Carbon Isotope Discrimination and Water Use Efficiency among Recombinant Inbred Lines of Sunflower (Helianthus annuus L.)

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    To evaluate genotypic variability in carbon isotope discrimination or CID and water use efficiency or WUE, recombinant inbred lines (RILs) population of sunflower (Helianthus annuus L.) was used. Seventy eight sunflower RILs were grown in greenhouse and 100 sunflower RILs were grown under field condition, and measured some morphological and physiological traits including leaf area at flowering (LAf), net CO2 assimilation rate (A) and transpiration per day at flowering (Ef). WUE, called “potential” WUE (WUEp), was calculated as the ratio of assimilation potential (Ap) to transpiration per day at flowering (Ef) where Ap was derived from the multiplication of A with LAf. The CID was significantly varied among RILs and there was significant negative genetic correlation between CID and WUEp. Heritability of the CID was higher rather than the WUEp which reflected wide genetic variability of CID. The genetic correlation between CID and WUEp and the wide genotypic variability of CID indicated that CID can be proposed as an indicator to determine WUE in sunflower and open a way in understanding the genetic diversity of the RILs which could be used as a basic consideration before applying selection program in sunflower breeding
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