In a mycorrhizal association, what do fungi obtain from plant roots?

• A. Sugars from the plant
• B. Water from the soil
• C. Atmospheric nitrogen
• D. Oxygen

Answer: (A)

Fungi in a mycorrhizal partnership receive carbon in the form of sugars from the plant. Plants produce sugars by photosynthesis and export surplus sugars to the fungal partners, which fuels the fungal hyphae inside the roots and the extended network into the soil. In return, the fungi help the plant absorb nutrients and water from the soil, creating a mutualistic exchange. Water and nutrients come from the soil, not from plant roots to the fungi, and atmospheric nitrogen or oxygen aren’t provided to the fungi by the plant roots in this relationship.