What is Ectomycorrhiza and Endomycorrhiza?: Introduction
The word mycorrhiza derives from the Greek “mykes”, meaning fungus and “rhiza”, referring to roots. Thus, it refers to a symbiotic association between plants and fungi, that is, both the plant and fungi in this type of association is benefitted. Usually, this symbiosis is between green chlorophyllous plants that are autotrophs and produce their food and nutrients through photosynthesis.
Hence, these plants can provide the necessary nutrients that the fungi in this association require. In return, the fungi interacting with the roots of these plants help them absorb soil water and minerals, especially phosphorus, nitrogen and others. These also protect the plant roots from the invasion of other microbes and increase their efficiency for absorption, thereby improving the survivability of the plants even in limited soil conditions. Mycorrhiza are two kinds, namely ectomycorrhiza and endomycorrhiza. The ectomycorrhizal association is when the fungi do not penetrate the plant roots, whereas endomycorrhiza refers to an association involving fungal penetration of the plant root cortex.
Characteristics of Ectomycorrhiza and Endomycorrhiza
To understand ectomycorrhiza and endomycorrhiza difference, it is important to know what their characteristics are.
Ectomycorrhiza: In ectomycorrhizal association, the fungal hyphae do not penetrate the cortical cell wall of the plant root. Rather they form a network of hyphae that penetrate between the root epidermis and cortex, known as the Hartig net. This structure provides the plants with the necessary minerals and allows the exchange of nutrients between the two. Apart from the Hartig net, the fungi also form a meshwork of hyphae which is comparatively denser and ensheaths the plant root tip. Woody plants are mostly involved in an ectomycorrhizal association with fungi belonging to the class Ascomycetes, Zygomycetes and Basidiomycetes.
Endomycorrhiza: In endomycorrhizal association, the fungal hyphae penetrate the plant cell wall.
Arbuscular mycorrhiza: In the most common type of endomycorrhizal association, that is in arbuscular mycorrhiza, the hyphae do not enter the cell cytoplasm, rather it causes the membrane to invaginate. At this contact site, the surface area is made to increase by the formation of structures called vesicles and arbuscules. These morphologies allow better nutrient exchange between the two.
Ericoid Mycorrhiza: In Ericoid mycorrhizal association, the hyphae form a loose network around the root hair and penetrate the cortical cell wall.
Differences Between Ectomycorrhiza and Endomycorrhiza
It is a mutualistic association between plants and fungi where the fungal hyphae do not penetrate the plant root cell instead, it extends in between the cells.
It is a mutualistic association between plants and fungi where the fungal hyphae penetrate the host cell wall.
Location of association
The ectomycorrhizal association is extracellular.
The endomycorrhizal association is intracellular.
The structures involved in an ectomycorrhizal association are the mantle and Hartig’s net.
The most common type of structures observed in an endomycorrhizal association are arbuscules and vesicles.
Arbutoid mycorrhizal associations fall under the category of ectomycorrhiza. Ectomycorhhiza also forms a kind of symbiotic association with the arbuscular mycorrhiza and is termed ectendomycorrhiza.
Endomycorrhiza is of several types, like arbuscular, Ericoid, Orchid and Monotropoid Mycorrhiza.
Fungi group associated with the mutualism
The phylums Ascomycota, Basidiomycota and Zygomycota form ectomycorrhizal interaction with the roots of woody trees.
The phylum Glomeromycota forms an arbuscular mycorrhizal association with vascular plants. However, Basidiomycetes are known to form Orchid Mycorrhiza.
Ectomycorrhiza constitutes only 4% of the mycorrhizal population and is thus scarce compared to the endomycorrhizal population.
Endomycorrhizal constitutes about 80% of the mycorrhizal population and is thus more abundant than ectomycorrhiza.
To summarize, this article sheds light on the differences between the two types of mycorrhizal association, ectomycorrhiza and endomycorrhiza. It also explains what these terminologies mean, their characteristics and the structures associated with the formation of this kind of symbiosis. Though there are some stark differences between them, the ultimate significance of the two is the same, that is, they assist in nutrient exchange between the plants and the fungi.
FAQs on Difference Between Ectomycorrhiza and Endomycorrhiza
1. What is the main difference between ectomycorrhiza and endomycorrhiza?
The predominant difference between ectomycorrhiza and endomycorrhiza is that the former is extracellular and does not penetrate through the plant cell wall, whereas the latter does and is intracellular. Ectomycorrhiza forms structures like Hartig's net and the mantle where the hyphal network surrounds the root tip without inserting itself through the cortical cell wall. In endomycorrhiza, structures like the arbuscules and vesicles form at the contact site between the fungal hyphae and the plant cell membrane.
2. What are some examples of ectomycorhhiza and endomycorrhiza?
Ectomycorrhizal association takes place between woody trees, which may be both coniferous or non-coniferous, for instance, birch, oak, pine, willow and others and the fungal phylum Ascomycota, Basidiomycota and Zygomycota. Examples of the fungal species are Amanita spp., Tricholoma spp. and others. However, only the Pinaceae family exhibits an ectendomycorrhizal association.
The endomycorrhizal association is usually observed in vascular plants. For example, the Arbuscular mycorrhizal association occurs between the fungal phylum Glomeromycota and many crop plants. Ericoid mycorrhizal association occurs between Ascomycota fungal members and plant groups like Erica and Vaccinium. The Orchid mycorrhizal association is between Orchidaceae and Rhizoctonia, a Basidiomycetes.
3. What is the significance of mycorrhizal association?
The mycorrhizal association is a mutualistic arrangement between plants and fungi. The autotrophic plant provides the fungi with sugar sources, whereas the fungi help the plant absorb soil water and minerals. Though ectomycorrhiza and endomycorrhiza exhibit varied morphology, like Hartig’s net and mantle in the case of the former and vesicles and arbuscules for the latter, all these networked structures aim at increasing the surface area of contact between the plant root cells and the hyphae. Such an arrangement allows better nutrient exchange between the two. The fungi are also known to protect the plants from any other invading microbes.