Mycorrhizal Fungi

Arbuscular Mycorrhizal Fungi (AMF)

• 1

  Ubiquitous

  More than 80% of land plants are mycorrhized by AMF to improve their nutrition and resilience to stress.

• 2

  Sensitive

  Sensitive to soil disturbance (tillage, pesticides), AMF are the barometer of soil health.

• 3

  Abundant

  AMF represent 20 to 30% of soil microbial biomass and produce a very dense network of filaments that can reach up to 100m of filaments/cm³ of soil.

• 4

  Diverse

  Nearly 400 identified species, the only microorganisms covering all 6 soil functions (regulation of water and contaminant cycles, nutrient supply, carbon storage, biodiversity support, soil structure maintenance).

In the soil

Mycorrhizal fungi form a very dense network of filaments: the mycelium. This mycelial network enables:

• 1

  Multiplication by up to 1,000 of the soil volume explored by roots.

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  Increased microbial activity and stimulation of microflora competing with pathogens.

• 3

  Improved soil structure (glomalin production, carbon sequestration) and reduced erosion.

• 4

  Regulation of toxic molecules (salt, heavy metals, hydrocarbons) by sequestration in the mycelium and spores.

In the roots

AMF draw water and nutrients in exchange for sugars from plant photosynthesis. The exchange takes place at the level of arbuscules, microscopic fungal structures present in root cells. Arbuscules: exchange sites between roots and AMF.

• 1

  Better absorption of water and nutrients.

• 2

  Greater tolerance to stress (water, salt, metal).

• 3

  Better protection against diseases.

Practices impacting mycorrhizal biodiversity

Certain practices negatively affect mycorrhizal abundance and diversity:

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  Pesticides

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  Deep tillage

• 3

  Synthetic fertilizers