Responses of arbuscular mycorrhizal fungi to nutrient additions in Southern Ecuador

该项目嵌入PAK 823和N循环束，旨在提高热带山地森林系统中相对贫乏的丛枝菌根（AM）知识，特别是将菌根反应整合到厄瓜多尔南部研究地点正在进行的营养调控（NUMEX；营养调控实验）中。在此框架内，我们基于资源平衡模型检验了AM真菌在根和土壤（根外菌丝）中丰度的假设。利用分子生态学工具（焦磷酸测序），我们测试了根系中AM真菌组合的差异，以响应营养操纵和海拔梯度。在N循环束内，我们协调联合旋转核心实验，我们可以关闭菌根的影响，以了解这些真菌对N循环的影响。此外，我们还参与了联合15-N标记实验。我们希望这项工作将对我们对这个热带系统的AM和N循环的认识做出决定性的贡献。

The goal of this project, embedded in PAK 823 and the N cycle bundle, is to enhance the comparatively poor knowledge about arbuscular mycorrhizas (AM) in tropical mountain forest systems in general, and in particular to integrate mycorrhizal responses into ongoing nutrient manipulations (NUMEX; NUtrient Manipulation EXperiment) at the research site in Southern Ecuador. Within this framework, we test hypotheses about the abundance of AM fungi in roots and in the soil (extraradical hyphae) based on the resource balance model. We build on our previous measurements showing rapid responses to fertilization, especially N. Using molecular ecology tools (pyrosequencing) we test for differences in AM fungal assemblages in roots in response to nutrient manipulations and along elevational gradients.Within the N cycle bundle, we coordinate the joint rotated core experiment, in which we can switch off the mycorrhizal influence in order to learn about the effect of these fungi on the N cycle. In addition we contribute to the joint 15-N labeling experiment. We hope this work will make a decisive contribution to our knowledge of AM and the N cycle in this tropical system.