Mycorrhiza, a fascinating symbiotic relationship between plant roots and fungi, a widespread and essential component of natural ecosystems, playing a crucial role in the health and functioning of various plant communities. Discovered long ago, this intricate partnership has proven to be beneficial for plant growth, nutrient absorption, and overall ecosystem health.
Mycorrhiza, derived from the Greek words "myco" meaning fungus and "rhiza" meaning root, refers to a mutualistic association between the roots of plants and fungi.
The existence of Mycorrhiza relationships (between plant roots and fungi) was first observed in the mid-19th century by German botanist Albert Bernhard Frank. However, it wasn't until the 20th century that scientists began to understand the significance of these associations in promoting plant health and growth.
Mycorrhiza fungi naturally occur in most soils, forming associations with plants in the wild. Mycorrhiza associations are essential for nutrient uptake by plants, especially phosphorus. The relationship is usually mutualistic - fungi help the plants absorb water and nutrients from the soil, while the plants provide the fungi with sugars produced through photosynthesis.
Some fungi are parasitic, taking products from the plant without providing benefits. Conversely, some mixotrophic or parasitic plants connect with Mycorrhiza fungi as a way to obtain photosynthesis products from other plants.
In nature, Mycorrhiza associations are prevalent, and they contribute to nutrient cycling, plant diversity, and ecosystem resilience. Here are some key aspects of Mycorrhiza in natural environments:
Biodiversity and Plant Succession:
Mycorrhiza associations are integral to the establishment and survival of a wide range of plant species. In natural ecosystems, the presence of Mycorrhiza fungi often facilitates the colonization of plant species in disturbed or nutrient-poor soils. As ecosystems evolve through stages of succession, different Mycorrhiza types may dominate depending on factors like soil conditions, plant species composition, and environmental changes.
2. Nutrient Cycling:
Mycorrhiza fungi enhance nutrient cycling by facilitating the transfer of nutrients, particularly phosphorus, between soil and plants. This contributes to the overall nutrient balance in ecosystems.
The decomposition of organic matter by Mycorrhiza fungi further releases nutrients into the soil, making them available for plant uptake.
3. Disease Resistance and Stress Tolerance:
Mycorrhiza associations can enhance a plant's resistance to soil-borne pathogens. The fungi create a protective barrier and stimulate the plant's defense mechanisms, making it more resilient to diseases. Mycorrhiza symbiosis can also help plants tolerate environmental stressors, such as drought or high salinity, by improving water and nutrient uptake.
4. Forest Ecosystems:
In forest ecosystems, many trees form ectomycorrhizal associations. Fungal hyphae envelop the roots of trees, extending the effective root surface area and aiding in nutrient absorption. The Mycorrhiza network, often referred to as the "wood wide web," allows for interconnecting hyphal networks that facilitate communication and resource exchange between different trees.
5. Symbiotic Relationships with Orchids:
Orchids are known for their unique Mycorrhiza associations. Orchid seeds lack endosperm and depend on specific Mycorrhiza fungi for germination. The fungi provide necessary nutrients to the orchid seed, enabling it to develop into a seedling. Orchids may remain dependent on these fungi throughout their life-cycle.
6. Heathlands and Ericoid Mycorrhiza:
plants in heathlands, such as heathers and blueberries, often form associations with ericoid Mycorrhiza. These fungi help the plants thrive in acidic and nutrient-poor soils characteristic of heathland ecosystems.
7. Plant Communication:
Mycorrhizal networks facilitate communication between plants. Through the exchange of chemical signals and nutrients, plants can respond to environmental stressors or share resources with neighboring plants.
Types of Mycorrhiza
Each type of Mycorrhiza is characterized by the way the fungal hyphae interact with the plant roots. The two main types are endomycorrhizae (also known as arbuscular mycorrhiza) and ectomycorrhizae.
Endomycorrhizae (Arbuscular Mycorrhiza): In endomycorrhizal associations, the fungal hyphae penetrate the plant root cells, forming specialized structures called arbuscules. The most common fungi in endomycorrhizal relationships belong to the Glomeromycota phylum. Endomycorrhizae are found in a wide range of plant species, including many agricultural crops, grasses, and some trees.
Ectomycorrhizae: In ectomycorrhizal associations, the fungal hyphae form a sheath around the plant root cells and extend into the surrounding soil. Ectomycorrhizal associations involve a diverse group of fungi, including species from the Basidiomycota and Ascomycota phyla. Ectomycorrhizae are commonly associated with trees, particularly in temperate and boreal forests. Examples include pines, oaks, and birches.
Ericoid Mycorrhiza: Form associations between fungi and plants in the Ericaceae family, which includes heath and heather plants. The hyphae of these fungi can penetrate the cells of the plant's root cortex. Typically, fungi from the Ascomycota phylum are associated with ericoid Mycorrhiza.This type of Mycorrhiza is commonly found in plants like blueberries, heathers, and rhododendrons.
Orchid Mycorrhiza: Orchids often form unique mycorrhizal associations. Various fungi, including those from the Basidiomycota and Ascomycota phyla, can be involved in orchid mycorrhizae. Orchids, being highly dependent on these mycorrhizal associations, often require specific fungi for successful germination and growth.
Ectendomycorrhiza: Ectendomycorrhiza exhibit characteristics of both ectomycorrhiza and endomycorrhiza. The fungal hyphae form a sheath around the roots, but they also penetrate the root cells to some extent. Certain fungi, such as those in the genus Wilcoxina, are known to form ectendomycorrhizal associations. Ectendomycorrhizaeare found in some plant species, but they are not as well-studied as other types.
These diverse types of Mycorrhiza associations demonstrate the adaptability and specificity of these symbiotic relationships, catering to the unique needs of different plant species in various environments.
Ways to adjust Mycorrhiza to our plants:
Mycorrhiza inoculants, which contain spores or mycelium of Mycorrhiza fungi, can be added to soil in several ways to establish or enhance Mycorrhiza associations. These inoculants are available commercially and can be applied during planting or transplanting and even when preparing clones cuttings. In most cases, Mycorrhiza inoculants come in a powdered or granular form.
There are two main ways to applied them during planting/transplanting:
Slurry: Mix the recommended amount of inoculant with water according to the instructions on the package. This creates a slurry that can be applied directly to the plant roots by gently dipping or sprinkling.
Powder: By spreading with gentle touch apply directly the Mycorrhiza powder to the plant roots. Remember to water the plants thoroughly after planting to help the Mycorrhiza fungi establish contact with the roots and soil. Adequate moisture is essential for the initial stages of Mycorrhiza colonization
When preparing cuttings the idea is to dip gently the cut in the Mycorrhiza powder and then to stick the cut in the soil/rockwool-cubes and to sprinkle water on the cut.
It's important to note that Mycorrhiza inoculants are most effective when applied to plants that do not already have established Mycorrhiza associations. Additionally, the success of the inoculation process can be influenced by factors such as soil conditions, plant species, and environmental factors. Always follow the specific instructions provided by the manufacturer of the Mycorrhiza inoculant for optimal results.
Who Benefits from Mycorrhiza?
Farmers: Improved crop yields and reduced dependency on synthetic fertilizers make Mycorrhiza a valuable asset for farmers.
Plants: Mycorrhiza associations enhance nutrient and water uptake, leading to healthier and more resilient plants.
Ecosystems: Mycorrhiza contributes to overall soil health, promoting biodiversity and ecological balance.
summary
Understanding the role of Mycorrhiza in natural ecosystems is vital for conservation efforts, sustainable land management, and maintaining the resilience of diverse plant communities. It highlights the interconnectedness of plants, fungi, and the soil in creating and maintaining healthy ecosystems. Understanding its discovery, applications, and benefits in agriculture opens up new possibilities for resilient farming practices. As we continue to explore the intricacies of Mycorrhiza, it becomes clear that harnessing its potential is key to cultivating a thriving and environmentally conscious agricultural landscape.
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