How Do Mycorrhizal Fungi Help Plants?


Do you always have trouble when it comes to getting good yields with your vegetables or flowers? A damaged or underdeveloped root system might be the cause because you have never maximized the use or even investigated how mycorrhizal (plural mycorrhizae) fungi can benefit your plants. If you have ever decorated a Christmas tree, enjoyed the shade of an oak, eaten a chanterelle or a blueberry then you have benefited from mycorrhizal fungi – it makes the survival of most plants possible.

How do Mycorrhizal Fungi Help Plants? Mycorrhizal Fungi helps plants as they work synergistically with the plant to provide additional water and nutrients that the plant’s root system would not be able to reach alone. The fungi attach itself to the root system and helps to increase the mass of the plant’s root system. In turn, the plants provide carbohydrates that the fungi need to survive.

What are mycorrhizal Fungi?

Have you ever had to work in a garden or simply grow a single plant? If so, you definitely know it requires hard work – you must carefully cultivate the growth of your plants by keeping every weed at bay and also offering the plants with enough essential requirements including water and sunshine. And in the end, your efforts and hard work are rewarded with plenty of healthy nutrients in the form of fresh, delicious vegetables or a backyard of beautiful flowers.

Are you aware that many plants have their own gardens too? Unlike our natural gardens, the plants’ gardens are underground and usually, you can not see them except for a short period each year. These “plant gardens” are called mycorrhizae – they live in a symbiotic relationship with the plants.

Mycorrhizae are literally fungi that exist as very tiny, entirely microscopic threads referred to as hyphae. They are interconnected into a net-like web (mycelium) that measures thousands of miles all packaged into a tiny area around the root system of a plant. Mycorrhizae can also be described as the symbiotic relationship between a fungus and the root of the plant.

This association is referred to as symbiotic because the relationship benefits both organisms. The macrosymbiont (the plant) accesses increased exploration of the soil (rhizosphere) with the intricate hyphae net that raises water and nutrients uptake from soil interphase. While the microsymbiont (the fungus) uses carbon offered by the plant for its physiological purposes, growth as well as development.

How do the microbes and nutrients get into a plant?

This is basically a microscopic view of the roots. Most folks think the roots are pieces of plants underneath that soaks up water. The root system acts as an anchoring device – roots holds plants in the ground. Whether it’s a tree or a turf, roots are the anchor.

The root hair – something we can’t see with naked eyes – if these hairs get damaged and/or soil surrounding them is full of salts such that the nutrients and microbes load can’t enter into these root hairs, the soil becomes useless to both you and your plants.

So once mycorrhizae fungi get into root hairs, they expand them and continue to grow as they feed on roots. They simply establish a symbiotic relationship. As long as you feed your soil with the right nutrients, these fungi stay alive for longer than you could imagine!

Relationship between mycorrhizal fungi and a plant

Most importantly, if you want to determine how mycorrhizal fungi can significantly benefit your plants, consider using these inoculants in the next growing cycle. Ideally, there are various factors that influence both plant nutrition and yield.

Apart from plant genotype, water availability and uptake, environmental factors like availability of nutrients in the growing media, and the ability of a certain plant to properly use what is available in the soil, they all play an important role in plant growth.

To enhance these processes, plants form a mutually beneficial association with arbuscular mycorrhizae. These soil fungi play an integral role in plant nutrition by enhancing water and nutrients uptake from the soil and can form a mutualistic symbiotic relationship with very many plant species (more than 85%) inclusive of all major agricultural as well as horticultural crops.

The fossil evidence proposes that this symbiotic association dates back to more than 400 millennials and played an important role in enhancing plants mitigation from seas onto dry land and also using of terrestrial habitats. Without arbuscular mycorrhizal fungi, nowadays crop plants would probably not exist nor would there be life on land as everybody knows.

This association is initiated after mycelia are manufactured through a spore and stretch to connect with plant root. Mycelia penetrates the cell membrane, stretching into the root cortex hence bridging a gap between soil biome and root. These fungi establish arbuscules (specialized structures that act as nutrient exchange sites within the cell) and vesicles (acts as storage sites). In this symbiosis, the plant is offered better access and also the uptake of water and nutrients from the soil. Mycorrhizal fungi help with these processes in favor of photosynthetic carbon from plants.

How do mycorrhizal fungi help plants?

The beneficial growth and development responses to mycorrhizal fungi are best attributed to the following mechanisms:

  • Increased soil’s physical exploration
  • Increased availability of nutrients within growing media
  • Increased uptake of nutrients
  • Access to storage sites of all absorbed minerals
  • Decreased salts and toxic minerals uptake

Increased soil’s physical exploration

The increase in absorption of different mineral nutrients inclusive of phosphorus by most mycorrhizal plants has been credited to raise the surface area for plants’ nutrient absorption. The root system of the plant act as the main absorbing organ of both water and mineral nutrients.

Inside the soil, the roots of plants are limited to a small surface area for nutrients absorption while hyphae (of arbuscular mycorrhizal fungi) develop out beyond the depletion area where plant roots have already absorbed all the available nutrients and water.

In fact, the absorptive surface area of roots that can go up to 50 times in every mycorrhizal plant (with fungal hyphae reaching beyond the root section by 4 to more than 20 cm) when compared to non-mycorrhizal plants.

Increased availability of nutrients within growing media

A number of researches claim that mycorrhizal fungi can solubilize otherwise insoluble nutrients. The activity of mycorrhizal phosphatase enzyme converts all phosphate into soluble forms and allows mycorrhizal plants to absorb more phosphorus than non-mycorrhizal ones. Studies demonstrate that the extraradical hyphae (of Glomus intraradices) were readily able to hydrolyze exogenously produced organic phosphorus and also transporting significant amounts of phosphorus to plant roots.

Various mycorrhizal plants like wheat, marigold, corn, and onion can raise the activity of phosphatase in roots and so organic phosphorus hydrolysis. It’s evident that molecular changes brought about by mycorrhizal fungi in plant roots raise the ability of plants to convert insoluble organic phosphorus into bioavailable phosphorus forms.

This fungi also plays an integral part in uptake as well as the conversion of nitrogen into bioavailable forms. Mycorrhizal increases decomposition and also subsequent inorganic nitrogen capture from complex material like plant litter. The fungi can facilitate organic residues’ degradation and uptake of nitrogen by the host plant.

Increased uptake of nutrients

The rate of nutrients uptake facilitated by mycorrhizal fungi is generally faster compared with non-mycorrhizal roots. This fungus possesses a high affinity for mineral ions as well as lower threshold concentration to absorb than what plant roots do. The finest mycorrhizal hyphae in the soil typically have a diameter of about 2 μm when compared to fine-root diameters of 100-500 μm and root-hair diameters of 10 to 20 μm. Therefore, it’s evident that hyphae are about 10 times more efficient than root hairs and 100 times than fine roots.

Access to storage sites of all absorbed minerals

As explained earlier, arbuscular mycorrhizal fungi form specialized structures (vesicles) that serve as storage sites inside the roots of a plant and also store absorbed lipids and minerals. These absorbed nutrients act as reserves, becoming easily accessible by host plants when there is a limited supply.

Decreased salts and toxic minerals uptake

Mycorrhizae have demonstrated to offer protection to plants from not only saline conditions but also the uptake of heavy metals, assisting the plant to prevent nutrient lockout situations. These fungi can mitigate salts’ uptake thus balancing the uptake of toxic ions like Na+ and Cl- hence permitting plants to uptake other useful ions like K+, Mn2+, and Ca2+.

Also, plants colonized by mycorrhizal fungi have been claimed to possess a buffer in between heavy metals and plants avoiding the uptake of other elements such as zinc, copper, aluminium, and arsenic. This may be the very reason why Studies have been inconclusive when growing potatoes in tires. Check out that blog here.

Heavy metals accumulation in plants can result in various symptoms like suppressed growth and development, chlorosis, roots browning and to the extreme cases, death of plants. This resistance of heavy metals has been found to manifest through the sequestration of these metals in most fungal tissues as well as by improved nutrition of phosphorus in plants.

Conclusion

Mycorrhizal fungi use, especially in greenhouses production is definitely a no-brainer. Through plant-root connection and hyphal mass, these fungi assist in raising the absorption of water, raise uptake of nutrients, increased availability of nutrients that aren’t available to the roots of plants and protection from harmful minerals or excess salts.

Moreover, these fungi are capable of extending farther into the soil than plant roots because they possess various mechanisms to make sure your plants get the desired TLC. With no doubt, this is a truly beneficial association for the plants and also the container growers.

To determine how mycorrhizae can ultimately benefit your plant then consider applying these inoculants during your next growing cycle. Or at the minimum running a comparison trial in order to see how you can lower the inputs and increase plant performance by maximizing on mycorrhizae usage. Sooner or later, you will notice the power of these fungi when it comes to rooting!

I hope you enjoyed this blog post about Mycorrhizal Fungi. I trust it answered your question fully. If this was of interest to you, why not consider subscribing to the blog so you don’t miss future content.

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And remember folks, You Reap What You Sow!

Tony O'Neill

I am Tony O'Neill, A full-time firefighter and long term gardener. I have spent most of my life gardening. From the age of 7 until the present day at 45. My goal is to use my love and knowledge of gardening to support you and to simplify the gardening process so you are more productive

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