Biology
Mycorrhizae
Quick fact
Over 90% of land plants engage in mycorrhizal partnerships, making this one of the most common and ancient symbioses on Earth.
Why this is interesting
Have you ever wondered how plants get the nutrients they need from the soil? It turns out they have a fungal partner that acts like an underground internet, trading resources in a secret network beneath your feet.
Read the full explanation
Understanding Mycorrhizae
Mycorrhizae are intimate partnerships between plant roots and fungi. In this arrangement, the fungus colonizes the root system, either growing inside root cells (arbuscular mycorrhizae) or wrapping around them (ectomycorrhizae). The fungal threads, called hyphae, extend far beyond the root zone, effectively expanding the plant's reach for water and nutrients, especially phosphorus and nitrogen. In return, the plant supplies the fungus with sugars produced through photosynthesis. This mutual exchange allows both organisms to thrive. The result is a healthier, more resilient plant and a fungus that gains a steady food supply.
A deeper explanation
The mechanism hinges on a finely tuned nutrient exchange. Fungi have enzymes that break down organic matter and access nutrients in soil that plant roots cannot directly absorb, such as phosphorus in insoluble forms. Arbuscular mycorrhizal fungi form tree-like structures called arbuscules inside root cells, providing a large surface area for nutrient transfer. In ectomycorrhizae, the fungus wraps root tips in a dense fungal sheath called a mantle, with hyphae weaving between root cells. Both types create a bidirectional flow: plants export sugars to the fungus, and the fungus delivers soil-derived nutrients. This symbiosis is ancient, dating back over 400 million years, and is essential for plant colonization of land. Mycorrhizae also connect plants into common mycelial networks, allowing resource sharing between individuals. Their role in carbon sequestration, soil structure, and agriculture makes them vital for ecosystem functioning and food security.