Mycorrhiza, from the Greek myco meaning "fungus" and rhiza meaning "root", is the result of a perfect symbiosis between fungi and plants. The filamentous vegetative structure formed by many fungi or bacteria is called the mycelium. These two organisms maintain a reciprocal symbiotic relationship, each providing essential benefits to the other for survival.
The fungus enhances the plant’s ability to absorb vital soil minerals such as phosphorus and nitrogen by expanding the root's surface area. Additionally, it increases resistance to root diseases. In return, the plant provides fungi with carbohydrates necessary for their survival without competing with other microorganisms in the soil. This mutual exchange ensures protection and sustenance for both organisms, maintaining their symbiotic relationship in perfect harmony.
In total, mycorrhizae make up approximately 25% of the world’s soil bacterial biomass.
Types of Mycorrhizae
There are several types of mycorrhizae, but two main groups stand out: ectomycorrhizae and endomycorrhizae.
Ectomycorrhizae exist outside plant cells, forming a sheath around the root that significantly expands the plant's root system. Fine filaments emerge from this sheath, penetrating between cells but never inside them. This type of symbiosis is found in various Canadian species such as pine, willow, oak, and birch. Ectomycorrhizae are common in Canadian forests, particularly during rainy seasons, when fungi can reproduce more easily. These fungi facilitate the assimilation of nitrogen, especially in its complex forms, though they compete with other microorganisms for nutrients from decomposing leaves.
Endomycorrhizae are distinguished by their ability to penetrate directly into plant cells, enabling a more efficient exchange of nutrients and fostering a stronger bond between the plant and fungus. Approximately 80% of plant species maintain this relationship with endomycorrhizal fungi.
Benefits of Mycorrhizae for Plants
- Significantly extends the root system
- Fungi extract water and nutrients over a larger area, increasing nutrient availability for plants
- Enhances plant growth
- Facilitates resource sharing between plants
- Improves soil stability by acting as an essential support throughout the plant’s lifespan
- Increases disease resistance
- Strengthens soil anchoring, improving seedling and transplant survival
- Boosts plant tolerance to water and salt stress
- Maintains the balance of nutrient cycles and soil quality
- Enhances flowering and fruit production
- Stimulates microbial activity
- Reduces or eliminates the need for fertilizers
Overall, mycorrhizal fungi improve plant health and make them more resilient.
Benefits for Soil Structure
- Promotes better root development
- Enhances microbial activity
- Increases water retention and infiltration capacity
- Improves soil aeration
- Reduces and controls soil erosion
- Strengthens resistance to soil compaction
Recognizing these numerous benefits, we can confidently say that mycorrhizae are an effective tool for maintaining plant health. Incorporating mycorrhizae into your future plantings will allow you to witness the remarkable effects of this symbiosis: healthier, stronger, and more resistant plants!
Souces
Raven, P.H., R.F. Evert et S.E. Eichhorn 2014. Biologie végétale. 3ième édition. Traduction de la 8ième édition américaine. de boeck.
http://www.mykepro.com/mycorhizes-benefices-application-et-recherche.aspx