Mycorrhizal fungi are ubiquitous in the soil and form symbiotic relationships with the roots of many plants. This mutually beneficial partnership, known as mycorrhiza, plays a crucial role in nutrient absorption and plant growth. This article delves into the mechanisms, benefits, and applications of mycorrhizal fungi, drawing insights from reputable sources such as the University of Wisconsin-Madison, the Royal Horticultural Society, and BBC Gardeners’ World Magazine.
Key Facts
- Symbiotic Relationship: Mycorrhizal fungi form a mutually beneficial relationship with plant roots. The word “mycorrhizal” combines “myco” (fungi) and “rhiza” (root), highlighting the connection between the two.
- Nutrient Absorption: The mycelium of mycorrhizal fungi extends into the soil, forming a network of thread-like strands. This mycelium acts as an extension of the plant roots, greatly increasing the absorption surface area. The fungi absorb nutrients from the soil and transfer them to the host plant.
- Nutrient Exchange: In exchange for nutrients, the plant supplies the mycorrhizal fungi with some of the food it generates through photosynthesis. This symbiotic exchange benefits both parties, as the fungi efficiently “mine” the soil for nutrients and water, while the plant receives enhanced nutrient uptake.
- Extensive Fungal Network: The mycelium of mycorrhizal fungi can cover up to 700 times more soil than the plant roots alone. This extensive network allows the fungi to connect individual plants together, facilitating the sharing of resources in a natural ecosystem. This network is often referred to as the “wood wide web” due to its similarities with the internet.
- Benefits to Plants: Mycorrhizal fungi provide several benefits to plants. They help plants resist drought, produce bigger crops and flowers, resist diseases, and thrive in poor soils or adverse conditions. Woody plants are the primary beneficiaries, but other types of plants also benefit from mycorrhizal associations.
Mechanisms of Mycorrhizal Fungi
Nutrient Absorption:
Mycorrhizal fungi extend their mycelium into the soil, creating a vast network of thread-like strands that significantly increase the absorption surface area of plant roots. This extensive network enables the fungi to access nutrients and water from a larger soil volume, which are then transferred to the host plant.
Nutrient Exchange:
In return for the nutrients acquired from the soil, the plant supplies the mycorrhizal fungi with some of the food it generates through photosynthesis. This symbiotic exchange benefits both parties, as the fungi efficiently extract nutrients from the soil, while the plant receives enhanced nutrient uptake.
Extensive Fungal Network:
The mycelium of mycorrhizal fungi can cover up to 700 times more soil than the plant roots alone. This extensive network allows the fungi to connect individual plants together, facilitating the sharing of resources in a natural ecosystem. This network is often referred to as the “wood wide web” due to its similarities with the internet.
Benefits of Mycorrhizal Fungi to Plants
Drought Resistance:
Mycorrhizal fungi help plants resist drought by increasing their access to water through their extensive mycelium. This enables plants to withstand dry conditions and maintain healthy growth.
Enhanced Nutrient Uptake:
Mycorrhizal fungi improve the plant’s ability to absorb nutrients from the soil, particularly phosphorus, which is often in an insoluble form. This enhanced nutrient uptake leads to improved plant growth and overall health.
Disease Resistance:
Mycorrhizal fungi can provide some protection against soil-borne diseases by acting as a physical barrier and stimulating the plant’s immune system. This helps plants resist diseases and maintain healthy growth.
Tolerance to Adverse Conditions:
Mycorrhizal fungi can help plants tolerate adverse conditions such as salinity, acidity, and high temperatures. This tolerance allows plants to thrive in challenging environments and maintain healthy growth.
Applications of Mycorrhizal Fungi in Gardening
Planting New Plants:
Applying mycorrhizal fungi to the planting hole or directly to the roots of new plants can help them establish more quickly and boost healthy growth. This is particularly beneficial for bare-rooted trees, shrubs, roses, hedging, fruit, and perennials.
Improving Soil Health:
Gardeners can boost natural levels of mycorrhizal fungi by composting, mulching the soil with organic matter, letting leaf litter remain on the soil, and top-dressing with leaf mould. These practices promote a healthy soil environment and support the growth of mycorrhizal fungi.
Container-Grown Plants:
Mycorrhizal fungi can also benefit container-grown plants. When planting container-grown plants, gardeners can mix mycorrhizal fungi into the planting hole or sprinkle it onto the plant roots to ensure immediate contact.
Conclusion
Mycorrhizal fungi form a mutually beneficial relationship with plant roots, known as mycorrhiza. This symbiosis enhances nutrient absorption, improves drought resistance, provides disease protection, and increases tolerance to adverse conditions. Gardeners can harness the benefits of mycorrhizal fungi by applying them to new plants, improving soil health, and using them for container-grown plants. By fostering this symbiotic relationship, gardeners can promote healthy plant growth and maintain a thriving garden.
References:
- Mycorrhizae – Wisconsin Horticulture (https://hort.extension.wisc.edu/articles/mycorrhizae/)
- Complete Guide to Mycorrhizal Fungi | BBC Gardeners World Magazine (https://www.gardenersworld.com/how-to/maintain-the-garden/mycorrhizal-fungi/)
- Mycorrhizal fungi / RHS Gardening (https://www.rhs.org.uk/biodiversity/mycorrhizal-fungi)
FAQs
What is mycorrhizal fungi?
Mycorrhizal fungi are beneficial fungi that form symbiotic relationships with the roots of many plants. This mutually beneficial partnership, known as mycorrhiza, enhances nutrient absorption and plant growth.
How do mycorrhizal fungi benefit plants?
Mycorrhizal fungi provide several benefits to plants, including:
- Improved nutrient absorption, particularly phosphorus
- Enhanced drought resistance
- Increased tolerance to adverse conditions such as salinity, acidity, and high temperatures
- Protection against soil-borne diseases
How do mycorrhizal fungi work?
Mycorrhizal fungi extend their mycelium into the soil, creating a vast network of thread-like strands that significantly increase the absorption surface area of plant roots. This extensive network enables the fungi to access nutrients and water from a larger soil volume, which are then transferred to the host plant. In return, the plant supplies the mycorrhizal fungi with some of the food it generates through photosynthesis.
Can I add mycorrhizal fungi to my garden?
Yes, gardeners can apply mycorrhizal fungi to their gardens to improve soil health and promote plant growth. Mycorrhizal fungi can be applied to the planting hole or directly to the roots of new plants, particularly bare-rooted trees, shrubs, roses, hedging, fruit, and perennials.
How can I encourage the growth of mycorrhizal fungi in my garden?
Gardeners can encourage the growth of mycorrhizal fungi by:
- Composting
- Mulching the soil with organic matter
- Letting leaf litter remain on the soil
- Top-dressing with leaf mould
- Avoiding the use of chemical fertilizers and pesticides
Are there any plants that do not benefit from mycorrhizal fungi?
Yes, plants in the Brassica family, such as broccoli, Brussels sprouts, cabbage, cauliflower, kale, rocket, swede, and turnip, do not benefit from mycorrhizal fungi.
Can I use mycorrhizal fungi with container-grown plants?
Yes, mycorrhizal fungi can also benefit container-grown plants. When planting container-grown plants, gardeners can mix mycorrhizal fungi into the planting hole or sprinkle it onto the plant roots to ensure immediate contact.
Are mycorrhizal fungi safe for the environment?
Yes, mycorrhizal fungi are beneficial to the environment. They play a crucial role in nutrient cycling and help to maintain healthy soil ecosystems.