EVALUATION DE L'EFFICACITE ET DE LA TOLERANCE DE LA FEXOFENADINE DANS LE TRAITEMENT DE LA RHINITE ALLERGIQUE SAISONNIERE

REIMS-BU Santé (514542104) / SudocSudocFranceF

Which cropping systems to reconcile weed-related biodiversity and crop production in arable crops? An approach with simulation-based indicators

International audienceWeed management must both control weed harmfulness for crop production and promote weed contribution to biodiversity as an essential component of biodiversity in agricultural landscapes. The objective of the present paper was to evaluate a large range of existing cropping systems to determine management rules for reconciling weed-related biodiversity and weed harmfulness, comparing 26 contrasting cropping systems identified via farm surveys in two contrasting French regions, Burgundy and Poitou-Charentes. These systems were simulated, using the weed dynamics model FlorSys which predicts weed flora dynamics over the years, depending on cropping system and pedoclimate. The simulated flora was translated into five weed harmfulness indicators (crop yield loss, harvest contamination, harvesting difficulty, field infestation, additional crop disease due to weeds) and five weed-related biodiversity indicators (weed species richness and equitability, weed-based trophic offer for birds, insects and pollinators). Cropping system performance was assessed with a Principal Component Analysis (PCA) on the 10 weed-impact indicators, followed by a hierarchical clustering analysis. Five contrasting profiles in terms of weed harmfulness and contribution to biodiversity were identified, combining different levels of weed harmfulness and biodiversity. To identify management strategies (i.e., combinations of cultural practices) for reaching these different performance profiles, tree-based regression and classification models (CART) were constructed to explain performance profiles as a function of cropping system descriptors and pedoclimatic variables. Ten management strategies were identified for reaching the five performance profiles. The most interesting performance profile, which minimized all harmfulness indicators (except harvest contamination and harvesting difficulty) and maximized all biodiversity indicators (except species richness), was reached by a single strategy type, consisting of low or no-till systems. Systems with cover crops and little or no mechanical weeding also reconciled most production and biodiversity goals. Multiple management pathways for reaching a given goal present the advantage of letting farmers choose the strategy most compatible with the objectives and constraints of their farm. The present results were obtained with annual weed species only, and taking into account the management of perennial weeds will probably modify the strategies. The same method was also applied to identify strategies for reconciling crop production, biodiversity and reduced herbicide use, though none of the investigated cropping systems was able to reconcile all three objectives, indicating that novel cropping systems must be designed specifically for this objective. (C) 2015 Elsevier B.V. All rights reserved

Biomacromolecules

Lignocellulosic biomass is considered as a sustainable source of energy and chemicals, but its recalcitrance to bioconversion still limits its use. In this paper, a strategy based on two aspects was developed to improve our knowledge on the lignin recalcitrance to enzymatic hydrolysis. First, lignocellulosic films of cellulose nanofibrils (CNFs) with increasing content of lignin (up to 40%) were prepared. Thanks to in situ real time Atomic Force Microscopy (AFM) measurements during the hydrolysis and by comparison with biochemical assays, the use of such films allows to fully assess the importance of the lignin content and of the arrangement between CNFs and lignin on the hydrolysis efficiency. In a second time, contrary to other studies by AFM which only followed a specific structure during enzymatic processes mostly on simple systems (CNFs or cellulose nanocrystals), a quantitative analysis of in-situ time-lapse measurements was developed. It enables to accurately address lignocellulosic biomass recalcitrance mechanisms mediated by lignin at nanoscale. Such analysis could pave the way for the use of a quantitative criteria to visualize in situ deconstruction of complex lignocellulosic substrates. Coupling the use of lignocellulosic films and dynamical AFM quantitative analysis to follow the evolution of the structure at nanoscale might lead to an effective targeting of new promising bioconversion strategies

Résistance du vulpin aux herbicides. Son importance et sa répartition en Côte d'Or

National audienceBlACKGRASS lN WHEAT: A MAP OF HERBICIDE RESISTANCE Since the years 1990, the spread of herbicide resistance in wheatis more and more important within weed species as blackgrass (Alopecurus myosuroidesHuds,). Resistanceto the fenoxaprop-P-ethyl within blackgrass population wasfirst was detected in the Côte d'Or departement. ln this context, a map of the herbicide resistance of blackgrass was undertaken at the scale of this departement. 149 fields were used for this study with for each an agronomic investigation and harvests of blackgrass seeds. Almost the whole of the populations of blackgrass tested present at least 50% of plants resistant to fenoxaprop-P-ethyl, and 53% and 9% of these populations respectively contain at least 50% of plants resistant to flupyrsulfuron-methyl and the clodinafop-propargyl. Only one population is resistant to isoproturon.Depuis les années 1990,les phénomènes de résistances aux herbicides se développent chez des mauvaises herbes importantes comme le vulpin (Alopecurusmyosuroides HudsJ pour la culture du blé. La Côte-d'Or a été le premier département où fut détectée de la résistance au fénoxaprop-P-éthyl chez le vulpin. Dans ce contexte, une carte de la résistance du vulpin aux herbicides a été entreprise à l'échelle de ce département. Au total,149 parcelles ont été utilisées pour l'étude avec pour chacune une enquête agronomique et des récoltes de semences de vulpin. La quasi-totalité des populations de vulpin testées présentent au moins 50% de plantes résistantes au fénoxaprop-P-éthyl, et 53% et 9 %de ces populations contiennent au moins 50%de plantes résistantes respectivement au flupyrsulfuron-méthyle et au ciodinafop-propargyl. Une seule population a été détectée comme résistante à l'isoproturon en Côte-d'Or

Weed-DATA Base de données ‘Traits’ des plantes adventices des agroécosystèmes

SPEEAECOLDURGEAPSIéquipe CAPAabsen