Search results for "interactions."
showing 10 items of 1865 documents
Etude des interactions plantes-microbes et microbes-microbes au sein de la rhizosphère, sous un aspect coûts-bénéfices, dans un contexte de variation…
2013
Understanding the interactions that bind plants and soil microorganisms is an essential step for the sustainable management of ecosystems, especially in agriculture. The ecosystem services resulting from such interactions include plant productivity which responds, in part, to the food requirements of the world's population and the regulation of biogeochemical cycles. These ecosystem services depend on trophic links between the two partners in the interaction and can be represented by a tradeoff between the costs and benefits for each partner. Plants, being autotrophic organisms or primary producers, are key organisms which introduce carbon into the ecosystem, through photosynthesis. Part of…
Impacts of climate change on the performance of an insect pest and associated consequences for tritrophic interactions
2019
Global warming poses a major challenge to living organisms, particularly for ectothermic animals like insects, whose physiology and behaviour are closely related with direct thermal surroundings. This thesis aims at experimentally investigating the impacts of climate change on the overall performance of a major grapevine pest, the European grapevine moth (Lobesia botrana), and the associated consequences for interactions involving this phytophagous insect and adjacent trophic levels, more specifically natural enemies (parasitoids). The experiments conducted focus on three facets of climate change: an increase in mean temperature, an alteration of daily thermal range, and the occurrence of h…
Les comportements préalables à la prise lactée chez le souriceau : caractérisation de sécrétions maternelles réactogènes et implication de l'expérien…
2012
Birth is one of the most delicate periods mammalian infants have to deal with. Newborns have then to adapt physiologically and behaviorally to the aerial environment, and one of their first challenges is to ingest colostrum and milk. It is paradoxical that the survival of pups is conditioned by the success of this first suckling, and that we have so little understanding of the stimuli that underlie and promote it. Thus, the present work aims to contribute to answer how immature and naïve newborns do manage to orient to a nipple, to grasp it, and to suckle efficiently? This general issue will be addressed in the mouse in focusing on: i) the nature of the chemical substrates that newborn mice…
A study on texture-taste-aroma interactions: physico-chemical and cognitive mechanisms
2009
International audience; Texture–taste, texture–aroma and aroma–taste interactions were examined in custard desserts varying in viscosity (at identical composition), sucrose level and aroma nature. All reciprocal interactions were investigated, with each binary interaction addressed through an independent sensory study. Rheological, in vivo aroma release and sucrose release measurements were run in parallel to control for a possible physico-chemical origin of these interactions. Observed interactions were found to be dependent upon the nature of the sensory modalities involved; physico-chemical mechanisms could only in some instances entirely explain these interactions. Taste and aroma did n…
Réponse des interactions plante-sol aux régimes de précipitations
2018
Water availability governs terrestrial nutrient cycles by impacting the functioning of both plants and of soil microorganisms. The predicted changes in precipitation patterns (i.e. the magnitude and frequency of precipitation events) associated with climate change, will thus likely have important consequences on ecosystem functioning. Dry and seasonally dry ecosystems are particularly vulnerable to changes in precipitation patterns, as they are already constrained to a large extent by water availability. However, more mesic systems may also experience dry periods that may impact plant-soil functions. In this thesis, experiments in soil-only systems and plant-soil systems were used to gain i…
Genes encoding transcription factors in Glomus intraradices and their expression at the appressoria stage of arbuscular mycorrhiza interactions
2007
International audience; Molecular pathways governing the life cycle of arbuscular mycorrhizal (AM) fungi and their symbiotic interactions with root tissues are not yet fully understood. Most studies fo fungal responses to host plants have targeted developmental stages before root contact (germinating spores), or after root colonization (intraradical mycelium). We are focusing on the early cell events of appressoria contact with the root surface which are essential to the successful outcome of the AM symbiosis. Recent monitoring of Glomus intraradices gene expression at this stage has revealed differential fungal responses to roots of host and non-host (Myc- mutants) M. truncatula (Seddas et…
Membrane dynamics of sugar transports in tobacco-microbe interactions
2017
SPEINRAUBIPM DOCT; Plants can influence microorganism population through exudation of sugars notably as carbon source. Indeed, the type of plant-microorganism interaction (PMI) is linked to the trophic exchanges between plant and microorganism. Microorganisms are thus able to “manipulate” the host to modify sugar fluxes. In mycorrhizal symbiosis, the plant has a supply of nutrients by the fungal partner, which in return receives sugars. In pathogenic relationship, the microorganism will divert sugars provided by the plant without compensation. Despite identification of sugar transporters at biotrophic interfaces, molecular and cellular mechanisms by which microorganisms operate the distribu…
Legacy effects of contrasting water and N-availability patterns on plantmicrobial response to rewetting
2019
National audience; Introduction. Shifts in the frequency and magnitude of rain events (precipitation regime) associated with climate change may affect plant morphological and physiological strategies as well as soil microbial activity.Objectives. The objective of this study was to determine i) how precipitation history shapes the response dynamics of soil bacterial and fungal communities to rewetting, as well as plant-microbial competition for N, and ii) how the N status of the system may modulate the effect of precipitation regime.Materials & methods. The legacy effects of 12 weeks of contrasting precipitation (frequent or infrequent watering, equal total water input) and N inputs was asse…
Qu'est-ce que les bandes enherbées? conséquences environnementales et biologiques
2009
National audience
Effets des interactions entre diversité végétale inter et intraspécifique et communautés microbiennes du sol sur les propriétés de l’écosystème - Can…
2019
National audience; Le lien entre diversité et fonctionnement d’un écosystème ainsi que les mécanismes sous-jacents sont très étudiés en génétique des populations et en écologie des communautés et des écosystèmes. La première s’attèle à décrire les effets de la variabilité génétique intraspécifique sur différentes propriétés écosystémiques tandis que la deuxième s’intéresse aux interactions écologiques au niveau interspécifique. Notre objectif est de faire le lien entre ces deux champs disciplinaires par l’étude des effets conjoints d’une mobilisation de la diversité végétale intra et interspécifique et de la diversité microbienne sur les propriétés de l’écosystème. Nous avons mesuré différe…