Brooklyn1 wrote:
On Sat, 25 Aug 2012 08:18:38 +1000, "David Hare-Scott"
wrote:

Brooklyn1 wrote:
"David E. Ross" wrote:

If you really want to kill the ivy, apply Roundup to the foliage
with a sponge or brush, which will avoid damaging the tree on which
it is growing.

That's much too risky. The ivy will quickly draw the Roundup deep
into it's roots where it will be deposited in close proximity to the
tree roots, whereby it will severely damage if not kill the tree.

How do you know this?

The same way most folks who possess common sense know such things,
from experience. I've personally done exactly what you propose to an
old wisteria vine growing too close to my back garage door and a short
time later noticed the leaves on my holly bush growing on the other
side of the fence were shriveling. So how many times did your mommy
have to tell you the stove is hot before you burned yourself...

As well as my mum telling me about stoves my dad told me "The problem with
people is not so much the things they don't know but the things they know
that just ain't so" I believe that is from Mark Twain. Your proposed root
to root transfer mechanism seems to be an assumption to me with no direct
evidence. It may be right or wrong, I don't know. Don't take it personally
I am not saying this to wind you up but to get to a good answer.

David

In article ,
"David Hare-Scott" wrote:

Brooklyn1 wrote:
On Sat, 25 Aug 2012 08:18:38 +1000, "David Hare-Scott"
wrote:

Brooklyn1 wrote:
"David E. Ross" wrote:

If you really want to kill the ivy, apply Roundup to the foliage
with a sponge or brush, which will avoid damaging the tree on which
it is growing.

That's much too risky. The ivy will quickly draw the Roundup deep
into it's roots where it will be deposited in close proximity to the
tree roots, whereby it will severely damage if not kill the tree.

How do you know this?

The same way most folks who possess common sense know such things,
from experience. I've personally done exactly what you propose to an
old wisteria vine growing too close to my back garage door and a short
time later noticed the leaves on my holly bush growing on the other
side of the fence were shriveling. So how many times did your mommy
have to tell you the stove is hot before you burned yourself...

As well as my mum telling me about stoves my dad told me "The problem with
people is not so much the things they don't know but the things they know
that just ain't so" I believe that is from Mark Twain. Your proposed root
to root transfer mechanism seems to be an assumption to me with no direct
evidence. It may be right or wrong, I don't know. Don't take it personally
I am not saying this to wind you up but to get to a good answer.

David

http://www.arborecology.co.uk/article_forf.htm
Ivy has a very bad reputation and it is commonly thought that it kills
trees. Contrary to popular belief, ivy is not parasitic and does not
directly affect the health of the trees it climbs. Unlike true parasitic
plants, (such as mistletoe, whose roots tap directly into the resources
of the host plant) ivy has its feeding roots anchored in the ground and
simply uses the tree as a support to get to where it wants to go. The
masses of tiny, hair-like roots sprouting from the under surface of the
stems, are simply designed to provide support and allow the plant to
climb. Although these roots provide almost immovable adhesion to the
rough surfaces of tree trunks and walls, they are not used for feeding,
and at worst only penetrate the outermost layer of bark on host trees.

It is primarily in terms of competition for natural resources that ivy
affects the health of trees, particularly where light is concerned. If
ivy has become established on a tree, it is more likely to be a sign of
stress than a cause of it. A heavy infestation of ivy, particularly in
the upper crown, is usually an indication that the tree is in a natural
state of decline; most healthy crowns will let insufficient light
through for the ivy to grow vigorously. Ash, Fraxinus excelsior, is an
exception as the crown tends to be thin and open. This allows major
infestations to occur, thereby restricting photosynthesis, but it is
still unlikely that the life of a healthy tree will be shortened. In the
case of a diseased or dying tree, where the it¹s growth rate and vigour
may be slow or in decline, the ivy¹s more vigorous growth allow it to
smother the tree. The bushy adult growth will then have a tendency to
make the tree top heavy, making it more likely to fall, particularly
during adverse weather conditions.

http://pep.wsu.edu/hortsense/scripts...?tableName=Wee
d&categoryID=6&problemID=2057
While it is not parasitic, the dense ivy canopy may contribute to wind
damage of trees because it catches the wind and creates a "sail" effect.

http://aggie-horticulture.tamu.edu/a...v/groundco.htm
l
English Ivy is just climbing on and attaching to the tree with aerial
roots which do not penetrate the tree and "suck or feed on" the life
blood of the tree -- English Ivy IS NOT parasitic.
-------

Then glyphosate functions by occupying the binding site of the
phosphoenolpyruvate. It isn't excreted.

When glyphosate comes into contact with the soil, it can be rapidly
bound to soil particles and be inactivated.[39] Unbound glyphosate can
be degraded by bacteria.[78] It has been proposed that glyphosate
applications increase the infection rate of wheat by fusarium head
blight.[79]

In soils, half-lives vary from as little as three days at a site in
Texas to 141 days at a site in Iowa.[80] In addition, the glyphosate
metabolite aminomethylphosphonic acid has been found in Swedish forest
soils up to two years after a glyphosate application.[81] Glyphosate
adsorption to soil varies depending on the kind of soil.[82]
https://en.wikipedia.org/wiki/Glyphosate


Glyphosate adsorbs strongly to soil and is not expected to move
vertically below the six inch soil layer; residues are expected to be
immobile in soil. Glyphosate is readily degraded by soil microbes to
AMPA, which is degraded to carbon dioxide. Glyphosate and AMPA are not
likely to move to ground water due to their strong adsorptive
characteristics.

EPA Reregistration Eligibility Decision (RED)
0178fact.pdf


Glyphosate is a chelating agent.

--
Welcome to the New America.
http://www.youtube.com/watch?v=hA736oK9FPg
or
E Pluribus Unum
Green Party Nominee Jill Stein & Running Mate, Cheri Honkala
http://www.democracynow.org/2012/7/13/green_party_nominee_jill_stein_running

David Hare-Scott wrote:
....
I have to say to start I don't know the answer and I am asking questions to
try to work one out. The reason I doubt the crossover from root to root
idea is that glyphosate is said to be quickly deactivated in contact with
the soil so it seems a bit much for it to cross two membranes and the soil
and arrive intact. The idea that ivy draws on the fluids from its host
seems a more promising mechanism to me. If anybody has any references to
that I would like to read them.

no actual references beyond general biology texts
which do show that fungal hyphae can move nutrients
around between plants or from the soil into plants
(they do act as a phosphate transport).


songbird

In article ,
songbird wrote:

David Hare-Scott wrote:
...
I have to say to start I don't know the answer and I am asking questions to
try to work one out. The reason I doubt the crossover from root to root
idea is that glyphosate is said to be quickly deactivated in contact with
the soil so it seems a bit much for it to cross two membranes and the soil
and arrive intact. The idea that ivy draws on the fluids from its host
seems a more promising mechanism to me. If anybody has any references to
that I would like to read them.

no actual references beyond general biology texts
which do show that fungal hyphae can move nutrients
around between plants or from the soil into plants
(they do act as a phosphate transport).


songbird

The glyphosate bonds to the enzyme 5-enolpyruvylshikimate-3-phosphate
synthase (EPSPS).

X-ray crystallographic studies of glyphosate and EPSPS show that
glyphosate functions by occupying the binding site of the
phosphoenolpyruvate (which would normally bonding at this site),
mimicking an intermediate state of the ternary enzyme substrates complex.

As you can see
https://en.wikipedia.org/wiki/Arbuscular_mycorrhizae
AM fungi (AMF) help plants to capture nutrients such as phosphorus,
sulfur, nitrogen and micronutrients from the soil.

https://en.wikipedia.org/wiki/Glyphosate
As you can see glyphosate is a much larger molecule than the nutrients,
and there is no reason to suppose that the mycorrhizae could transport a
molecule as large as glyphosate.

--
Welcome to the New America.
http://www.youtube.com/watch?v=hA736oK9FPg
or
E Pluribus Unum
Green Party Nominee Jill Stein & Running Mate, Cheri Honkala
http://www.democracynow.org/2012/7/13/green_party_nominee_jill_stein_running