Re: Mycorrhiza: questions

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Abgeschickt von Darcy Gunnlaugson am 08 August, 2000 um 05:06:44

Antwort auf: Mycorrhiza: questions von Luke Kiger am 06 August, 2000 um 18:32:44:

Hi Luke;

You wrote:

#1 Is the mycorrizae that must be present to facilitate germanation remain active in the plants root system after germination?

It has been absolutely determined (Steele, Whitlow, Werner, etc.) that the mycorrizae is not necessary for germination in (labratory) sterile trials. Nutrient rich mediums preclude the necessity for the symbiont, and bleach treatment proir to seeding, softens the seedcoat so that penetration of it by the fungus to establish the initial symbiotic realtionship, is not required.

#2 If so does it remain an active part of the plants food synthesis process?

In the labratory trials, no. But in nature the symbiotic relationship seems to remain lifelong, and although not a requirement, I have found that plants with this relationship intact, seem to be more vigourous and healthy. LAbratory plants planted out in a bed where the fungus is availbale, do much better than those grown in totally artificial mediums. However, a fungus can actually invade the root system of a weak plant beyond it's normal limits and kill it, so there is down side to it as well.

I do know that in some species of terrestrial orchids that this is a fact and if the mycorrizae is disturbed the host plant will often die. In the species Goodyera for example it is present through out the live cycle of the plant but the plant does not seem to be to bothered with out it.

The same is true of Cypripedium.

If you can point me in the direction of any research along these lines I would be most thankful.

You can try contacting members of this forum (Steele, Cribb, Werner, Whitlow, etc) at their addresses if interested in their research, but the above information is pretty much standard.