Endo-Mycorrhizae VAM (What is it ?)

Image - Herb Museum Canada

Vesicular Arbuscular Mycorrhizae (more commonly refered to as VAM) - Endomycorrhizae
Image - Mycorrhizzas.info

Illustration - Cornell University
In a Nutshell

Both animated images above are illustrating the contrasting differences between Ecto & Endo Mycorrhizae. Remember how the Ectomycorrhiza forms around the various cell walls like mortar in between the bricks in a wall and it's fungal strands are so easily seen with the naked eye ??? Remember too that it also forms what we call fruiting bodies as science speak calls them or more commonly known by the average person as Mushrooms or Truffles. The Endomycorrhizae on the other hand actually penetrates and infects the inside of the cell walls and becomes part of the cells, they don't form fruiting bodies like mushrooms or truffles, but rather what are called Propagules which will be found under the ground among the roots which contain numerous spores. Their hyphal strands are also more difficult to see without some magnifcation, but sometimes easily recognized if someone knows what to look for. Take a look at an actual picture (illustrating fungal infection within a cell) of the internal workings the fungal connections provide within the cell walls.

Now take a look at the Propagules among roots.
Illustration by Mycorrhizal Applications Inc

Image - Cornell University

The most widespread of mycorrhizae are the arbuscular mycorrhizas (VAM), sometimes called vesicular-arbuscular mycorrhizas. These are found world-wide on many crop plants, wild herbaceous plants and trees, as well as on pteridophytes and some bryophytes. The fungi that form these mycorrhizas are members of the zygomycota, such as Glomus and Acaulospora spp. As the pictures illustrate, they have a different form of reporduction from the ecto-mycorrhizal varieties which form the familiar mushrooms and truffles were are all use to seeing and sometimes eating. They create what are known as propagules which contain numerous endo-mycorrhizal spores. These spores do not move theough the air as freely as those expelled bu the common mushrooms and puffballs. They are underground and various critters, bit insects and animals may spread them around, aisde from the fact that endo-mycorrhizae can move itself underground from plant to plant. This is important to know when attempting land restoration. Many time a biodiverse group of plants which are endo-mycorrhizal need to be grown together in order to counteract the negative chemical effects of a non-native weed invasion of non-mycorrhizal plants which send chemicals into the soils to disrupt the signalling between hose and fungi for colonization. In so doing they outcompete mycorrhizal plants. The sciencey faith affirmation, "You don't need to inoculate the soil because the fungal spores are just out there everywhere in the air" just doesn't work with this group of plants.

None of these can be grown in pure culture, away from their host plants. Take a look at how it is done. They usually have to be grown indoors as in a GreenHouse environment. They cannot be wild collect as in the case of Ecto - mushrooms and truffles etc. I remember that Plant Health Care Inc have or had commercial greenhouses somewhere in Texas where they used certain specific types of VAM Host Plants for this purpose. Unfortunately for the plants, they have to be killed during harvest, but that's how you get propagules for commercial mixes.
Illustration - University of Delhi

Magnified Image Propagules - HydroExperts

Image of Tomatoes - Mycorrhizal Applications Inc
Two above photos reveal what the propagules look like when magnified within the wild mycorrhizal grid of fungal network connnected to the roots. Oddly enough when using a endo.mycorrhizal blend, this must be worked into the ground as the spore size is too big to move in between the soil pores. No such problem with spores of Ecto-mycorrhizae which become air born and eventually washed into the soil where their tiny size has no such movement problems. This last photo above is taken from Mycorrhizal Applications Inc of Oregon where Tomato plants are hydroponically grown and the display here is of the mycorrhizal VAM colonizing the roots. However PHC also used this method in growing and harvesting VAM Propagules.

Practical Application: 

What Does Mycorrhizal Fungi Do for Plants?

Short Answer: 

  1. Plant roots give Mycorrhizal fungi sugars and a host (living plant roots)
  2. Mycorrhizal fungi helps plants in nutrient uptake, and aids in water and mineral collection.

How it works: 

  1. Mycorrhizal fungi uses carbon from carbohydrates (sugars) to grow. Plants make these carbohydrates through photosynthesis and excrete them to though its roots to feed the fungi. 
  2. In return, plant roots gain the increased nutrient absorbtion abilities of the fungus – Mycorrhizae mycelium has a higher absorptive capacity for water and mineral elements.

What's so good about it ??? 

  • The large surface area of mycorrhizae’s fungal hyphae act like an extension of the plant’s roots, called extraradical mycelium. Because they are smaller than roots, the microscopic hyphae are able to penetrate smaller spaces between soil particles. (read) 

  • Mycorrhizal Fungal hyphae also take up and store water to give to plants during dry periods, imporoving their resistance to drought. (read)

 Increased Phosphorus uptake:

  •  Plants frequently have trouble absorbing the major nutrient phosphorus (P), even when abundant in soil. This is due to P’s low solubility, low mobility, and its ability to bind itself with cations, forming unsoluble complexes that are unavailable to plants. 

  • Along with this, plants often develop a phosphate depletion zone around their roots. 

  • Mycorrhizal fungi produces powerful phosphatesolubilizing enzymes that are released into the soil, increasing phosphate solubility. These “digested” phosphate minerals are sent to the host by fungal hyphae transporters, reducing the metabolic energy needed by plants. (read) 

  • This study calculated that over 50% of P uptake by plants was absorbed via AM fungi, even when P was added to the soil.

Key Points:  Mycorrhizae increases the absorbing area available to the roots, and assists plants in water and mineral uptake.


How is Mycorrhizal Fungi Good For Soil?

Illustration by Michael Rothman
Short Answer:
  1. For nutrient cycling; To speed up decomposition of organic matter in the soil, resulting in more nutrients for plants to use.
  2. Fungi play an important role in the soil food web. The fungal energy channel fuels populations of microarthropods, other mesofauna, and beneficial microbes. 
Nutrient Cycling:
  • Undecayed matter such as the leaf litter, wood chips, rock powders and bone meals present in soils all contain nutrients that must be broken down into the smallest particle (ions) in order to be absorbed by plants. 
  • How do you get that? Decomposition. 
  • While all organic matter is subject to decomposition by microbial (fungi, bacteria) and environmental agents (i.e. rain, wind, sunlight), mycorrhizal fungi assists in creating enzymes that accelerate the decay of this matter. 
  • AM fungi has been shown to accelerate decomposition, as well as acquire nutrients such as phosphorus and nitrogen from organic material.

How it works: Mycorrhizae fungi works as a decay organism, mobilizing nutrients to be passed onto the host plant.  A recent study found that mycorrhizae is responsible for 50% of the annual throughput of biomass and for 43% of the nitrogen released annually in a Doulis fir ecosystem. (read)

What's so good about it?:

  • Mycorrhizae fungi can activate immobilized nutrients locked up in long-term nutrient sources present in the soil by decomposition. 

  •  Cannabis sativa L. (hemp) plants inoculated with mycorrhizal fungi have been shown to induce growth and absorb more toxic heavy metals from polluted soils. (read) 

  • Mycorrhizae fungi also can act as a pH buffer, allowing plants to recieve nutrients such as phopshate ions and iron that they could otherwise not obtain due to pH-related nutrient lockout. This is common in very acidic or very basic pH soils. (read) 

Key Points:

Mycorrhizal fungi assist in the creation of powerful enzymes that unlock immobilized nutrients such as phosphorus, iron, nitrogen and calcium from material sources in the soil.


 How to Increase Mycorrhizal Fungi in 4 Steps

Besides inoculation, here are 4 more tips that will help increase mycorrhizal fungi populations.

Increase Aeration

  • Mycorrhizae requires oxygen to breathe, so aerated soil-mixes helps for increasing the amount of mycorrhizal fungi that can live & colonize. 

  • Ways to increase aeration in the soil include mixing in non-porus material such as coarse sand, perlite or lava rock, or mixing in airy porus material such as vermiculite, rinsed coco coir or peat moss. 

  • Aeroponics has been shown to be more sucessful than hydroponics in harboring mycorrhizal fungi, due to the high oxgen level present in aeroponic systems.

 Increase Beneficial Bacteria

  • Mycorrhizal fungi thrives in soils with a high amount of aerobic, beneficial bacteria. There are complex interactions between beneficial soil microbes and the mycorrhizae. 

  • As a rule of thumb, anything that will slow down the soil bacteria will inturn slow down the mycorrhizal fungi. 

  • Ways to increase beneficial bacteria in the garden include using worm castings, compost teas and compost.

Apply Mulch

  • A mulch covering that keeps the topsoil cool and protected from the sun is ideal for cultivating mycorrhizal fungi. Too much heat or UV light can damage the delicate fungi, which is why mulching with organic matter is recommended.  

  • For example, a sub-tropical bean tree Inga (called the ice-cream bean tree) produces leaf litter high in nitrogen. Farmers in Honduras are using this tree to grow food crops in a method called "alley-cropping", where crops are grown in between rows of Inga trees. Alley cropping is great for mycorrhizal fungi because it replaces tilling and provides nitrogen-rich mulch for both plant and fungi to benefit. 

Avoid Disturbing the Soil

  • Reducing tillage has been repeatedly shown to increase AM colonisation and nutrient uptake. Soil tillage causes severe disruption to the mycorrhizae, resulting in delayed or reduced root colonisation and a reduction in the volume of soil that is exploited by the AM fungi. 

  •  However, the effects on growth and nutrient uptake are in some cases only temporary which is why it still may be beneficial for growers to occasionally till or disrupt soil if needed and re-inoculate.

What Mycorrhizal Fungi Doesn't Like

  1. Fungicides or fumigation will eliminate mycorrhizal fungi in the soil.
  2. Benomyl and thiophanate-methyl are used to suppress/eradicate AM fungi from soil and plants. (read)
  3. Compaction, use of high NPK fertilizers, hydrogen peroxide, Epsom salt, are harmful to AM fungi. 
  4. Excessive phosphorus in soil is detrimental to mycorrhizal fungi. You’ll get the most benefits from AM fungi if phosphorus levels are below 70 ppm.

Big thanks to Jared Cox for the above explanations 

Forget Monsanto's "Drought-Guard" seeds, you don't need them. Nature has something that's been around for 10s of 1000s of years

Image from University of Florida
This photo above is an experiment using Mycorrhizal Applications Inc's product called MycoApply to see how their endomycorrhizal blend of biodiverse species of fungi will compete against industrial conventionally grown corn in an extreme harsh environment of Florida Summer. In sandy soil of all things. A soil make up which is terrible for holding water. The MycoApply Corn is on the left and conventional science-based farmed corn on the right. What a contrast. But also notice how the endomycorrhizal fungi is moving underground and colonizing at least the first two rows of science-based grown corn on the right side ??? 😲 So the next time you hear of a Biotechnology company researching to develop a GMO Corn which will grow better in hotter climates if they can only just find that elusive drought-resistant gene, forget it. It doesn't exist anyway. Manipulating the genome perhaps of some kind desert plant hoping to make some kind of super heat and drought resistant GMO corn is bunk. Nature has always had the tools to meet the needs if scientists will just find and accept them. The problem has always been about money and once a system on a farm is healthy and replicates a wild ecosystem, there's no repeat money in it for them. So people individually will have to make their own decisions who they'll trust. Science or what we find in Nature.

More will be added as time goes on.

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