Search results for "interactions biotiques"
showing 4 items of 4 documents
The role of biotic interactions in a prey-predator system : the case of predation and regulation of weed seeds by carabids.
2020
For the transition towards agricultural production systems that are less dependent on herbicides, the use of weed regulation by seed-eating carabids is of great interest. Weed seed predation by carabids is variable and occurs within a complex context of many biotic interactions. This complexity partly explains our current inability to predict levels of in-field weed regulation. In this thesis, I analysed variations in the levels of predation and biological regulation of weeds and determined how they respond to two classes of biotic interactions: 1) the availability of alternative prey; and, 2) intra- and inter-specific interactions between the carabids themselves. Field measurements carried…
Characterisation of NO synthases from the alga Klebsormidium nitens
2022
Nitric oxide (NO) is an important cellular signaling molecule regulating various physiological processes, in both animals and plants. In animals, NO synthesis is mainly catalyzed by NO synthase (NOS) enzymes. In plants, NOS-like activities sensitive to mammalian NOS inhibitors have been measured, although no sequences encoding mammalian NOS have been found in land plants. Interestingly, we identified NOS-like sequences in about twenty algae species. These latter include the filamentous Charophyta green algae Klebsormidium nitens, a biological model to study the early transition step from aquatic algae to land plants. Currently, two NOS were identified in K. nitens genome: i) KnNOS1 which po…
L’organisation spatiale du paysage : un levier d’action pour promouvoir le service de prédation des graines d’adventices par les carabidés ?
2014
National audience; Le contexte actuel engage à développer une agriculture durable et entre autres de favoriser des services écosystémiques comme la régulation biologique des bio-agresseurs par des auxiliaires de cultures. Parmi les processus impliqués dans ces régulations biologiques, la prédation des graines d’adventices par les coléoptères carabidés opère de façon générique dans les parcelles cultivées et peut être considérée comme un service écosystémique. Elle résulte de l’action de certaines espèces ‘granivores’ spécialistes souvent peu abondantes dans les champs ainsi que de l’action d’espèces omnivores pour lesquelles les graines d’adventices peuvent représenter une ressource alterna…
Deciphering Biotic Interactions and Their Role in Soil Microbial Community Assembly and Functions
2022
Microbial communities play a key role in ecosystem functioning as well as in plant, animal, and human welfare. Their assembly relies on different processes commonly referred to as abiotic and biotic filters. Despite the widespread emphasis on abiotic filters in terrestrial ecosystems, a growing body of evidence suggests that interactions between microorganisms play a critical role in community assembly. However, the contribution of these interactions to microbial community assembly and the factors influencing them have not been clearly established. In most cases, biotic interactions between microorganisms have been investigated based on cocultures of a handful of strains, completely overloo…