Mycorrhiza: Meaning and Types of Mycorrhiza (With Diagram) | Mycology

In this article we will discuss about (1) Meaning of Mycorrhiza (2) Types of Mycorrhiza

(1) Meaning of Mycorrhiza

• Mycorrhiza is the symbiotic relationship between roots of higher plants (Seed plant) and fungus.
• Mycorrhiza is an example of symbiosis. Fungus obtain food and shelter from root and it helps to root in absorption of water & minerals.
• Mycorrhiza name was given by "Frank" (1885).

(2) Types of Mycorrhiza

(a)  Ectomycorrhiza

• In this type of mycorrhiza surface of root completely covered by pseudo parenchymatous sheath formed by fungal hyphae.
• Fungal hyphae enter intercellulary in cortical cell of root.
• Fungal hyphae which arises from pseudo parenchymatous sheath limited up to outer cortical cell and form a net called "Hartig net".
• Ectomycorrhiza occurs in Pinus, Fagus, Abies, Oak, Eucalyptus etc.
• Fungus mainly members of class basidiomycetes. eg. Clavatia, Amanita, etc.
• Root hair are absent on root.
• Fungus helpful in absorption of water and minerals.
• Due to presence of fungus absorptive surface of root increses. In return fungus gets carbohydrates from the root.

Note : Amanita is found in Pinus roots where as Russula is found in Fagus roots.

(b)  Endomycorrhiza :

• In this type of mycorrhiza fungus does not form pseudo parenchymatous sheath.
• Some fungal hyphae enter intracellularly in cortical cells of root. Intracellular fungal hyphae form unranched knob like structures called asvesicle, and form branched tree like structures  in cortical cells, called"arbuscule".
• So the endomycorrhiza is called Vesicular arbuscular mycorrhiza (VAM).
• VAM is useful for phosphate nutrition.
• Endomycorrhiza occurs in orchids.
• Endomycorrhizal fungi are mainly member of class "zygomycetes". Ex. Corticium, Rhizoctonia etc.
• Mycorrhiza is an example of symbiosis. Fungus obtain food and shelter from root and it helps to root in absorption of water & minerals.

Note :-

1. Armillaria fungi mainly found in orchid's roots.  

2. (A) Ectomycorrhizal genera ® Hebeloma, Laccaria, Pisolithus

(B) Endomycorrhizal genera : Glomus, Gigaspora, Sclerocystis.

 3. Arbuscule acts as a haustorium.

4. Orchids are obligately dependent on mycorrhizal association for seed germination & further development.

5. Endomycorrhiza occur in about 80% of all vascular plants.

Example :

Indian pipe plant (Monotropa indica)

It belongs to family - Ericaceae

Note : Ectendotrophic mycorrhiza : Mycorrhiza sharing characteristics of both ecto and endo mycorrhizae are called ectendotrophic mycorrhiza.