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Old 06-12-2007, 12:34 PM posted to alt.binaries.pictures.orchids
John Varigos John Varigos is offline
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Default Tall Potato Orchid

Dave, I think you are right.

I recall having this discussion before where it was difficult to describe
what benefit the fungus got from what is obviously an unfair relationship.
So epiparasitic seems a more apt description of the relationship.

John


"Dave Gillingham" wrote in message
...
Sort of like the curate's egg - clearer in patches. Thanks, John. Was I
right
about the saprophytes having a mutually beneficial relationship? Or
should the
term saprophytic be wholly replaced by epiparasitic?

On Thu, 6 Dec 2007 16:30:14 +1100, "John Varigos"
wrote:

Hi Dave

Found this from a paper by Martin Bidartondo and others in Molecular
Ecology
(2001) 10, 2285–2295.

"Epiparasitic plants are nonphotosynthetic and they obtain fixed carbon
from
other plants via a shared mycorrhizal fungus. This behaviour makes them
cheaters of one of the most pervasive mutualisms in terrestrial
ecosystems.
There are several unique features of epiparasitic cheating that make it a
system likely to yield novel insights into symbiotic interactions.

First, epiparasitism involves a plant–fungal mutualism, whereas our
understanding of cheating is based on animal (almost exclusively insect)
interactions.

Second, the photosynthetic host does not interact directly with its
epiparasite. Thus, because there is no opportunity for the photosynthetic
host to select against its epiparasite without selecting against its own
mutualist, an ‘unholy alliance’ is forged between the epiparasitic plant
and
the mycorrhizal fungus.
Third, it is a system that combines an intimate interaction (i.e. one with
cell to cell contact) with a diffuse one (single fungi associated with
multiple plants and vice versa)."

Does that make it clearer? ;-)

John


"Dave Gillingham" wrote in message
. ..
The inflorescence just had that look about it.

I really don't know the difference between saprophytic & epiparasitic.
I
have
this feeling I've heard somewhere that a saprophytic relationship is
mutually
beneficial to the orchid & the fungus; whereas epiparasitic involves the
orchid
parasitising the fungus it relies on for nutrition, to the detriment of
the
fungus. Can anyone comment?

On Wed, 5 Dec 2007 20:41:37 +1100, "AusDigi" wrote:

One reference says its saprophytic while another says epiparasitic,
though
it doesn't mention the parasite it might be parasitizing.


"Dave Gillingham" wrote in message
m...
Would that be saprophytic, Reiner?

Dave Gillingham
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Dave Gillingham
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