Search results for "Vegetal Biology"

Changing agricultural practices modifies the species and trait composition of the weed flora. A simulation study using a model of cropping system eff…

2012

International audience; Cropping systems change to adapt to socio-economical and environmental constraints (e.g. simplified tillage) and to profit from technological innovations (e.g. genetically-modified crops). These changes can result in unexpected side-effects which are difficult to determine in fields. The objective of the present study was to use a model, FLORSYS, to evaluate such impacts ex ante on weeds. FLORSYS quantifies the effects of crop succession, management techniques and climate on multi-specific weed dynamics over the years; it was parameterized with functional relationships predicting model parameters (e.g. seed mortality) from species traits (e.g. seed coat thickness). C…

Ex ante evaluation of gene flow in oilseed rape with cropping sytem models

2009

International audience

Loss in microbial diversity affects nitrogen cycling in soil

2013

National audience; Microbial communities have a central role in ecosystem processes by driving the Earth’s biogeochemical cycles. However, the importance of microbial diversity for ecosystem functioning is still debated. Here, we experimentally manipulated the soil microbial community using a dilution approach to analyze the functional consequences of diversity loss. A trait-centered approach was embraced using the denitrifiers as model guild due to their role in nitrogen cycling, a major ecosystem service. How various diversity metrics related to richness, eveness and phylogenetic diversity of the soil denitrifier community were affected by the removal experiment was assessed by 454 sequen…

Résistances aux herbicides: cible et non-cible, une menace pour le désherbage d’automne des céréales ?

2019

La résistance aux herbicides peut évoluer via deux mécanismes: d’une part une résistance « liée à la cible », causée par une mutation et spécifique d’une famille herbicide, et, d’autre part, une résistance « non liée à la cible », moins spécifique, permettant par exemple une détoxication de diverses molécules. Des simulations montrent que l’évolution de résistance non-cible en réponse aux applications d’herbicides est très probable mais peut rester longtemps inaperçue car lente. En céréales d’hiver, le désherbage chimique des graminées est rendu problématique par l’évolution de résistance à la fois cible et non-cible aux herbicides de sortie d’hiver, ce qui impose un recours accru aux appli…

Occurrence of non-target-site-based resistance to ALS inhibitors in the broadleaf weed Papaver rhoeas (corn poppy).

2013

The vast majority of reported cases of resistance to ALS inhibitors in broadleaves is due to the selection of mutant, herbicide-resistant ALS alleles carrying a mutation at one of a few ALS codons that can be easily identified (ALS-based resistance). Non-ALS-based resistance (non-target-site resistance, NTSR), considered to be endowed by differences in the expression of many genes, has essentially been reported in grasses and hardly ever in broadleaves. We investigated NTSR to ALS inhibitors in poppy by pairing plants resistant to ALS inhibitors with susceptible plants and subsequently analysing the segregation of resistance in F1 families. Poppy plants resistant to ALS inhibitors were geno…

Nitrogen cycling microbial communities: from diversity to interactions and functions

2019

Soil microorganisms form one of the largest biodiversity reservoirs on earth. They also play essential roles in ecosystem functions such as biogeochemical cycling. However, the importance of microbial community diversity and composition for ecosystem functioning is still debated. A sound understanding of the ecological processes governing the assembly of these communities in the environment is also missing. In this talk, I will give examples of how we addressed these knowledge gaps using nitrogen cycling microorganisms as model functional guilds. Nitrogen is the most limiting nutrient for crop production in agriculture. The nitrogen cycle is also one which was pushed by human activities out…

Impact des systèmes de culture en protection intégrée contre les adventices sur l'intensité des émissions de N2O par les sols

2013

Utilisation de la technique du FRAP pour évaluer la fluidité de la membrane plasmique de cellules végétales en suspension

2014

Species-specific prey choice of carabid beetles in European cereal fields

2017

National audience; Trophic interactions between species in agroecosystems provide key regulation ecosystem services and therefore also determine the dynamics, robustness and resilience of service provision. To achieve international goals of reducing application of pesticides without compromising key provisioning ecosystem services such as crop yield, recent research attaches importance to the biological control potential of carabid beetles. However, apart from feeding on pest species and weed seeds, carabids also consume non-pest prey (alternative prey) such as collembolans and earthworms, which can play a contradictory role in the efficacy of pest and weed control. Most carabids are descri…

Qu’attendre des recherches en microbiologie du sol ?

2014

SPE EA EcolDur GenoSol MERS IPM Résumé du livre : La fertilité des sols est au carrefour des enjeux de sécurité alimentaire, de protection de l’environnement et de rentabilité économique de l’activité agricole. Cet ouvrage présente les résultats d’une réflexion prospective sur le contexte de la fertilisation dans les 5-10 ans à venir. Il définit les besoins en termes de méthodes et d'outils pour la gestion des cycles biogéochimiques et le raisonnement de la fertilisation en agriculture. Mots clés du livre : agriculture - agronomie - eau - effluent - engrais - environnement - fertilisation - pollution - prévention - production végétale - prospective - sol Description du chapitre 10 (partie 3…