Mykorrhizan

Mykorrhizan is the symbiotic association between a plant root and a fungus, forming what is commonly called a mycorrhiza. In this partnership, fungal hyphae colonize the root and extend the plant’s effective root surface, improving nutrient uptake. The term comes from Greek mykes (fungus) and rhiza (root).

Two major forms occur in most ecosystems: ectomycorrhiza, where a fungal mantle covers the root tip and a Hartig net develops between root cells (common in trees); and arbuscular mycorrhiza (or arbuscular endomycorrhiza), where fungi penetrate cortical cells and form arbuscules (widespread in herbaceous plants and crops). Other types include ericoid and orchid mycorrhizas.

Functionally, Mykorrhizan enhances nutrient and water uptake. Fungal partners supply phosphorus, micronutrients, and sometimes nitrogen, while plants provide carbohydrates. The association can boost growth, drought tolerance, and disease resistance and can improve soil structure through hyphal networks and hyphal exudates.

Ecologically, most land plants form mycorrhizas, making these associations central to nutrient cycling and plant community dynamics. Mycorrhizal networks can connect neighboring plants, enabling transfer of carbon, water, or signaling compounds, and influencing ecosystem productivity and resilience.

In agriculture and forestry, mycorrhizal inoculants are used to improve establishment and tolerance to stresses, particularly on low-phosphorus soils. Effectiveness depends on plant-fungus compatibility, soil conditions, and management. Introducing non-native fungi can disrupt native communities, so application is guided by ecological risk considerations.