The first project is led by Jörg-Peter Schnitzler and aims to analyze the contribution of aquaporins to the water use efficiency of poplar. Aquaporins are integral membrane proteins that control water flow across cellular membranes and play multiple roles in all aspects of plant-water relations. Additionally, some of them transport also other small uncharged solutes (glycerol, CO2, ammonia and urea). Within the project transgenic poplars up- and down-regulated in gene expression of ‘Plasma membrane Intrinsic Proteins’ (PIP) will be generated and used in laboratory and greenhouse experiment to elucidate the contribution of these pores to the water transport and transpiration of poplar under well-water and water-limited conditions. Moreover, this project analyses the emission of volatile organic compounds (VOC) – in particular isoprene - of poplar hybrids at the experimental SRC. Isoprene is a highly reactive volatile hydrocarbon with significant impact on the chemistry of the lower troposphere, particularly influencing photosmog (ozone) and aerosol formation. Poplars belong to the strongest emitters of isoprene. Within PRO-BIOPA we quantify the emission of VOC from SRC and will estimate the emission potential of different commercially used poplar hybrid clones.
Due to the move of the working group to Munich the subproject is now running at the Department of Environmental Engineering (EUS) Helmholtz-Zentrum München. For more information see website of EUS
The second project of IMK-IFU is led by Klaus Butterbach-Bahl and Hans Papen and analyses the emission of GHG and C and N matter flux from poplar plantations. Using dynamic soil chamber systems seasonal fluxes of CO2, methane and N2O will be quantified on our poplar plantation in dependence of the water and nutrition regimes. In addition, C and N storage / exchange in soils will be quantified.
For the simulation of C and N turnover and associated matter exchange with the atmosphere (GHGs) and hydrosphere (leachates) at our poplar SRC as well as on a regional scale (Germany), we will apply process-based models from the Denitrification-Decomposition (DNDC) family i.e. ForestDNDC (previously called PnET-N-DNDC). In addition, we will use the biochemical process-based isoprenoid emission model SIM-BIM to simulate VOC emissions from poplar. Both models are implemented in MoBILE (Modular Biosphere Simulation Environment), a framework to link 1-dimensional biosphere models at single sites or in multi-site mode in conjunction with a GIS.
Based on experimental data and model simulations we will generate a complete trace gas balance for poplar short rotation plantations.
In combination with the life-cycle-assessment (netto energy balance) we will develop criteria that should be taken into account for a sustainable bioenergy production with fast growing poplar plantations.