par Meyers, Barbara 
Promoteur Olde Venterink, H
Co-Promoteur Giacomo, Santini
Publication Non publié, 2021-08-31
Promoteur Olde Venterink, H
Co-Promoteur Giacomo, Santini
Publication Non publié, 2021-08-31
Mémoire
| Résumé : | The association of plant roots with mycorrhizal fungi is omnipresent in ecosystems worldwide. Arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) fungi present anatomical and physiological differences determining important ecological processes, and particularly, nutrient cycling. To our current knowledge, most studies have focused on assessing the influence of EcM and AM trees on nitrogen (N) and phosphorus (P) cycling in temperate forest while questions concerning the distribution and role of mycorrhizal association on biogeochemical processes in tropical soils remains unclear. By combining a literature review and meta-analysis approach, this research aims at understanding the geographical distribution patterns of AM and EcM associations and their differentially impact on soil N and P cycles in tropical biomes. The research underlined that the diversity of EcM fungi in tropical systems might be underestimated as new species and hosts have been identified in the past decade. Then, the capacity of EcM trees to form monodominant stands in tropical forest is partially explained by their ability to access organic N and recalcitrant P forms in soils by secreting a wide variety of soil extracellular enzymes. Moreover, the lower soil N and P availability in EcM dominated stands further supports this enhanced capacity of EcM trees to acquire nutrient from organic matter. Finally, although AM and EcM associations were respectively related to an inorganic and organic N and P cycling at a global scale, results in tropical systems were not systematically consistent and might indicate a greater plasticity and resource partitioning of mycorrhizal fungi in tropical systems |
