Types of Mycorrhizae

Types of Mycorrhizae

Types of mycorrhizae
Mycorrhizae are of two kinds:

Ectomycorrhiza Ectomycorrhizal symbiosis is a mutually beneficial union between fungi and the roots of vascular and non-vascular plants. The host of an ecomycorrhizal fungi is usually a gymnosperm (pine). The typical ectomycorrhizal fungi are basidiomycetes (Agaricus), ascomycetes or phycomycetes members. Usuallly more common in the temperate regions, they are capable of growing apart from the host on media containing simple sugars and vitamins. Ectomycorrhizae have poor competitive saprophytic ability hence they have a tough time competing with other microbes in the soil.

During the infection process, ectomycorrhizal fungi in soil are stimulated by the root metabolites to grow toward the root. The hyphae aggregate around the root and penetrate between the root epidermis and the cortex. A structure called Hartig net is formed which is a fungal sheath surrounding the root in which fungal hyphae penetrate between the root cells.

Eventually, the root gets surrounded by a fungal mantle. The fungal hyphae replace the fine lateral root hairs of the host root system thus modifying it structurally. Thus the host root system that is infected with ectomycorrhiza looks stunted and dichotomously branched. The fungal hyphae on the exterior of the roots usually serve as an extension of roots and store large amounts carbohydrates

Endomycorrhiza In this case, the fungal hyphae penetrate the host root cells. They are quite common among the Ericaceae and Orchidaceae members of higher plants as well as fruit trees like citrus, coffee, rubber, etc.

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