BIOLOGY AND LIFE CYCLE OF A MUSHROOM
Mushrooms are very interesting organisms. Biologically speaking, they are more closely related to animals than they are to plants. Similarly to animals, they get their nutrients by digesting and absorbing food. They 'breathe' oxygen in and CO2 out.
Their food is the substrate that they are growing in. This is commonly wood, manure, or soil. The mycelium (the 'body' or 'roots' of the mushroom) grows through this substrate and excretes enzymes to convert it into an absorbable form.
There are four basic stages to the life cycle of a mushroom: Spore germination, colonisation, fruiting, and sporulation. The process is easy to understand if you look at it one step at a time.
Like a plant seed, a mushroom spore germinates (sprouts) when the environmental conditions are right. Usually, this involves high humidity, plus a favourable temperature for that particular species.
When the spore germinates, a strand of mycelium emerges from it. The strands of mycelium spreads through a substrate, gathering water and nutrients, to be able to produce fruiting bodies (the mushrooms themselves).
This process of mycelium spreading through a substrate is called colonisation.
Mycelium slowly spreads through its substrate, trying to colonise as much area as possible. The more substrate that a single body of mycelium has colonised, the greater its access to nutrients, and therefore the greater its capacity to produce lots and lots of fruiting bodies (mushrooms) to continue to produce spores and procreate.
Once the body of mycelium has gained access to enough nutrients, certain environmental conditions will trigger the formation of fruiting bodies, better known as mushrooms.
These environmental conditions vary from species to species, but commonly involve high humidity and a slight drop in temperature, which is one reason why mushrooms are the most abundant in autumn.
The first stage of a mushroom fruit body is called a hyphal knot. This is when the individual strands of hyphae bundle together and prepare to grow a mushroom.
From there, a small cluster of visible bumps form on the surface of the mycelium. As they grow, they begin to look like miniature mushrooms just a few millimetres in size, known as primordia. These are commonly called ‘pins’ in the cultivation world.
From this point, provided humidity and temperatures remain favourable, the pins continue to grow into full size mushrooms. Depending on temperatures, and the individual species, this process of a pin growing into a full size mushroom can take anywhere between two days to a week or longer.
As the mushroom fruit body matures, gills (or pores in some cases) begin to become visible on the underside of the mushroom. Some mushrooms have a ‘veil’ or a ring around the stem protecting the gills during early growth. But eventually as the cap of the mushroom grows, the gills become exposed and begin to release spores.
Sometimes spores can be released in such vast quantities that they appear as wisps of smoke wafting from the mushrooms gills. It is also common for spore deposits to be visible on the ground (or log) around the mushroom.
Spores are so small that they are easily carried away in air currents, and once airborne they are capable of travelling vast distances including thousands of kilometres across oceans and continents, just waiting to land in a favourable place to germinate and continue through the life cycle once again.