Micorriza

Micorriza, known in English as mycorrhiza, is a symbiotic association between a fungus and a plant root. In this partnership, the fungus colonizes the root surface or interior and extends hyphae into the surrounding soil. The relationship is mutualistic: plants supply sugars to the fungus, while the fungus increases the plant’s access to water and nutrients, especially phosphorus and micronutrients, and can improve soil structure.

Two major forms are ectomycorrhiza (ECM) and arbuscular mycorrhiza (AM), also called vesicular-arbuscular mycorrhiza. Ectomycorrhizal fungi form a sheath around root tips and a Hartig net between root cells, typically associating with woody plants such as pines, oaks, and birches. Arbuscular mycorrhizal fungi penetrate cortical cells to form arbuscules and vesicles, a common arrangement for most herbaceous plants and many crops.

Functions and benefits include expanded nutrient uptake and water absorption due to the extensive fungal hyphae, enhanced phosphorus acquisition, and improved soil aggregation. In return, plants provide carbohydrates to the fungus. Mycorrhizae can also influence plant resistance to certain soil-borne pathogens and help establish plants in poor or disturbed soils. They are widespread in terrestrial ecosystems and are especially important for forest trees and many agricultural crops. In agriculture, mycorrhizal inoculants are used to promote growth under suboptimal soil conditions, though the benefits vary with species, soil, and management practices.