Fwd: Re: Mycorrhiza

Mark Spiro spiro at bucknell.edu
Mon May 7 09:54:24 EST 2001

It is my understanding that the endomycorrhizae, known as Vessicular 
Arbuscular Mycorhhizae (VAM), have very little host specificity.  In other 
words, they will form symbiotic associations with many species of plants, 
across family order and even class divisions.  It is beleived that VAM are 
very ancient symbiotic relationships as they are found in bryophytes, and 
pteridophytes.  This is exactly the opposite of the rhizobium root nodules, 
which in some cases is extremely species specific and with a few exceptions 
is found only in the legume family (Fabaceae).

I don't think that you have to worry about introduction of mycorrhizae as 
they are ubiquitous.  In studies where they compare the growth rate of 
infected and uninfected plants, the researchers have to go to great lengths 
(e.g. gamma irradiation) to get rid of the fungus from the soil in order to 
grow non-infected plants.

At 06:12 PM 5/5/01 +0100, you wrote:
>There are thousands of species of mycorrhiza that interact in species 
>specific ways with over 90% of the plants on the planet, providing 
>nutrients (often phosphorus) in exchange for carbon from the plant.  They 
>do aid in the growth of plants, but it's got to be the species that 
>interacts with the plants you want to grow.

Mark D. Spiro
Department of Biology
Bucknell University
Lewisburg, PA 17837
spiro at bucknell.edu
phone:  (570) 577-3486
fax: (570) 577-3537


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