Mycorrhizae
Have you ever wondered how plants thrive and access the nutrients they need? Hidden below ground, a fascinating partnership plays a crucial role: the relationship between plant roots and beneficial fungi called mycorrhizae. The term means "fungal root," and these fungi are essential for the health and vigor of most plants.
Mycorrhizae form a symbiotic relationship that benefits both plant and fungus. Plants provide the fungi with sugars and carbon since fungi cannot photosynthesize. In return, mycorrhizae extend the plant's root system, dramatically increasing the absorption of water and crucial nutrients from the soil—particularly phosphorus, nitrogen, and zinc.
The fungi's network of threads, called hyphae, is much finer than plant roots and can explore more soil volume. While a plant's roots occupy only a small portion of topsoil, mycorrhizal fungi reach far beyond, accessing otherwise unavailable nutrients. This is crucial for phosphorus, which often exists in forms that regular roots cannot use. Some mycorrhizae even work with decomposing organisms to extract nutrients from decaying matter.
There are two main classes of mycorrhizae: ectomycorrhizae and endomycorrhizae.
Ectomycorrhizae (or sheathing mycorrhizae) form a mantle around young root ends and grow between—but not inside—root cells. They commonly appear on evergreen and deciduous trees like pine, oak, birch, and willow. Many belong to the Basidiomycetes class, which includes mushrooms.
Endomycorrhizae grow within plant root cells, developing entirely inside the root. The most common type, arbuscular mycorrhizae (AM), appears on most deciduous trees, annual crops, and herbaceous plants. Their hyphae grow both between and within cortical cells, forming specialized structures called haustoria for nutrient exchange.
Beyond nutrient uptake, mycorrhizae offer several other benefits:
Increased pathogen resistance
Enhanced tolerance to drought and salinity stress
Improved transplanting success
Potential for increased crop yield and flowering
Improved soil structure
Soil management practices significantly affect mycorrhizal activity. Excessive fertilization with nitrogen and phosphorus, soil fumigation, and removal of topsoil can reduce their presence and effectiveness. However, adding mulch and compost creates ideal conditions for their growth.
Mycorrhizae are vital yet invisible partners in plant health. When plants show nutrient deficiencies despite good soil fertility, consider whether this fungal partnership needs attention. By supporting these underground allies, we create stronger, more resilient plants.
