Re: [compost_tea] Exudates (was: Re: Brassicas and vam fungi)

From: Thomas Giannou <thomas_at_tandjenterprises.com>
Date: Mon, 1 Nov 2004 16:46:37 -0800

Ahhhh...

But back to the original question... can Brassica be coplanted with mycorrh=
izal plants and not have the Brassica kill off the AM fungi on the mycorrhi=
zal plants? RESEARCH papers indicate they can be coplanted in certain situ=
ations. Several research papers even indicate that brassica can be benefit=
ed by being in the presence of endomycorrhiza fungi even though the brassic=
a are not colonized. There are a few research papers that also show certai=
n Brassica are or can be colonized by endomycorrhiza fungi (see more exampl=
es below). We should keep in mind that the Brassica family covers a fair n=
umber of plants and everything MAY NOT be equal among those plants. For ex=
ample, just because I have found that certain brassica plants can be coloni=
zed by endomycorrhiza, that does not mean that ALL brassica plants can be c=
olonized. I posted one research finding earlier that said if the mycorrhi=
zal plants and the brassica plants were planted at the same time, there was=
 no problem for the AM fungi. It would be interesting to see if that would=
 hold true with a variety of different brassica vegetable plants. In that =
same document, if the Brassica were planted 30 days in advance, then the AM=
 fungi was inhibited in its colonization of the mycorrhizal plant roots. T=
hese tests were conducted with the addition of endomycorrhiza fungi to the =
mycorrhizal plants.

Regarding a common red radish (a brassica member I think) we were able to p=
lant radishes this year in the highest temperatures in summer (3 rd week of=
 July with daily temps around 98 F) and sprayed them weekly with our Microb=
e Tea with Yucca added and they grew in to be nice and crispy and well form=
ed. They weren't woody or super hot and they didn't bolt as is common for =
radishes planted in hot weather.

Here's a research paper extract that talks about exudates from Brassica....
                                  -----------------------------------------=
-----------------------------------------------
VIERHEILIG H; OCAMPO JA. 1991. ROLE OF ROOT EXTRACT AND VOLATILE SUBSTANCES=
 OF NONHOST PLANTS ON VESICULAR-ARBUSCULAR MYCORRHIZAL SPORE GERMINATION. S=
YMBIOSIS. 9(1-3)199-202.
Address:

VIERHEILIG H, CSIC,ESTAC EXPTL ZAIDIN,DEPT MICROBIOL,E-18008 GRANADA,SPAIN=
 


Glucosinolates, substances found in crucifers, are metabolized to antifunga=
l, volatile and nonvolatile isothiocyanates. Vesicular-arbuscular (VA) myco=
rrhizal symbiosis is not developed in the Cruciferae. The effect of exposin=
g root extracts or their gasesous components from host (tomato, alfalfa) an=
d non-host plants (cabbage, rape, radish, spinach) to spores of Glomus mass=
eae were studied. The results suggest that the inhibitory effect of root ex=
tracts of non-host plants (Crucifereae) on spore germination can not be att=
rributed solely to presence of volatile substances and extended to other no=
n-host plants.
                             ----------------------------------------------=
-----------------------------------------

Here's another research paper abstract that says VAM fungi colonized and be=
nefited cabbage plant roots..

                  ---------------------------------------------------------=
-----------------------------------------------------------


Nelson R; Achar PN. 2001. Stimulation of growth and nutrient uptake by VAM =
fungi in Brassica oleracea var. capitata. BIOLOGIA PLANTARUM. 44(2):277-281=
.

Address:

Univ Durban Westville, Dept Microbiol, ZA-4000 Durban, South Africa.


Cabbage (Brassica oleracea, var. capitata, cv. Hercules) seedlings were ino=
culated with vesicular-arbuscular mycorrhizal (VAM) fungi Glomus fasciculat=
um, G. aggregatum,, and C;. mosseae. Differential efficiency in mycorrhizal=
 colonization and the specificity of fungal symbiont to stimulate the growt=
h and nutrient uptake of the host were observed. In addition, there was an =
increase in phenol, protein, reducing sugar contents, and peroxidase activi=
ty in the VAM inoculated seedlings. Since these compounds are known to conf=
er resistance against fungal pathogens, the use of VAM as a biological cont=
rol agent to protect cabbage against several root diseases is suggested.
                                         ----------------------------------=
-----------------------------------

Here's another abstract that seems to indicate cabbage seedlings were colon=
ized and benefited with AM fungi...

                                         ----------------------------------=
------------------------------------------


Nelson R; Achar PN. 2001. Stimulation of growth and nutrient uptake by VAM =
fungi in Brassica oleracea var. capitata. BIOLOGIA PLANTARUM. 44(2):277-281=
.

Address:

Univ Durban Westville, Dept Microbiol, ZA-4000 Durban, South Africa.


Cabbage (Brassica oleracea, var. capitata, cv. Hercules) seedlings were ino=
culated with vesicular-arbuscular mycorrhizal (VAM) fungi Glomus fasciculat=
um, G. aggregatum,, and C;. mosseae. Differential efficiency in mycorrhizal=
 colonization and the specificity of fungal symbiont to stimulate the growt=
h and nutrient uptake of the host were observed. In addition, there was an =
increase in phenol, protein, reducing sugar contents, and peroxidase activi=
ty in the VAM inoculated seedlings. Since these compounds are known to conf=
er resistance against fungal pathogens, the use of VAM as a biological cont=
rol agent to protect cabbage against several root diseases is suggested.

                                             ------------------------------=
----------------------------------------

Best Regards,

Thomas Giannou
http://www.tandjenterprises.com

  ----- Original Message -----
  From: soilfoodweb_at_aol.com
  To: compost_tea_at_yahoogroups.com
  Sent: Monday, November 01, 2004 11:55 AM
  Subject: Re: [compost_tea] Exudates (was: Re: Brassicas and vam fungi)


  It's clear we have a great deal more to learn.

  But it does seem clear that trying to grow a plant that needs mycorrhizal=
 fungi to suppress disease, or to obtain adequate nutrition AFTER you grow =
a brassica or cole or kale crop is not a wise idea.

  UNLESS you add back a mycorrhizal inoculum.

  But, you then have to make sure that you have done something to chew up t=
he exudates that the brassica may have produced, or the biology that the br=
assica may have produced.

  The easiest way to do that is to use compost or compost tea to establish =
the organisms, and chew up the toxic materials that might be there. Severa=
l applications are typically needed to establish the full diversity, becaus=
e the toxics kill lots of the critters with each application, until such ti=
me as the toxics are finally chewed up, and the foodweb can be established.=
  

  So start applying the compost or tea in the fall, so the soil is in shape=
 by spring.

  Elaine R. Ingham






Received on Mon Nov 01 2004 - 23:17:27 EST

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