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Mycelium (plural
mycelia) is the
vegetativeVegetative reproduction is a type of asexual reproduction for plants, and is also called vegetative propagation, vegetative multiplication, or vegetative cloning. It is a process by which new plant "individuals" arise or are obtained without production of seeds or spores...
part of a
fungusA fungus is any member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. The Fungi are classified as a kingdom that is separate from plants, animals and bacteria...
, consisting of a mass of branching, thread-like
hyphaA hypha is a long, branching filamentous cell of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or more...
e. The mass of hyphae is sometimes called
shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or in many other substrates. Typically a single spore germinates into a monokaryotic mycelium which cannot reproduce sexually; when two compatible monokaryotic mycelia join and form a dikaryotic mycelium, that mycelium may form
fruiting bodiesIn fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are born...
such as
mushroomA mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus, hence the word mushroom is most often applied to those fungi that have...
s. A mycelium may be minute, forming a colony that is too small to see, or it may be extensive:
It is through the mycelium that a fungus absorbs
nutrientA nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. Nutrients are the substances that enrich the body. They build and repair tissues, give heat and energy, and regulate body processes...
s from its environment. It does this in a two stage process. Firstly the hyphae secrete enzymes onto the food source, which breaks down polymers into monomers. These monomers are then absorbed into the mycelium by
facilitated diffusionFacilitated diffusion is a process of diffusion, a form of passive transport facilitated by transport proteins. Facilitated diffusion is the spontaneous passage of molecules or ions across a biological membrane passing through specific transmembrane transport proteins...
and
active transportActive transport is the mediated process of moving particles across a biological membrane against a concentration gradient. If the process uses chemical energy, such as from adenosine triphosphate , it is termed primary active transport. Secondary active transport involves the use of an...
.
Mycelium is vital in terrestrial and aquatic
ecosystemAn ecosystem is a system of interdependent organisms which share the same habitat, in an area functioning together with all of the physical factors of the environment. Ecosystems can be permanent or temporary. Ecosystems usually form a number of food webs...
s for its role in the
decompositionDecomposition is the process by which tissues of a dead organism break down into simpler forms of matter. The process is essential for new growth and development of living organisms because it recycles the finite matter that occupies physical space in the biome. Bodies of living organisms begin to...
of plant material. It contributes to the organic fraction of soil and its growth releases
carbon dioxideCarbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state...
back into the atmosphere. The mycelium of
mycorrhizaA mycorrhiza is a symbiotic association between a fungus and the roots of a plant. In a mycorrhizal association, the fungus may colonize the roots of a host plant, either intracellularly or extracellularly...
l fungi increases the efficiency of water and nutrient absorption of most plants and confers resistance to some plant pathogens. Mycelium is an important food source for many soil invertebrates.
Sclerotia are compact or hard masses of mycelium.
Uses
One of the primary roles of fungi in an ecosystem is to
decomposeDecomposition is the process by which tissues of a dead organism break down into simpler forms of matter. The process is essential for new growth and development of living organisms because it recycles the finite matter that occupies physical space in the biome. Bodies of living organisms begin to...
organic compounds.
PetroleumPetroleum or crude oil is a naturally occurring, flammable liquid found in rock formations in the Earth consisting of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds.The term "petroleum" was first used in the treatise De Natura Fossilium, published in...
products and
pesticideA pesticide is a substance or mixture of substances used to kill a pest.A pesticide is any substance or mixture of substance intended for:- preventing, destroying, repelling or mitigating any pest....
s that can be contaminants of soil are organic molecules. Fungi therefore should have potential to remove such
pollutantA pollutant is a waste material that pollutes air, water or soil.Three factors determine the severity of a pollutant: its chemical nature, the concentration and the persistence...
s from the soil environment, a process known as
bioremediationMycoremediation is a form of bioremediation, the process of using fungi to return an environment contaminated by pollutants to a less contaminated state...
.
Mycelial mats have been suggested (see
Paul StametsPaul Stamets is an American mycologist, author, and advocate of bioremediation and medicinal mushrooms.-Research and advocacy:...
) as having potential as biological filters, removing chemicals and
microorganismA microorganism or microbe is an organism that is microscopic...
s from soil and water. The use of fungal mycelia to accomplish this has been termed "
mycofiltrationMycofiltration is the process of using mushroom mycelium mats as biological filters. The term was coined by mycologist Paul Stamets.Stamets originally came up with the technique to control E. coli in the water outflow from his property. After planting a mushroom bed in the gulch where the water was...
".
Some Mycelium has symbiotic property with many plants. This opens the door to soil supplementation to improve crop yields.
Mycelium, spread on logging roads acts as a binder holding new soil in place and preventing washouts until woody plants can be established.
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