We as a species have always been fascinated by the unknown. The deepest depths of the ocean, the cold expanses of space – Our curiosity has never, and likely will never, be fully quenched.
How amazing it is then that there is a fungal network – The Mycorrhizal Network – under our very feet which to this day we are only beginning to understand.
Mycorrhizae play a key role in the ecology of our planet, carrying out a range of functions which we know are essential to plant life.
But why are Mycorrhizae so important? And how many complicated processes do they carry out for our subterranean life forms?
Much of this is still left a mystery.
What we do know however paints a fascinating picture. Keep reading for an overview of where the science currently stands, some background on Mycorrhizae, and just a few of the essential processes which they carry out, without which – Our world would be a very different place.
Let’s take a look.
What are Mycorrhizae?
The term ‘Mycorrhizae’ refers to a fungus which colonises plant roots, forming a symbiotic relationship with the host plant. Mycorrhizal fungi are ancient life forms, existing in this symbiotic fashion since the first plants began to spring up across the Earth’s surface.
From the plants point of view, the presence of Mycorrhizae leads to a distinct improvement in their ability to absorb both water & nutrients from the surrounding soil.
Meanwhile from the Mycorrhizae’s point of view, colonising the roots of plants allows them access to the simple carbohydrates essential for their survival. A true win-win situation.
The fungi themselves are microscopic in size, forming together into webs called ‘Mycelium’. These amazing fungal networks are sometimes referred to as sort of ‘Underground Internet’, and believe it or not can be measured in the hundreds, if not thousands of miles per square foot of soil. Truly amazing.
How do Mycorrhizae work?
These networks connect each and every plant in a given area together into what is known as a Mycorrhizal network, allowing for the exchange of various compounds between these interconnected plants as and when needed.
We don’t truly understand how this process works, but it’s easiest to visualise it as a sort of plant-based version of the internet many of rely upon each and every day.
Information – as well as essential nutrients – is passed back and forth throughout the network, with the Mycorrhizae facilitating this whole process.
The key to Mycorrhizae’s ability to carry out this essential role is their diminutive size.
Being so much smaller than a plant’s roots, Mycorrhizal fungi are able to access the tiniest pockets of essential nutrients buried within the soil, moving these nutrients throughout their network until harvested by the host plants.
This extends each plants ‘Reach’ by orders of magnitude, and is a huge reason why plant life has been so successful on Earth these past hundreds of millions of years.
Of course, they don’t carry out this service for free. No organism evolves to be hundreds of millions of years old by being a sucker.
The plants are required to pay for this essential service through the provision of excess sugars, which they transfer through their roots into the neighbouring soil until harvested by the Mycorrhizal network.
What are the different types of Mycorrhizae?
Mycorrhizal fungi are usually organised into two distinct categories, within which there are untold strains of individual fungi. These categories are:
The most common form of Mycorrhizal fungi, Endomycorrhiza are found present among the roots of around 80% of plant species in existence today. This includes our most commonly known forms of plant life such as Fruit Trees, Crops, Vegetables and Flowers.
Endomycorrhizal fungi penetrate the living cells of the plant root, creating an invasive symbiotic relationship with the plant. From here they carry out the same process of nutrient acquisition as their non-invasive Ectomycorrhizal counterparts.
Far less common than their Endomycorrhizal colleagues, Ectomycorrhizae are only seen present around between 5-10% of plant species. They are generally seen forming relationships with woody plants, such as Oak, Pine, Orchid and Rose.
They differ from Endomycorrhizal fungi in that the symbiotic relationship they develop with their host plants is non-invasive, with the fungi remaining on the outside of the living root cells at all times.
The processes carried out are seemingly identical between the two Mycorrhizae families, with their methods of symbiosis differentiating the two.
How do Plants benefit from Mycorrhizae?
As previously mentioned, plants benefit in a number of ways from the presence of a healthy Mycorrhizal network in the surrounding soil. Although improved nutrient acquisition if of course a huge bonus for them, it isn’t the only benefit to be had from their symbiosis with Mycorrhizae.
Improved Nutrient Acquisition
There are a number of nutrients which are key to healthy plant growth. Phosphorus, Magnesium and Nitrogen are three key elements which, without the Mycorrhizal network, many plants simply would not be able to harvest enough of to survive.
In areas where the soil is not particularly rich in these essential nutrients this becomes a key factor in a plant’s chance of survival. The tiny fungal hyphae are able to access pockets of these nutrients otherwise unobtainable to the plant’s roots, doubling up almost as a second set of micro-roots.
Improved Moisture Acquisition
As previously mentioned, thousands of miles worth of Mycorrhizae can be found in very small pockets of soil. These fibrous little strands of fungi are excellent at both absorbing and transporting excess moisture in the soil, making for far more drought-resistant plants.
As you can imagine, in areas where water is scarce, the presence of a healthy Mycorrhizal network can mean the difference between life or death for all the reliant plant life in that area.
Improved Disease,Toxin & Pest Resistance
The presence of Mycorrhizae has been shown to lead to improved plant resistance to Disease, Toxin and pests, leading to improved overall plant vitality.
This occurs due to a number of factors. Firstly, the presence of Mycorrhizal fungi around or within the root cells themselves serves as a physical barrier, guarding against soil-based diseases and toxins.
Secondly, a number of reactions take place within the plant’s roots when this symbiotic relationship is established, many of which have been shown to lead to increased disease and pest resistance, such as the stimulation of metabolites and the thickening of cell walls.
Lastly, much like us humans, improved health usually means improved ability to fend off diseases.
The extra essential nutrients provided through this symbiotic relationship has been shown to lead to stronger, more vigorous plants, which if disease strikes will be more able to it off than a stressed, malnourished counterpart.
A truly fascinating, and as yet not fully understood aspect of plant life – It has been shown that plants harness the power of the Mycorrhizal network to communicate with each other.
To do this, they use a family of chemicals known as ‘Infochemicals’. The makeup of these chemicals differs wildly, depending on the intended purpose. Some are used as a form of warning signal, some to prohibit the growth of another plant, while others still are used to transfer nutrients.
How this exact process operates, how much is instigated by the network versus the plants, and exactly how sophisticated or targeted these messages are – are questions which are as of yet, left unknown.
Debates are raging within the relevant fields, with active research currently being carried out with the hopes of shining a light on some of these mysteries.
Nonetheless, what we do know is that plants do communicate with each other, and to do this they harness the most powerful informational web known to this planet for many millions of years, and perhaps even to this day – The Mycorrhizal network.
How does Mycorrhizae affect soil structure?
Something which is often overlooked when it comes to Mycorrhizae’s effect on its surroundings is soil structure.
When you’re looking at thousands of miles worth of Mycorrhizal fungi in as little as a square foot of soil, it’s hard to imagine just how much life you’d be looking at when considering the soil base of a field, or brook, or entire forest.
Over these large expanses the Mycorrhizal network becomes a vast web of life, constantly working its way through the soil in search of nutrients. And it turns out that this constant dynamism within the soil is essential to its health.
Soil-aeration and water-permeability levels are hugely important when it comes to creating a healthy environment for plant growth. Without a well-aerated soil, roots will find it difficult to spread and establish themselves, making life much harder for the overall organism.
Likewise with compacted, impermeable soils moisture will have a much harder time working its way through the various layers, leaving roots to dry out and die.
In this way, Mycorrhizal activity is more than simply a communication and transportation network, living symbiotically with the plant life above it. It is also a key player in creating the healthy soil environment which the plants need to survive to begin with.
Simply one more reason why Mycorrhizae is essential to the ecology of our planet.
Wrapping Things Up
And there we have it, a brief view into the wonderful world of Mycorrhizal fungi. It really is a fascinating subject, of which so much is still to be learned.
Be sure to check back for some more in depth articles into Mycorrhizae and their comings and goings, as the scientific picture is sure to change over the coming years.
As always I hope this guide has been useful. If you’d like to be kept in the loop of whatever comes next from us here at the EcoGeeks then please feel free to subscribe below.
Have a great day.