Root Directory
Mycorrhizae means Fungus Root. A Mycorrhizae consists of a root and an associated fungus whaich have a symbiotic relationship.
There are two general types of Mycorrhizae, Endomycorrhizae & Ectomycorrhizae.
Endomycorrhizae have fungal hyphae inside cortical cells of roots. They produce characteristic Vesicles (globular structures) and Arbuscules (highly branched structures) inside the walls of cortical cells. Consequently, they are often called Vesicular Arbuscular Mycorrhizae. Internal hyphae are continuous with hyphae on the root surface and in the soil.
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| Images of Endomycorrhizae: Note the presence of Fungal Hyphae in the Cortical Cells of the root. | |||
| Whole Mount of a Root with Endomycorrhizal Fungus: Note the prominent Blue Vesicles in the Cortex. |  |
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Ectomycorrhizae form a thick hyphal mat that surrounds the root. Hyphae penetrate the Root Cortex and have an extensive network therein. The hyphal network in the Cortex is often called the "Hartig Net".
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| Images of Ectomycorrhizae in Root cross-sections: Note the presence of the thick Fungal Sheath (Mantle) that surrounds the root. Hyphae penetrate the Cell Walls of the Cortex where they form the "Hartig Net" but do not enter the protoplasts of these cells. | ||
 Ectomycorrhizal Roots from two Coniferous Trees |
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| Diagram of an Ectomycorrhizal Root: Note the developmental progression of Mycorrhizal roots on the Left-hand picture. The roots infected with Ectomycorrhizal fungi are swollen and branch dichotomously. Note the Fungal Mantle on the outside of the Root and the Hartig Net inside the Cortex. |
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| Comparison
of Ectomycorrhizae (Left) with Endomycorrhizae (Right) |
Mycorrhizae are incredibly important! Over 90% of terrestrial plants have these. They vastly extend the area available for the absorption of water and minerals.
Presence of appropriate fungal partners in nursery soils is critical for the establishment of plants in nature.
This has been widely applied in Forestry BUT is also proving to be important in out-planting native species to re-establish native ecosystems!