Mykorriisayhteyksiä

Mykorriisayhteyksiä, often translated as mycorrhizal associations, refers to the symbiotic relationship between fungi and plant roots. This mutually beneficial interaction is widespread in terrestrial ecosystems, with estimates suggesting that over 90% of plant species engage in some form of mycorrhizal association. The word "mykorriisa" itself is derived from Greek, meaning "fungus root."

In a mycorrhizal association, the fungal hyphae, which are thread-like structures, extend from the plant root into the soil. This significantly increases the surface area available for nutrient and water absorption, allowing the plant to access resources that would otherwise be unavailable. The fungi are particularly adept at acquiring phosphorus and nitrogen from the soil. In return, the plant provides the fungi with carbohydrates, primarily sugars produced during photosynthesis.

There are several types of mycorrhizal associations, with the most common being ectomycorrhizae and endomycorrhizae (also known as arbuscular mycorrhizae). Ectomycorrhizal fungi form a sheath around the root tips and penetrate the spaces between root cells, but not the cells themselves. Endomycorrhizal fungi, on the other hand, penetrate the root cells, forming specialized structures called arbuscules where nutrient exchange occurs.

Mycorrhizal associations play a critical role in plant health, growth, and survival. They enhance drought tolerance, improve resistance to soil-borne pathogens, and can even facilitate communication between plants through the fungal network. This ecological partnership is fundamental to the functioning of most terrestrial plant communities.