Key Functions of Mycelium in Ecosystems Explained
Mycelium Definition: Mycelium is a mass of branching, thread-like hyphae that make up the vegetative portion of a fungus or fungus-like bacterial colony. Shiro is a term used to describe a mass of hyphae, especially in fairy ring fungi. Mycelium-based fungal colonies can be found in and on soil and a variety of other substrates.
Mycelium Meaning:
As we already looked into the definition of mycelium, take a look at the Mycelium meaning here. Fungi's plant bodies are usually made up of branched and filamentous hyphae. Mycelium is a net-like structure formed by Mycelium Hyphae.
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Mycelium Structure
Fungal mycelia look like a cotton ball to the naked eye. A network of hyphae bundles together to form mycelia, which can be found on substrates, in the soil, or underground.
Mycelia, unlike fungal hyphae, are strongly branched, making them transparent to the naked eye. In addition to being strongly branched, they have also been shown to be ishighly septate, meaning that septa divide tubular structures into compartmental cells.
The following are some of the organelles present in these cells:
Ribosomes
Nucleus (the cells may be binucleate or multinucleate)
Globules
Vacuoles
Mitochondria
The plasma membrane surrounds each cell, which is in turn surrounded by the cell wall. As the mycelia begin to expand and branch, this strengthens them.
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Modifications of Mycelium Fungi
The majority of fungi have basic hyphae.
In some advanced fungi, hyphae may change in response to functional requirements.
Hyphal modifications are hyphal aggregations that are necessary during the life cycle of fungi to perform specific functions.
In fungi, important hyphal modifications include:
1. Prosenchyma:
Fungi type prosenchyma, which is made up of loosely packed tissue.
When the component hyphae are arranged more or less parallel to one another, prosenchyma is formed, and the entire mass becomes a felt-like structure.
The hyphae join together to create a loosely woven frame.
The uniqueness of fungal hyphae is preserved in prosenchyma.
Plectenchyma or Proso-plectenchyma are other names for Prosenchyma.
2. Pseudo-Parenchyma:
In cross-section, the hyphae are tightly entangled and form a tissue-like structure.
The hyphae lose their identity and are no longer distinguishable from one another in pseudo-parenchyma.
In cross-section, pseudo-parenchyma resembles the parenchymatous tissue of higher plants.
Para-plectenchyma is another name for them.
3. Rhizomorphs
In certain fungi, rhizomorphs are thick strands or root-like aggregations of somatic hyphae.
Mycelial cords is another name for them.
They're gelatinous, dark brown, and have coiled structures that look like rope.
The intertwining of hyphae in rhizomorphs is too close, causing hyphae to lose their individuality.
Individual hyphae are aligned in a parallel pattern.
Individual hyphae have a lower infection potential than Rhizomorphs.
They're perennating systems with a lot of penetration power.
Rhizomorphs can live for several years and, in the right conditions, can produce new mycelia.
4. Sclerotium
In certain fungi, sclerotia is a compact globose structure produced by the aggregation of hyphae.
The interwoven hyphae are extremely compact, and the individuality of the hyphae is lost, resulting in rounded, cushion-like structures.
Sclerotia will live for a long time, sometimes even years.
They are the dormant stage of some fungi.
They aid in vegetative reproduction by accumulating food materials.
The outer cells of sclerotia turn a dark brown colour, while the inner cells remain colourless.
5. Appressorium
Appressorium is a terminal simple or lobed swollen structure of germ tubes on infecting hyphae
Appressorium is found on many parasitic fungi such as rusts and powdery mildews
It adheres to the surface of the host and helps in the penetration of hyphae
The infection peg is originated from the appressorium
6. Haustorium
Haustoria are obligate parasites' intracellular absorption structures.
They're designed to absorb food particles from the host tissue.
Haustoria come in a variety of sizes and shapes.
Knob-like, elongated, finger-like, or branched shapes are possible.
They secrete enzymes that aid in the hydrolysis of the host's proteins and carbohydrates.
7. Stroma
Stroma are somatic structures that are compact.
They're pseudoparenchymatous structures that look like flat cushions.
They normally have fructifications on or in them.
8. Snares
Predaceous fungi create snares, which are trap-like structures that capture small organisms like nematodes and protozoans.
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Mycelium Functions
Mycelium plays an important role in the decomposition of various complex organic compounds since they expand and spread widely. Biomass is converted to compost in this way.
Because of their symbiotic relationship with plants, they can increase crop yields.
They have the potential to ruin food.
As the mycelium continues to expand and spread within or on the surface of the substrate, it absorbs nutrients, which are then transferred to the fruiting bodies to promote growth and reproduction.
They are also involved in reproduction.
Mycelium Reproduction
When a spore germinates to form homokaryotic mycelia, mycelia are involved in reproduction. The homokaryotic, also known as homokaryon, are mycelia with nuclei of the same genotype.
As spores like basidiospore germinate, they produce homokaryotic mycelium, which is made up of monokaryon or uninucleate cells. The hyphal walls crack open when two monokaryons come into contact, a phenomenon known as hyphal anastomosis. This allows the nuclei of vegetatively compatible monokaryons to pass into the other monokaryon's mycelia.
Finally, the formation of binucleate cells and, as a result, the formation of dikaryon mycelium occurs. The dikaryotic mycelium can produce fruiting bodies that are involved in sexual reproduction depending on external conditions (moisture, temperature, and pH, among others).
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Difference Between Mycelia and Hyphae
Though fungal hypha is increasingly branching to form mycelium, mycelium is made up of hyphal threads, which are the vegetative component of fungi.
The mycelia are the fungi's bodies, while the hyphae are the fungi's building blocks.
Mycelia are densely branched and thick, while hyphae are not.
Some hyphae can be seen with the naked eye, but not all mycelia.
Similarity Between Mycelia and Hyphae
Decomposition of substrates is aided by both hyphae and mycelium.
FAQs on What Is Mycelium? Structure, Functions & Role in Nature
1. What is mycelium in the context of Kingdom Fungi?
In the study of fungi, the mycelium is the main vegetative part of the organism. It is a vast, interconnected network of thread-like filaments called hyphae. This network typically grows underground or within a substrate, such as soil or wood, and is responsible for absorbing nutrients.
2. What are hyphae, and how do they form the mycelium?
Hyphae are the long, branching, filamentous structures that are the basic building blocks of a fungus. Each hypha is a tube-like cell containing cytoplasm, enclosed by a cell wall primarily made of chitin. As these individual hyphae grow and branch out extensively, they interweave to form a dense, complex mass known as the mycelium.
3. How does mycelium obtain nutrition?
Mycelium obtains nutrition through a process called absorptive heterotrophy. It secretes powerful extracellular enzymes directly into its surrounding environment. These enzymes break down complex organic matter—like dead leaves, wood, or other organisms—into simpler, soluble molecules. The mycelium then absorbs these small molecules through its vast surface area to fuel its growth.
4. What is the difference between septate and aseptate (coenocytic) mycelium?
The key difference lies in the internal structure of the hyphae, which is a significant feature in fungal classification as per the CBSE syllabus:
- Septate Mycelium: The hyphae are divided by internal cross-walls called septa. These septa have small pores that allow cytoplasm and organelles to move between adjacent cells. This type is characteristic of higher fungi like Ascomycetes and Basidiomycetes.
- Aseptate (Coenocytic) Mycelium: The hyphae lack septa and exist as a single, continuous, elongated cell with multiple nuclei. This structure results from nuclear division without cell division and is found in lower fungi like Phycomycetes.
5. How does mycelium differ from a fungal spore?
Mycelium and spores represent two different stages in the fungal life cycle with distinct functions:
- Mycelium: This is the vegetative, growing, and feeding part of the fungus. It is a large, multicellular network responsible for colonising a substrate and absorbing nutrients.
- Spore: This is a small, typically single-celled reproductive unit. It is metabolically dormant and built for dispersal and survival in harsh conditions. When a spore lands in a suitable environment, it germinates to form a new mycelium.
6. What is the functional difference between mycelium and mycorrhizae?
While related, these terms are not interchangeable. Mycelium is the general term for the body of a fungus. Mycorrhizae, on the other hand, refers to a specific, symbiotic association between a plant's root system and the mycelium of a fungus. In this relationship, the mycelium extends far into the soil, providing the plant with essential nutrients like phosphorus, while the plant provides the fungus with sugars produced through photosynthesis.
7. What are some important applications of mycelium in technology and ecology?
Mycelium has numerous significant applications beyond its natural role, including:
- Ecology: It is fundamental to decomposition and nutrient cycling, breaking down organic matter and making nutrients available in ecosystems.
- Biomaterials: It is cultivated to create sustainable and biodegradable materials used as alternatives to leather, plastic packaging, and insulation.
- Medicine: Fungal mycelia are the source of critical medicines, most famously antibiotics like penicillin.
- Food Industry: It forms the structure of edible mushrooms and is used in the fermentation of various food products.
8. How does the vast underground mycelial network contribute to the ecosystem?
The mycelial network functions as a critical infrastructure for terrestrial ecosystems. Its primary role is as a master decomposer, breaking down tough organic materials like lignin and cellulose, which releases vital nutrients back into the soil for plants to use. Furthermore, through mycorrhizal associations, it connects different plants, even of different species, forming an underground system sometimes called the 'Wood Wide Web'. This network can transport water, carbon, and other nutrients between connected plants, enhancing the resilience and health of the entire forest.
