P3 - Tree Physiology (N-Metabolism)
The significance of N-uptake and
metabolism for the competition for N in the rhizosphere. - Institute of
Forest Botany and Tree Physiology, University Freiburg.
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 the 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-fertilization, C-supply, competing understorey, and mycorrhization on N-uptake, -metabolism, and -partitioning as well as the N-nutrional 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.
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 the 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-fertilization, C-supply, competing understorey, and mycorrhization on N-uptake, -metabolism, and -partitioning as well as the N-nutrional 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.