Interactive Primary Newsletter 32 Let there be light & Fungus features

The Fungal Kingdom                Kit suppliers Living things are classified into five Kingdoms, one of which is the Fungal Kingdom. Fungi are another group of living organisms that can be entertaining and informative in the classroom. One common misconception is that fungi are plants. Plants are autotrophs i.e. they can make their own organic food from simple inorganic materials. They do this by the process of photosynthesis. Fungi are heterotrophs i.e. they need a source of food (complex organic material) which they can break down to obtain energy and the building blocks for their growth. There is a wide variety of fungi available in the shops, perhaps the most familiar being edible mushrooms. The most common of these is the ‘field or white mushroom’ (Agaricus bisporus). In the wild, mushrooms usually grow in fairly specific habitats where they break down dead and decaying plant materials. Commercial cultivation takes place on a compost of cereal straw and animal manure under strictly controlled conditions such as in polytunnels or caves as in Derbyshire or Saumur in France. The Oyster Cap mushroom (Pleurotus ostreatus) can be grown successfully in the classroom. These mushrooms are edible and are readily available in supermarkets. They are grown commercially on logs, a replication of the natural process. This takes 3 to 5 years but a recent innovation allows intensive growing in a compost of sawdust and agricultural wastes. A quick, simple and cheap method of growing Oyster Cap mushrooms, one which is suitable for the classroom, is shown in Figs 5 and 6. This method uses a new toilet roll as the growing medium. The toilet paper, which consists mainly of cellulose, provides the complex organic food source for the fungus. The edible part of the Oyster Cap mushroom, the fruiting body, appears within a month. The kit and full instructions are available from the National Centre for Biotechnology Education (NCBE), School of Food Biosciences, The University of Reading,Whiteknights, PO Box 226, READING, RG6 6AP.                Figure 5 -  A good crop                                                                                      Figure 6 - A different crop The life cycle of a fungus begins with a spore that grows when conditions are just right. Out of the spore wall grows a hypha that looks like a clear, microscopic fingertip. Hyphae grow and branch to form a network of threads collectively called the mycelium. The mycelium extends through soil or living and dead organisms. When growing conditions are appropriate, the mycelium develops fruiting bodies. Mushrooms and toadstools are example of fruiting bodies. It is these that produce and release spores. Fungi find nutrition in a number of ways. Some act as parasites and feed on living material, usually doing some harm to their host (Figures 7 and 8 illustrate Bracket or Shelf fungi, the class Basidiomycetes, which can damage cut logs and standing timber). The Oyster mushrooms shown in Figs. 5 and 6 are an edible form of bracket fungi.           Figure 7 - Bracket fungus, off the shelf                                                     Figure 8 - Class Basidiomycetes (Bracket fungus) Many fungi associate with plant roots to the benefit of both plant and fungus. One particular strain forms an association with birch, aspen and conifers throwing thick coats of mycelia around the rootlets, thereby transferring minerals and other materials from the soil into the roots of the tree. In return the plant host supplies the fungus with sugars and vitamins. Yet other fungi are useful in decomposing dead plant and animal matter; they act as recyclers of organic matter, obtaining food and energy from this material and recycling nutrients such as carbon and nitrogen. Hyphal tips secrete enzymes that digest organic materials and release the products into the surrounding environment. Such saprophytic fungi can often be seen on dead leaves, logs and other plant litter. Kit suppliers There are other suppliers of ‘educational’ mushroom kits; Ragman's Lane Farm sell inoculated birch logs, one for £16.50 or two for £24.50 including postage. They are at Lower Lydbrook, GL17 9PA, Telephone 01594 860 244. E-mail info@ragmans.co.uk An American site offers a selection of kits growing on different composts, the prices from about $24 and will deliver to the UK. Do remember that inoculated logs take a long time to come to harvest. The minimum is usually about six months.