Definition: It is the symbiotic association of a fungus with the roots of a higher plants.
It was Frank the German Botanist who discovered it in 1885. The fungus that enters in this symbiotic association is called mycorrhizal fungus.
Usually the fungus associates with the roots of higher plants and thus mycorrhizal association plays a significant role for the proper absorption of minerals by the root system and thus influences the general growth of higher plants.
Mycorrhizal formation: When the roots of higher plants become infected with fungi, the plant root gets modified to accommodate the fungus.
Mycorrhizal association are not specific i.e., fungus can associate with many plants and a plant can accommodate many fungi..
It is symbiotic association. Fungus lives on sugars provided by the plant cells. The growth of the fungus does not damage the plant cells. The fungus helps the plant to absorb water and minerals from the soil. Plant with mycorrhizal association can absorb two to three times more minerals like nitrogen, phosphorus and potassium
Fungus can produce various growth promoting substances and antimicrobial substances.
Mycorrhizae are found in pines, birches and orchids. Pines and birches show stunted growth if mycorrhiza are absent. Many orchids cannot live without mycorrhizae and their seedling grow only when root become associated with it .
Classification of Mycorrhiza
On the basis of morphology and anatomy, mycorrhizae are classified into three groups namely