Exploring Mycorrhizae

About Mycorrhizae

Mycorrhizae are symbiotic relationships that form between fungi and plants. The term "mycorrhiza" comes from the Greek words for "fungus" and "root," which accurately describes this relationship. The fungi colonize the root system of a host plant, providing increased water and nutrient absorption capabilities while the plant provides the fungus with carbohydrates formed from photosynthesis. This mutually beneficial relationship is an important part of soil life and plant health.

There are several types of mycorrhizal associations, but the two most common types are ectomycorrhizae and endomycorrhizae (or arbuscular mycorrhizae).

  1. Ectomycorrhizae: This type of mycorrhiza forms a sheath, or mantle, around the root tips of the host plant. The fungal hyphae also penetrate the root tissue, but do not penetrate individual cells within the root. Ectomycorrhizae are common in many forest trees, including pines, oaks, spruces, and firs.

  2. Endomycorrhizae (Arbuscular Mycorrhizae): In this type of mycorrhiza, the fungal hyphae penetrate the walls of root cells and form branched structures known as arbuscules, which are involved in nutrient exchange between the fungus and the host plant. Arbuscular mycorrhizae are found in a wide range of plants, including grasses, crops like maize and tomatoes, and many wild and ornamental plants.

Benefits of Mycorrhizae

Mycorrhizae have several benefits for their host plants:

  • Nutrient Acquisition: Mycorrhizal fungi are very efficient at absorbing nutrients from the soil, especially phosphorus and nitrogen, and can transfer these nutrients to the plant. The hyphae of the fungi can access small soil pores that plant roots cannot reach, increasing the plant's access to soil nutrients.

  • Water Uptake: The extensive network of fungal hyphae also increases the plant's ability to absorb water, enhancing its drought tolerance.

  • Disease and Pest Resistance: Some mycorrhizal fungi can protect plants from root diseases and pests by competing with or actively suppressing disease organisms.

  • Soil Structure: The hyphae and other structures produced by mycorrhizal fungi can help bind soil particles together, improving soil structure and preventing erosion.

In agriculture and horticulture, mycorrhizal fungi are often added to the soil as "inoculants" to boost plant health and productivity. However, they're also an important part of natural ecosystems and play a crucial role in soil fertility and plant diversity.

Mycorrhizal Networks

In some cases, the hyphae of mycorrhizal fungi can connect the root systems of different plants, forming a "mycorrhizal network" or "common mycorrhizal network." These networks can facilitate nutrient and water movement between plants and may also play a role in plant communication.

Mycorrhizae and Climate Change

Mycorrhizae may also have an impact on climate change. The fungi play a significant role in soil carbon storage, as they convert plant-derived carbon into soil organic matter. Additionally, by enhancing plant health and growth, mycorrhizae can contribute to increased carbon sequestration by plants. However, changes in climate and land use can affect mycorrhizal communities and their functioning, with potential consequences for the global carbon cycle.