Séminaires d'Abdelhak EL AMRANI, Nathan VANNIER et Andreas PRINZING


Le vendredi 2 juin 2017 à 13h00, salle de conférences de l'OSUR, bâtiment 14b, Campus de Beaulieu, UR1

Le vendredi 2 juin 2017 à 13h00, salle de conférences de l'OSUR, bâtiment 14b, Campus de Beaulieu, UR1

Does extended phenotype impact plant biodiversity in highly constrained environments?

A highly diverse plant community in a constructed wetland was used to investigate an ecological treatment system for human wastewater. The eight-year operation of the system has allowed the selection of a set of plant consortium that is convenient for plant-assisted metaremediation of wastewater. Originally, there were twenty-five plant species, some of them failed to develop and died, they were planted several times but failed to grow or to persist, especially some highly adapted plants such as Vetiver zizanioides. Hence, only seven species persisted. Interestingly, molecular phylogenetic analyses and investigation of the photosynthetic physiology showed that naturally selected plants are predominately monocot species with C4 or C4-like photosynthetic pathways. In this preliminary investigation we hypothesised that, the dramatic decrease in plant biodiversity in constrained environment may be explained by extended phenotype imposed by the C4 or C4-like photosynthetic plants.

Contact: Abdelhak EL AMRANI


Plant-plant interactions mediated by fungi impact plant fitness

It is now accepted that the large diversity of fungi living belowground is a key driver of the aboveground ecosystem functioning including vegetation composition and dynamics through nutrient cycling and symbioses. If a given plant can filter its fungal community depending on its needs and reward the best cooperators then we can hypothesize that the plant leave a fingerprint on local AM fungal propagules diversity and abundance. We used a mesocosm experiment where the plant community was mapped and changes in plants abundances were recorded over a period of 2 years at a centimetric scale. We were able to show that the root fungal community structure is determined by the of key plant species in the close plant landscape and that this relation vary across fungal taxonomic groups, ultimately impacting the focal plant performance in the plant.

Contact: Nathan VANNIER


Does demography prevent species from adapting to new environments?

Many individuals stay in their maternal environment, and many species conserve their ancestral environments (niche conservatism). Holt (1996 EvolEcolRes) hypothesized that the former results in the latter as most offspring arrives “close to home” proximate to mother individual or lineage, and is selected to succeed there. This demographic mechanism prevents species from evolving into “away” environments. We tested this ecoevolutionary feedback exposing monitor oak-seeds and seedlings at different phylogenetic distances from their mother species. Selective agents were excluded by insecticides and fungicides. Enemy pressure, mycorrhization, mortality, germination and budburst performance were observed. Tentative results suggest that indeed different phenotypes are selected “at home”, i.e. close to a closely related neighbour, than “away”, reflecting the respective enemy pressures and mutualist supports. Such differences in selection pressures between maternal and distantly related neighbourhoods might prevent the establishment of phenotypes adapted to the distantly related neighbourhood and conserve the ancestral niche.

Contact: Andreas PRINZING


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