Truffles are hypogeous fungi of the Ascomycota division, Tuberales order, Tuberaceae family and Tuber genus. This class of fungi needs to join to the thinnest roots of certain superior plants such as holm oaks, oaks, kermes oaks… without which they are unable to live naturally. This association is called symbiosis and the union between the root and hyphae of the fungus is called mycorrhize, a word that etymologically comes from the Greek words “mycos” (fungus) and “rrhiza” (root).
Fungus morphology
From a morphologic point of view, the truffle is made up of the following parts:
- Peridium. It is the peel or bark of the truffle, made up of small and tight pyramidal black warts.
- Gleba. It is the inner mass, furrowed by a series of thin creamy white veins. It is were we find the spores.
Truffles have a balloon-like shape, rough and irregular as black and subterranean tubers, variable in size and weight. Their aspect and size depend on the season: in spring you can hardly see them, in summer they are bigger in size and pale red colored and by the end of the autumn they start to mature and get brown and black with reddish spots first and totally black at the end, with a wart covered surface.
Life cycle of the truffle
The life of a truffle plantation is linked to that of the symbiont tree it lives with.
We can distinguish two stages or periods clearly differentiated at a truffle plantation. The first one is the formation of the truffle plantation, which can last between 6 and 8 years. The second period is the production itself, from 8-10 years onwards.
The forming stage is a period when the mycorrhizae spread over the whole land growing with the root of the trees. As the truffle mycelium settles in the ground and takes over it, we appreciate evident signs on the surface that are commonly known as glade or burnt areas because grass and most plants dry and the floor looses all vegetation.
Once the truffle plantation has settled, with its characteristic glade at the base of the tree, the production stage begins. The beginning of the truffle production depends on the wood species associated.
The annual cycle of a truffle plantation in the production stage is subject to this chronology:
- In spring it is the spore germination, mycelium and root spread of the mycorrhized plant, reinfestation of the roots with the fungus and high metabolic activity of the mycorrhizae.
- In summer, the fungal primordium are formed and strengthened.
- In autumn, the metabolic activity of the fungus decreases and the truffles take their final shape and size.
- In winter the metabolic activity stops, the truffles mature and they are harvested between the months of November and March.
