Laboratory and field methods for measurement of hyphal uptake of nutrientsin soil

Experimental systems for measuring nutrient transport by arbuscular mycorrh izal (AM) fungi in soil are described. The systems generally include two so il compartments that are separated by fine nylon mesh. Both roots and root- external hyphae grow in one compartment, but only hyphae are fine enough to grow through the mesh into the other compartment. Application of tracer is otopes to the soil of this hyphal compartment can be used to measure nutrie nt uptake by plants via AM fungal hyphae. Use of compartmented systems is d iscussed with particular reference to phosphorus, which is the mineral nutr ient transported in the largest quantity by AM fungi. Laboratory and field applications of the compartmentation methodology are presented with emphasi s on the functioning of native AM fungal communities. Advantages and limita tions of the method are considered and future important research directions are discussed in this context.