Subject: BD Now! Mycorrihzae and Cole Crops?

From: Steve Diver <[email-masked]>
Date: Sat, 20 Aug 2005 20:08:16 -0500

Hugh -

The sod strips you employ for intercropping do
provide many "edge" effects.

The soils you've built to over 3% OM -- with
a full diversity of soil biota, humic substances,
and clay-humus complexes -- would provide
far more interesting results in sustainable cropping
research than typical agricultural experiment
stations.

The observations you made on root hairs on
cole crops were very interesting, but I'm not sure
they amount to eye-ball confirmation of mycorrhizal
colonization. VAM determination normally requires
staining or microscopy.

It is generally accepted that brassicas / crucifers
are non-mycorrhizal, in part because they are
early successional species, but also because they
have many root hairs.

The following passage on fine root hairs might be
relevant to your observations.

“Some plant species, such as crucifers (i.e. broccoli) are
unusual in that mycorrhizal symbioses are absent.
Species with fine root hairs and many root hairs are not
as dependent on mycorrhizae as species with well-defined
tap roots” (Coyne, 1999).

Source:

Soil Fungi
University of Western Australia
http://www.soilhealth.segs.uwa.edu.au/components/fungi

On the other hand, there are several papers that
describe mycorrhizal colonization of brassicas in
nature, and in mycorrhizal inoculated plants.

In the "A Check-List of Mycorrhiza in the British Flora",
the authors say the Cruciferae family has many
species that are never or rarely mycorrhizal.

On the other hand, they found that about one-third
of the cruciferae species examined in the British isles
were colonized by vesicular-arbuscular mycorrhiza.

Harley, J.L and E.L. Harley. 1987. A Check-List of
Mycorrhiza in the British Flora. New Phytologist,
Vol. 105, No. 2. p. 1-102.

The Mycorrhiza Information Exchange Database
at University of Tennesse has a search engine.

When you enter "brassica" or "crucifer", it
returns citations that show experiments where
broccoli and related cole crops were inoculated
with mycorrhizae. Sometimes they are definitely
colonized by VAM fungi.

Mycorrhiza Information Exchange Database
http://mycorrhiza.ag.utk.edu

It's too bad that money and freedom-to-choose
research projects are lacking among agricultural
researchers, especially for those of us in
alternative agriculture.

It would be interesting to see what all you
could find on your farm with the support
of scientists and their laboratory equipment.

Steve Diver

_______________________________________________

BDNow mailing list
[email-masked]
You can unsubscribe or change your options at:
http://lists.envirolink.org/mailman/listinfo/bdnow
delivered to: [email-masked]

---

From: Steve Diver <[email-masked]>
Date: Wed, 24 Aug 2005 17:53:11 -0500

Hello Hugh -

Thanks for sending the images of root growth and your
thoughts.   I guess they didn't make it on the BD-Now
archives, so I've copied your "text" below. 

I'm fascinated by the simple observation method that you present. 

Roots and rhizosheres and associated microorganisms are topics
that I've spent years looking into and thinking about.

I'm not sure if you suggest those rooting patterns are
VAM-derived hyphae radiating outwards, or maybe
you suggest that VAM-colonized roots are stimulated
to *proliferate*, in the zone that you describe. 

Regardless, my ears are pricked up and will keep
thinking and learning.   I've got tremendous respect
for the BD farming experience you and others bring to
this group. 

The following online book from Australia is superb.

Working with Mycorrhizas in Forestry and Agriculture
Australian Centre for International Agricultural Research  (ACIAR)/
CSIRO Forestry and Forest Products
http://www.ffp.csiro.au/research/mycorrhiza/

Especially see Section 3. on VAM, and the following
quote.

Section 3.  ARBUSCULAR MYCORRHIZAS
http://www.ffp.csiro.au/research/mycorrhiza/vam.html

"The network of hyphae in the soil is only connected to roots
by the entry points that initiate (VAM) mycorrhizal associations,
as hyphae do not grow out of living roots."

Also see Section 4. on Ectomycorrhizas.

Section 4.  ECTOMYCORRHIZAS
http://www.ffp.csiro.au/research/mycorrhiza/ecm/ecm.html

I'm still open to your observation-based method,
but wondering how it jives with the vasicular arbuscular
mycorrhizal knowledge base.

Interestingly, Walter Goldstein's research on BD
influence on rooting patterns might be relevant to
this discussion.

There are definitely differences in rooting patterns
based on organic matter, soil biology, and humic
substances.

With regards,

Steve Diver

Hugh Lovel wrote:

> Dear Steve,
>  
> Occasionally I run into the information that one cannot see 
> mycorrhizae on plant roots with the naked eye. More accurately you 
> cannot see how dense VAM colonization is at the root tip as it occurs 
> since it is an endophyte and it grows outward from the point of 
> colonization. But look back from the growing tip to a few days' 
> previous growth and you will have a very good idea of the density of 
> colonization by what has grown out. Look at the picture included in 
> this e-mail and you will see what I mean.
>  
> I'm sorry to say it is not the right time of year to take pictures of 
> VAM colonization on my turnip, mustard and rape roots. Maybe in 
> October if I am still in Blairsville, or maybe next April or May from 
> Northern Queensland I'll have an opportunity to take such pictures. 
> Anyway, take a gander at the current picture. You'll see no fuzz, of 
> course, at the root tips. But go back an inch or so and it clots the 
> soil on the roots with a dense fuzz. Every plant has these in the 
> soils at Union Agricultural Institute. This picture was taken the next 
> morning after a hard downpour the previous afternoon. Generally it is 
> easier to take pictures of mycorrhizae given dry conditions.
>  
> VAM colonization of grass roots at Union Agricultural Institute, 
> Blairsville, Georgia
>
> VAM on Klass Marten Farm, upstate New York
>  
> Sorry that these pictures won't post to BDNow!, but see what you think 
> anyway. Someday I'll get you pictures of mycorrhizae on Cole crops. 
> Rape, mustard or turnip would be easy at the right time of year here 
> at UAI, but I don't have those conditions at the moment.
>  
> Best,
> Hugh

BDNow mailing list
[email-masked]