Factsheet S18: Mycorrhizas

Mycorrhizas are specialised structures which develop where certain fungi colonise the tissues of fine roots. The fungi help in the mineral nutrition of the plant in return for carbohydrates and other substances such as vitamins. This mutually beneficial relationship is called symbiotic or a symbiosis.
It has become evident over the last 20 years than most woody species, and many perennials and annuals as well (eg. cereals, grasses, clovers), not only form mycrorrhizal relationships with various species of fungi, but sometimes depend on them for healthy growth and survival. Some orchids and pines, for example, cannot grow normally without specific mycorrhizal fungi.