Arbuscular mycorrhizal fungi (AMF)

Definition

Arbuscular mycorrhizal fungi (AMF) are a group of beneficial fungi that form symbiotic relationships with the roots of most terrestrial plants. These fungi enhance nutrient uptake, particularly phosphorus, while the plant provides carbohydrates and other organic compounds to the fungi, creating a mutually beneficial exchange that supports plant health and growth.

5 Must Know Facts For Your Next Test

1. AMF can significantly increase a plant's root surface area, allowing for better absorption of water and essential nutrients.
2. These fungi also improve soil structure and promote soil health by enhancing aggregation and microbial diversity.
3. AMF are crucial in helping plants withstand drought stress by improving water uptake during dry conditions.
4. The relationship between AMF and plants can influence ecosystem dynamics, such as nutrient cycling and plant community composition.
5. Research has shown that AMF can also enhance plant resistance to pathogens by strengthening the plant's immune response.

Review Questions

• How do arbuscular mycorrhizal fungi enhance nutrient uptake in plants?
  • Arbuscular mycorrhizal fungi enhance nutrient uptake in plants primarily by increasing the surface area of the root system. The fungal hyphae extend into the soil, exploring a larger volume than the roots alone could reach. This allows AMF to access nutrients like phosphorus that may be unavailable to plant roots directly. The fungi then transfer these nutrients to the plant in exchange for carbohydrates produced during photosynthesis.
• Discuss the role of arbuscular mycorrhizal fungi in promoting plant health under drought conditions.
  • Arbuscular mycorrhizal fungi play a critical role in promoting plant health during drought conditions by enhancing water uptake capabilities. The extensive network of fungal hyphae helps plants access moisture from deeper soil layers that would otherwise be unreachable. This adaptation not only helps plants survive prolonged dry spells but also supports their overall growth and productivity by maintaining hydration levels even when surface water is limited.
• Evaluate the ecological implications of arbuscular mycorrhizal fungi on nutrient cycling and plant community dynamics.
  • Arbuscular mycorrhizal fungi have significant ecological implications for nutrient cycling and plant community dynamics. By facilitating improved nutrient uptake for various plants, AMF contribute to increased primary productivity and enhance soil health. This symbiotic relationship influences species interactions within communities, as plants with access to AMF often outcompete those without. Consequently, AMF can shape biodiversity patterns by affecting which species thrive in specific environments, ultimately impacting ecosystem resilience and functionality.

Related terms

Ectomycorrhizal fungi: A type of mycorrhizal fungus that forms associations with the roots of certain trees, characterized by a thick hyphal sheath and the formation of a mantle around the root.

Rhizosphere: The region of soil surrounding plant roots where interactions between plants, microbes, and soil occur, playing a crucial role in nutrient uptake and plant health.

Symbiosis: A close and long-term biological interaction between two different biological species, which can be mutualistic, commensal, or parasitic.