The Significance of Plant Nitrogen Uptake and Metabolism for the Competition for Nitrogen in the Rhizosphere

该项目的目的是表征和量化的意义，植被成分（老生长山毛榉，自然再生，其他下层）在竞争中的N植物和微生物之间的山毛榉为主的森林。为此，将在空间和时间上研究竞争模式以及分子和生理背景。这些研究包括确定的吸收速率和吸收动力学的NH 4+，NO3-，氨基酸和氨基糖，结合基因的表达分析的N-转运蛋白和N代谢酶在山毛榉在共同的领域网站。在田间试验和受控条件下（温室和植物生长室），将分析供水、N-施肥、C-供应、竞争性下层植物和菌根化对N-吸收、N-代谢和N-分配以及N-营养状况的影响。将确定叶与根凋落物作为山毛榉再生的氮源的意义。在实验室试验中，将研究根际气相中NO和CO2浓度变化对氮吸收和代谢的影响。所取得的成果将有助于系统的理解，并将部分被用作输入参数的过程为导向的建模竞争N在不断变化的环境。

This project is aimed to characterize and quantify the significance of vegetation components (old growth beech, natural regeneration, other understorey) in the competition for N between plants and microorganisms in beech-dominated forests. For this purpose, competition pattern as well as the molecular and physiological background will be studied in space and time. These studies include the determination of uptake rates and uptake kinetics of NH4+, NO3-, amino acids, and amino sugars, combined with expression analyses of genes of N-transporters and enzymes of N metabolism in beech at the common field sites. In experiments in the field and under controlled conditions (greenhouses and phytotrons) the effects of water supply, N-fertilisation, C-supply, competing understorey, and mycorrhization on N-uptake, -metabolism, and -partitioning as well as the N-nutritional status will be analysed. The significance of leaf vs. root litter as N source for beech regeneration will be determined. In laboratory experiments, the consequences of changing NO and CO2 concentrations in the gaseous phase of the rhizosphere on N-uptake and ¿metabolism will be studied. The results achieved will contribute to system understanding and will partially be used as input parameters for process-oriented modelling of competition for N in a changing environment.