Function of mycorrhiza in the competition for water and nitrogen

本研究旨在研究山毛榉（Fagus sylvatica L.）外生菌根（EM）群落对氮获取的功能，并了解干旱对这些功能的影响。15N标记将用于研究山毛榉植物和外生菌根在田间控制条件下的氮吸收，以探索EM 15N富集与植物氮吸收之间的关系。来自一系列干燥和潮湿地点的特定地点EM群落将被合成。干旱胁迫将作为调节根系碳供应的一种手段，从而影响EM的竞争关系。EM将按物种收集，并确定其丰度，并与n吸收有关。为了剖析菌根效应，非菌根山毛榉也将被研究。将分析受控实验EM-beech与选定真菌物种的关联，以确定在水分充足和干燥的条件下，不同EM物种向beech提供N的能力是否存在差异。

The goal of this proposal is to investigate the function of ectomycorrhizal (EM) communities for nitrogen acquisition of beech (Fagus sylvatica L.) and to understand how these functions are affected by drought. 15N labelling will be used to investigate N uptake of beech plants and ectomycorrhizas under field und controlled conditions to explore relationships between EM 15N enrichment and plant N uptake. Site-specific EM communities from a range of dry and moist sites will be synthesized. Drought stress will be applied as a means to modulate carbon supply to roots, thereby affecting the competitive relations of EM. EM will be collected according to species and their abundance will be determined and related to N-uptake. To dissect the mycorrhizal effect, non-mycorrhizal beeches will also be studied. 15N enrichment and uptake rates will be analysed in controlled experimental EM-beech associations with selected fungal species to find out if differences in the abilities of different EM species exist to supply beech with N under well watered and dry conditions.