Project R-4546

Hydraulic lift via mycorrhizal fungi: a key factor in the competition for organically bound nutrients? (Research)

Hydraulic lift is the transportation of water from moist to drier soil parts through the plant root system. There are growing indications that symbiotic ectomycorrhizal (EcM) fungi are benefiting from this effect. Besides access to photosynthetic products of the host tree, additional availability to water would be an important factor in the competition for nutrients with other soil organisms. Studies about the influence of EcM fungi on free-living fungi and organic matter dynamics are scarce. In this study, by using advanced microcosm and pot systems, we want to examine interactions between EcM and free-living fungi and their impact on N-mobilization and transformation of organic matter. In two-dimensional axenic systems we can observe myceliumdevelopment and -interaction in situ up to hyfenlevel. Dynamics of stable isotopes can investigated up to spatial and temporal detail level. As a nitrogen source, we can use peptides that may or may not be complexed with tannins. In larger pot experiments we initiate hydraulic lift. The use of rotating cylinders makes it possible to create compartments, within a system, with and without symbiotic fungi. The cylinders can be filled with more or less recalcitrant organic material. This makes it possible to isolate the effects of EcM fungi on organic matter decomposition and transformation.

01 October 2009 - 30 September 2012