What do they do for plants? These mycorrhizal fungi increase the surface absorbing area of roots 10 to 1,000 times, thereby greatly improving the ability of the plants to use the nutrients and water (fi gure 2). Estimates of amounts of mycorrhizal fi laments present in soil associated with plants are astonishing. Several miles of fungal filaments can be present in less than a thimbleful of soil.
Mycorrhizal fungi increase nutrient uptake not only by increasing the surface absorbing area of roots. Mycorrhizal fungi also release powerful chemicals into the surrounding environment that capture nitrogen, phosphorous, magnesium, iron and other plant nutrients. This extraction process is particularly important in plant nutrition, flowering and fruiting and explains why mycorrhizal inoculations have been so successful in hydroponic operations.