Mycorrhiza

Arbuscular mycorrhiza seen under microscope. Arbuscular mycorrhiza are those where the fungus penetrates the outer layer of the cells of the roots of a plant, in this case flax.

Topic in Gardening courses

A mycorrhiza is a symbiotic (generally mutualistic, but occasionally weakly pathogenic) association between a fungus and the roots of a higher plant. In a mycorrhizal association, the fungus colonizes the host plant's roots, either intracellularly or extracellularly. They are an important component of soil life.

Definitions of mycorrhiza

• "Mycorrhizas are symbiotic associations essential for one or both partners, between a fungus (specialised for life in soils and plants) and a root (or other substrate-contacting organ) of a living plant, that is primarily responsible for nutrient transfer. Mycorrhizas occur in a specialised plant organ where intimate contact results from synchronised plant-fungus development."
• "A mycorrhiza is a symbiotic (generally mutualistic, but occasionally weakly pathogenic) association between a fungus and the roots of a vascular plant. In a mycorrhizal association, the fungus colonizes the host plant's roots, either intracellularly as in arbuscular mycorrhizal fungi (AMF), or extracellularly as in ectomycorrhizal fungi. They are an important component of soil life and soil chemistry.
• "The symbiotic association of the mycelium of a fungus with the roots of a seed plant"

How many plants form mycorrhiza

• "While it is clear that the majority of plants form mycorrhizas, the exact percentage is uncertain, but it is likely to lie somewhere between 80% and 90%. In many of these associations between 10% and 30% of the food produced by the plant moves through to the fungi."

The length of roots and extended hyphens

• Do you know how long all the root segments of the entire root system of a single rye plant can become? According to Brian Capon in his book 'Botany for gardeners' it was once measured. The figure is unbelievable: 380 miles or 630 km.

Types of mycorrhiza

Endomycorrhiza

Wheat is an example of endomycorrhizal plant

They are the most abundant type of mycorrhiza and the most ancient. It is likely that these fungi originated between 350 and 450 million years ago and probably played an essential role in the colonization of land by the plants.

Ectomycorrhiza

Leccinum aurantiacum or red-capped scaber stalk is an example of an ectomycorrhizal fungus

Ectomycorrhizasare typically formed between the roots of around 10% of plant families, mostly woody plants including for example the birch, eucalyptus, oak, pine, and rose families and certain types of fungi. Some of these fungiare symbiotic with only one particular genus of plant, while other form mycorrhizas with many different plants. An individual tree may have 15 or more different fungal ectomycorrhizal partners at one time. Thousands of ectomycorrhizal fungal species exist.

The hyphae of ectomycorrhizal fungi form a mantle around the root and also grow into the spaces between root cells - but do not penetrate the root cells. The hyphae form a net-like covering, called a Hartig net, around the cells.

Ericoid mycorrhiza

Ericoid mycorrhiza are a symbiotic relationship between fungi and the roots of plants from the order Ericales (for example tea, blueberry, azalea).

See also

• Research page:Mycorrhiza

External links

• An online textbook to provide current information about mycorrhizal associations
• International Mycorrhiza Society
• Mycorrhiza Literature Exchange "Posted here are the abstracts of almost all journal articles dealing with mycorrhizae from 1991 through 2009 (over 11,000 citations), as well as citations to some 260 mycorrhizal reviews, over 70 mycorrhizal books, many mycorrhizal theses and dissertations. Also included is almost every article ever published dealing with water relations and mycorrhizae".
• SpringerLink: Online magazine about mycorrhiza

Videos

• Arbuscular mycorrhiza A collection of videos in the Mashpedia Life Encyclopedia.
• "Ever wonder how mycorrhizal fungi improve plant nutrition? This video shows how mycorrhizal hyphae access, unlock and transport soil nutrients."
  
  
• "Michael Melendrez talks about the role of Mycorrhiza: endo/ecto." Part of the content: Grass roots of any kinds of grass grow with many mycorrhiza, which is why lawns and grass land still keeps much of their fertility despite otherwise wrong agricultural methods.