Truffle Basics
What are truffles and what function do they have in the forest?
The majority of the world's truffles are the fruiting bodies (sporocarps) of ectomycorrhizal fungi. Ectomycorrhizal fungi (EMF) form a mutually beneficial relationship with the feeder roots of a variety of forest trees, including members of the families Betulaceae, Fagaceae, and Pinaceae. This relationship provides the heterotrophic fungi with photosynthates and improves the host tree's health and vigor by increasing water and nutrient uptake. Some EMF produce sporocarps below the surface of the ground (truffle-like fungi). In the Pacific Northwest, most truffles are found in the top few centimeters of soil at the organic soil-mineral soil interface. As these sporocarps reside in the soil, they do not use wind to disperse their spores. These fungi rely on mycophagists (fungus-eating animals and insects) for spore dispersal. Insects, mice, deer, pigs, and squirrels are just a few of the known mycophagists. Truffles attract animals to them through the production of chemically complex odors. Small mammals especially have developed a close association with truffles and are extremely adept at finding them and digging them up. When the animal eats the truffle, it ingests most of the spores. These spores remain viable through the animal's digestive tract and are expelled in feces. Precipitation then acts to wash the spores into the soil where they can germinate and continue through their life cycle.
The parts of a truffle
Peridium: the exterior sterile
covering or partial covering of the fungus.
Gleba: the spore-bearing tissue of
the sporocarp.
Columella: an internal remnant of the
stem (not always present).
