Ectomycorrhizal impacts on nutrient uptake pathways in woody roots
2005
Taylor, J.H. | Peterson, C.A.
Ectomycorrhizae are a common symbiosis between the roots of woody plants and fungi common to the soil. That ectomycorrhizae can assist the plant partner in absorbing mineral nutrients has long been established. However, the impact of mycorrhizae on pathways available for soil nutrients to enter the root system is not clear. In particular, the impact of the fungal mantle, which surrounds the root tips, is most critical. In the present study, we assessed the permeability of the Pinus banksiana/Hebeloma cylindrosporum fungal mantle to both berberine and radioactive sulfate ions. It was found that the fungal mantle was completely impermeable to tracer dye. To test the permeability to sulfate ions, a novel technique called the internal perfusion technique was employed. By this method, permeability can be assessed. The fungal mantle proved to be impermeable to sulfate over a 24-hour exposure period. Based on recent findings pertaining to root anatomy, this result suggests that the plant may be highly dependent on the fungus to supply mineral nutrients as there is little plant tissue capable of nutrient absorption outside the fungal mantle.
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