David Beeson, 28 February 2022
Fungi are everywhere and are said to be found higher in the atmosphere than any other organism. Indeed, with their light spores spreading so easily some species can be potentially found worldwide.
There are over 50 000 fungal species and they occur everywhere – land, soil and water.
They are exceptional organisms, being neither plant nor animal nor something in between! They are themselves and quite original.
They can be unicellular – bread yeast, for example, or have a complex structure like the Lion’s Mane (see later). They contain no photosynthetic pigments and are animal-like in their feeding, in that they secrete digestive enzymes to breakdown organic material that can then be used as body fuel – for energy release or as building blocks. Most fungi are composed of fine threads (hypha) with no cross cellwalls, scattered nuclei and other organelles. The hyphae penetrate their substrate and form the mass of hyphae called the mycelium.
Many fungi are associated with other living organisms. Some live on and within the roots of plants forming a mutualistic relationship (also called symbiotic relationship) to form a mycorrhiza. Others join with algae to form lichens.
The ‘mushroom’ that we see is a spore-producing structure that is the main means of dispersal. The spores may come from the gills (but that is not universal). Spores can be sexual or asexual in their origin.
Each spore is a single cell, so small it cannot be seen with the naked eye. It is surrounded by a hard outer wall, resistant to desiccation and other extreme conditions.
I used fungal reproduction in an ascomycete to show the process of ‘meiotic crossing-over’ with my students. For, during the production of gametes (meiosis) the chromosome number is reduced and chromosomes do break and reform in new genetic combinations – really important in producing variation and driving evolution. Try: https://www.youtube.com/watch?v=Zbdhm8Be1VA
Fungi are of considerable importance to humans. Potato blight fungus (Phytophthora infestans) can wreak havoc among crops. There are many other parasitic fungi, including Athlete’s Foot and Thrush. Saprophytes are vital in organic recycling in the soil and sewerage works, mushrooms are edible and yeast is employed in beer, wine and bread production. Some fungi produce antibiotics to fight off bacterial combatants for their food sources … and humans can exploit that function.
I’m growing my own fungi.
- At one time I imported spent mushroom compost to enhance the humus content of my garden soil. That ensured several years when free cultivated mushrooms were available from the soil. Inevitably, spores reached the lawn and mushrooms occur still.
- I grow yeast before embarking on bread making at home, and in the past I used it for beer and country wine production. (The wine was hardly drinkable!) (On one occasion, quite illegally, I distilled off the ethanol from my wine. I carefully ignored the methanol that comes off first, and collected the distillate that boiled off at 78 degree Celsius. The mistake I made was to store my home-made hooch in a rubber stoppered flask. The alcohol attacked the rubber and made it undrinkable. Woops. I should have used cork.) (While that distillation is illegal, you can generate an enhanced alcohol content of wine in another, legal, method. If you place your wine in a shallow tray in the freezer it will freeze. If you take it out, allow it to thaw slightly and collect that liquid – it will be alcohol enhanced!)
- By mistake I have grown Mucor hiemalis, the familiar bread mould! To try for yourself, just leave some moistened fresh bread out in a suitable location and await the white downy growth. The universality of spores will ensure rapid colonisation of the starchy food. Mucor’s hyphae will soon release amlase enzymes to break the starch to maltose and glucose and it will grow rapidly, soon throwing up spore-producting sporangia. (If you chew non-sweet bread for a short while your own salivary amylase will release the same maltose and glucose, and the bread tastes sweet.)
- Now I have just started to grow edible fungi from a kit sold (in the UK) by the Rustic Mushroom Company. Hericium erinaceaus, The Lion’s Mane or Hedgehog fungus, and Laetiporus sulpheureus, Chicken-of-the-Woods, have been innoculated into freshly-fallen logs.
I’m using freshly cut field maple logs about 1m long, drilling holes and then inserting the supplied fungal culture. The logs have been left in damp locations with soil contact. I’m told I have to wait at least a year before ‘fruiting bodies’ occur.
Other fungal kits are available to grow on woodchip. E.g. https://woodyfuel.co.uk/wood-chip-mushrooms-growing/
Interested in Green Plants, Fungi and their friends? I’ve an excellent old book that may still be available somewhere: T J King’s Green Plants and their Allies. Guess there must be modern equivalents. Remember EBAY has really cheap ex-university textbooks.
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