• Bennett

Totally mycorrhizal dude!

Updated: Mar 5

The word mycorrhiza gets thrown around a lot especially in the marketing of plant cultivation products. Let’s take care to define just what these organisms are, what they aren’t, what they can do for us.


First let’s differentiate between mycorrhizal, pathogenic and saprophytic fungi, then we’ll get into the different types of mycorrhizae.


Saprophytic fungi— These are organisms that feed on dead organic matter. They are hugely important to the cycling of dead organic matter, building fluffy organic matter and providing plants with nutrients.


Mycorrhizal fungi— These exist in the rhizosphere of MOST plants on earth. They help the plant access water and nutrients by extending the reach and surface area of plant roots. Pests and diseases can also be avoided through the association with mycorrhizal fungi.


Pathogenic fungi?— A fungi is pathogenic when it forms a relationship that decreases plants fitness. For some fungi there is a delicate balance between helping and competing with plants, other species are purpose built to outcompete plants by infecting them in a destructive way.


Fungi usually exist as delicate strands of hyphae, connecting to form a network that can perform tasks. Some would argue that the network of fungi in soil gets so complex that it can virtually store information, and may even approach a strange form of consciousness. Every once and a while the hyphae send out reproductive structures called fruiting bodies (mushrooms!!!).


For example, oyster mushrooms are the fruiting bodies of saprotrophic fungi and chanterelle mushrooms are the fruiting bodies of mycorrhizal fungi. Sulphur shelf (below) and chicken of the woods are the fruiting bodies of fungi that parasitize trees, often times leading to host death if the infection is not compartmentalized.





There are two types of mycorrhizal fungi, and they differ in the way hyphae interact with plant cells.


>>> Endomycorrhizal fungi "infect" plant cells but instead of being destructive, they make a chemical deal with the plant to house and feed them in exchange for their services. The houses are called arbuscules and the food is in the form of starches and sugars that plants make through photosynthesis. Often times these organisms are referred to as arbuscular mycorrhizal fungi or AMF.


>>> The second type are called Ectomycorrhizal fungi because they are on the outside (ektos is greek for outside). Even from outside the cell they provide the plant with plenty of benefits by forming an extensive network around the cells, around the root zone and beyond. Big woody species that live a relatively long time form these associations; oaks, birches, roses, pines.



Chanterelle mushrooms are the fruiting bodies of fungi that are thought to form associations with tree roots.




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