Mushroom lifestyles

[jonela]

Once a mycelium is formed, it has to find a way to survive. No fungus is able to produce its own food like plants and some autotrophic bacteria do. Thus, all mushrooms must feed on organic matter (dead or alive) and are called heterotrophs.  Nevertheless, different types of mushrooms have different ways of being heterotrophs.

1. Many fungi must form a mutually beneficial relationship with a living partner, such as a tree. This symbiosis established by fungal hyphae and tree roots is called mycorrhiza. In this case the host tree (spruce, birch, oak etc.) gives the mushroom sugars, while the mushroom provides water and minerals.
Most boletes and some agarics form mycorrhizae by penetrating roots of a suitable host tree.

[jonela]

2. Other fungi, known as saprotrophs, break down dead material. Most mushrooms are able to degrade many types of dead organic matter, with the aid of enzymes which thet release externally. Some saprotrophs occur only on one substrate, others are wider in their range.

[jonela]

3. There are some mushrooms that kill plants or animals and are called necrotrophs or parasites. They live off living plants and eventually kill them. Some necrotrophs kill the host by blocking or destroying the plant's water system normally with hyphae. Others produce toxins which kill the host plant. After killing the plant, a necrothroph behaves like a saprotroph, degrading the dead plant as a substrate. Fomes fomentarius and Armillaria species are such fungi. 

[jonela]

4. Some parasitic fungi do not kill their hosts and are called biotrophs.  In this case the life processes of the host are affected and the parasite causes a disease. Rusts, mildews, ergot disease, dryrots, smuts are only a few examples.

[jonela]

Through their ability to decompose dead matter and provide the autotrophs with basic nutrients, mushrooms play a vital role in the ecological balance of the environment. They are decomposers of organic matter.

[jonela]

Another type of mutually beneficial relationship is the symbiosis between a fungus and an algae. The result of this association is a compound organism called lichen. Lichens are true life pioneers. They are able to survive in some of the most extreme environments on Earth: arctic tundra, hot deserts, rocky coasts, and toxic slag heaps.