ABSTRACT
Arbuscular mycorrhizal (AM) fungi have coevolved with plants and soils for over 400 million years to become part of the root system of a very large number of terrestrial plant species (Taylor et al., 1995) and the “backbone” of the soil (Barea, Azcon, and Azcon-Aguilar, 2002). At some point in evolution, other types of mycorrhizal associ ations appeared under the selection pressure of their environment (Read and Perez-Moreno, 2003). While certain plant species, partic ularly primary colonizing species, are known to be non-mycorrhizal (Janos, 1980), it is a fact that most of today’s terrestrial plant species use leaves to fulfill their C needs and mycorrhizae to take up water and nutrients.
