[permaculture] mycorhizae thread - this gem of info: plant selection of appropriate VAM's & VAM-stimulating natural plant extracts

Lawrence London lfljvenaura at gmail.com
Sat Mar 23 15:36:53 EDT 2013

Vesicular-arbuscular and Arbuscular Mycorrhizas
by L.E. Chinnery
Vesicular-arbuscular mycorrhizas (VAM) and arbuscular mycorrhizas are
mutualistic symbioses formed between the roots of
most plants and fungi in the order Glomales.


This is the commonest type of mycorrhiza and can be found in almost
all plant communities, natural and agricultural.
Vesicular- arbuscular (VA) and arbuscular mycorrhizas are
endomycorrhizas formed by Zygomycete like fungi and the roots
of most families of Angiosperms as well as Gymnosperms, Pteridophytes
and Bryophytes (liverworts). Non-mycotrophy in the
Angiosperms appears to be restricted primarily to the families
Amaranthaceae, Brassicaceae, Chenopodiaceae and
Zygophyllaceae, and many hemiparasitic plants. The mycorrhizal host
may be facultatively or obligately dependent on its
fungal partner. It appears that these mycorrhizal associations are
evolutionary very old and that other types of
mycorrhizas and non-mycotrophy evolved more recently. In fact, it has
been speculated that VA mycorrhizas may have been
involved in the successful invasion of land by vascular plants and
played a controlling influence on the evolution of
roots. Unlike many of the fungi involved in other types of mycorrhiza,
these mycorrhizal fungi cannot be cultured in the
absence of plant roots or a root organ culture.

-------- Original Message --------
Subject: Re: [SANET-MG] Soil phosphate (was organic vrs conventional)
Date: Tue, 9 Nov 2010 22:07:35 -0500
From: Jerome Rigot <jfrigot at GMAIL.COM

Hi Edna,

Mycorrhizal fungi are microorganismes that form a symbiotic relationship
with plants, providing nutrients not readily bioavailable in exchange for
sugars the plant provide. One of the main mineral nutrient these organisms
help make available to plants is phosphate. Generally, there is always a
very large amount of phosphate in the soil that is not bioavailable to
plants, but the fungi extend their hyphae much farther than the root hairs
can, and release organic acids that not only transform the phosphate into a
more bioavailable form, but transport it back to the plant.

Actually, research has shown that adding readily available phosphate
(synthetic fertilizers such as superphosphate) into the soil prevent the
mycorrhizal fungi from forming these symbiotic relationships with the
plants. Mycorrhizal fungi bring several other benefits to plants, such as a
higher resistance to diseases.

Anyway, I hope that helps.


-------- Original Message --------
Subject: Re: [SANET-MG] Soil phosphate (was organic vrs conventional)
Date: Tue, 9 Nov 2010 20:58:17 -0800
From: Barry Lia <barrylia at COMCAST.NET

Mycorrhiza (2004) 14:145–163
Roger T. Koide · Barbara Mosse
A history of research on arbuscular mycorrhiza

Micorrhizae were first crudely described in 1842 and study of their
symbiosis taken up in ernest in the 1880's. The first evidence of
their role in phosphorus uptake came in about 1959.

My text should have read: The role of mycorrhizal fungi in phosphorus
uptake wasn't recognized in 1910...
Barry Lia \ barrylia at comcast.net
<http://lists.ibiblio.org/mailman/listinfo/permaculture> \ Seattle WA

On 12/29/2010 1:08 PM, Beginning Farmers wrote:
>* Speaking of microorganisms and phosphorus...*>**>* In the late 1980's researchers at Michigan State did a simple experiment*>* with white clover grown in the presence of mycorrhizae (which is extremely*>* important in phosphorus uptake by plants). In the experiment they used some*>* soil that was phosphorus deficient, and some that had plenty of available P.*>* What they found was that the P deficient plants were colonized by the*>* mycorrhizae at much higher levels than the plants that had plenty of*>* phosphorus.*>**>* A curious result. But that's not where the story ends. Based on this result*>* it was postulated that the plants were actually sending out a 'signal' when*>* they were under P stress that 'told' the mycorrhizae 'we need help'. Another*>* researcher, Muralee Nair, was able to isolate a compound called formononetin*>* - an isoflavanoid (think soybeans) that was responsible for the signal.*>* Formononetin was present in such small quantities that Nair didn't believe*>* the results at first. But after isolating and synthesizing the compound, he*>* consistently got significant increases in not only mycorrhizal colonization*>* but also rhizobial nodulation (associated with nitrogen fixation) in*>* legumes. You can get the paper for free here:*>* http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1991.tb00568.x/abstract*>**>* When I was working with them testing the product, we were able to get*>* significant increases in plant growth and production by applying*>* formononetin at levels as low as 30 grams (yes, grams) per acre! I tested*>* this product on plants all over the country with mixed yield results (I*>* never saw significant decreases, but sometimes didn't get increases) - which*>* I attribute to the fact that conventional farmers typically apply so much*>* phosphorus that increased mycorrhizal colonization doesn't always result in*>* increased yield.*>**>* Just another example of the beautiful complexity of nature, the wonders of*>* symbiotic convolution, and the importance of healthy living soils for*>* optimal plant growth.


High CO2 Stimulates Soil-Building "Glue"
ARS News Service
Agricultural Research Service, USDA
Don Comis, (301) 504-1625, dcomis at asrr.arsusda.gov
August 12, 1999
In the first examination of the effects of high atmospheric carbon
dioxide levels on soil structure, an Agricultural Research Service
scientist and cooperators found that the gas stimulates soil-dwelling
fungi to produce more of a unique protein that greatly amplifies a
soil's ability to store carbon. The study's results are described in a
letter published in the August 12 issue of Nature magazine. One of the
letter's authors, ARS soil scientist Sara F. Wright, previously
discovered the protein and named it glomalin. She suspects it may be the
primary glue that holds soil together. Now it appears that a little of
this glue goes a long way toward helping soils keep carbon out of the
atmosphere in the form of carbon dioxide.

Date:         Fri, 11 May 2001 08:18:07 -0500
Sender:       Sustainable Agriculture Network Discussion Group
From:         "Wilson, Dale" <WILSONDO at PHIBRED.COM
Subject:      Chitin in laymans terms

Two basic strategies for mechanical support are found among living
things, bones/muscles and tough, hard shells.  Plants, fungi, insects,
spiders, and crustaceans (including lots of tiny, tiny soil creatures)
have shells or cell walls.  Most of these exoskeletons and walls are
made of sugar molecules spun together to make long chains.  The sugar
molecules are connected by a kind of linkage or bond that is very
resistant to breakdown (unlike starch, which is easily broken into
sugar). The plants make cell walls mainly out of cellulose, the main
constituent of cotton and wood.  The animals (and most fungi) that make
cell walls and exoskeletons make them out of a substance very similar to
cellulose called chitin, also fiberous and hard to break down.  It is
almost identical chemically to cellulose, except the sugar molecules
have an amino group (contains N) stuck on the side.

The fact that chitin contains all this nitrogen has important
implications ecologically.  Nitrogen is a scarce resource in most
systems (well, not if you apply 200 lb/a!), and chitin is an important
source of N, and sugar in many systems.  There has been great pressure
for the evolution of organisms that can exploit this resource.  In soils
with a large currency of chitin (soils with a lot of fungi) there are
also many organisms that eat chitin for breakfast.  In such situations,
chitin is less effective as armor plate. It so happens that nematodes
use chitin as armor plate, and of course most fungi do to.  Soil with a
high rate of formation and breakdown of chitin is less hospitable to
nematodes and fungi.  Flora must spend more energy
defending itself.  Plants have ways of exploiting this situation at the
root/soil interface.  It is all wonderfully complex and, well,
miraculous (also very violent on a tiny scale).




Date: Tue, 28 Mar 2000 09:51:57 -0500
To: ARS News List <ars-news at ars-grin.gov
Subject: Adding Microbes to Transplant Mix
Adding Microbes to Transplant Mix Helps Increase Crop Yields
ARS News Service
Agricultural Research Service, USDA
Jesus Garcia, (301) 504-1627, jgarcia at ars-grin.gov
March 28, 2000
Tomato and pepper farmers can now add microbes along with their
transplant mix to the arsenal of production practices used to reduce
yield losses caused by soilborne pathogens--including root-knot
nematodes. The microbe-amended transplant mix is being developed by
Agricultural Research Service scientists at the U.S. Horticultural
Research Laboratory in Fort Pierce, Fla., led by Nancy K. Burelle, in
cooperation with Gustafson LLC of Plano, Texas. The transplant mix,
called BioYield 213, is amended with two naturally occurring soil
microorganisms--Paenobacillus macerans and Bacillus amyloliquefacien.

Here's an interesting article on release of rock

One on chitin:http://www.ibiblio.org/ecolandtech/orgfarm/agronomy/chitin.txt

and ARS News Bulletin:
Boosting organic matter in soil creates a healthy environment for
soil-dwelling bacteria that suppress


The soil population is so complex that it manifestly cannot be dealt
with as a whole with any detail by any one person, and at the same
time it plays so important a part in the soil economy that it must be
--Sir E. John Russell "The Micro-organisms of the Soil", 1923


-------- Original Message --------
Subject: Re: [SANET-MG] Soil solution concentrations of phosphorus
Date: Thu, 30 Dec 2010 16:19:36 -0500
From: James Kotcon <jkotcon at WVU.EDU

Here in West Virginia, both VAM and ectomycorrhizal fungi ARE
ubiquitous.  We typically find 10-20 species/100 cc in most agricultural
soils, and will even find several species on reclaimed mineland soils.
These are "soils" that are literally created from mine spoil out of
crushed bedrock.  It appears that they are inoculated from several
sources, including previously colonized transplants brought in for
re-seeding, as well as wind blown spores.  Within a few years after
reclamation, the soils are loaded.

It is true that root colonization tends to be very limited in
agricultural soils, largely due to inhibition by large amounts of
phosphate in heavily fertilized soils..  Hence high levels of root
colonization tend to occur only in phosphorus deficient soils, or in
native ecosystems.  But low root colonization is not the same as "wiping
out" the species.  In our experience, although root colonization can be
reduced, anything short of broad spectrum biocides (e.g., methyl
bromide) is unlikely to wipe them out.

Given the low host specificity and the functional similarities of many
VAM species, we have found it difficult to demonstrate a benefit of VAM
inoculation except in fumigated nursery beds or similar special
situations.  Of course, there are species-specific differences
associated with things like induction of disease tolerance in infected
crops, but it is difficult to make broad generalizations because these
vary among crop, VAM species, and plant pathogen.

Perhaps others know how to make them work, but I have rarely seen
consistent benefits from field inoculations, except where soils are low
in phosphorus or similar elements.

Jim Kotcon


The most beautiful thing we can experience is the
mysterious. It is the source of all true art and science.
 -- Albert Einstein

On Sat, Mar 23, 2013 at 1:44 PM, Lawrence London <lfljvenaura at gmail.com>wrote:

> There are more posts in this thread in the sanet-mg archives that this
> forwarded post from me was included in.
> There were replies with a lot more info on :
> 1) "determine how the different crop plants differentially select for
> certain
> species of VAM among all that are availible in the soil."
> 2) "that certain natural, plant-produced chemicals can
> stimulate the existing VAM to higher levels of activity.  These
> chemicals were originally derived from red clover"
> [a group actually produced such extracts to make a marketable ag product
> from]
> I will find them and post them here.
> <>
> Article: 5512 of bionet.plants
> From: niemirab at student.msu.edu  (Brendan A. Niemira)
> Newsgroups: bionet.plants
> Subject: Re: Mycorhizzae vs. Fertilizer
> Date: Thu, 02 Mar 1995  11:04 est
> For agronomic crops, you're talking about vesicular arbuscular
> mycorrhizae (VAM), a symbiotic endomycorrhizal fungus.  These are
> ubiquitous anyway, and
> not very host-specific, so there is very little need to inoculate the
> field in order
> to introduce them.  The big trick is getting them to colonize your crop
> plant to such an extent that fertilizer inputs can be reduced.  You can a)
> build up the population in the soil such that even moderately active fungi
> result in
> heavy coloniazation, b) put something in the soil to stimulate the activity
> of smaller populations to get heavy colonization.
> Crop rotations have been shown to have a definite impact on the population
> dynamics of VAM, and work is currently being done (by me, among others) to
> determine how the different crop plants differentially select for certain
> species of VAM among all that are availible in the soil.
> Other workers have shown that certain natural, plant-produced chemicals can
> stimulate the existing VAM to higher levels of activity.  These
> chemicals were originally derived from red clover, a popular sequence in
> crop
> rotations.  This may shed some light on why rotations are effective
> w/regard to VAM.

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