Re: how do water move up in tree? what is driving force?
Benj
Andrew K Fletcher wrote:
> Basic theory behind the experiment which caused water to flow 24 metres up a
> cliff in Brixham, Devon.
> http://www3.sympatico.ca/slavek.krepelka/exper/ScienceRevw.htm
> [Hemet]
> Hi Andrew :-)
> You have the honor of being a true scientist and experimentalist. Yet
> you have to answer for some big questions.
I agree with Hemet that the theory is not correct.
One other thing that it does not explain is how plants have CONTROL
over water pumping. Wilting and restoration can be stimulated
electrically!
I think there are a few hints to this long-time question, but I have
never done enough work to generate a bone fide theory about it.
Basically I believe that somehow water pumping in plants is an
electrical phenomena. (See some of the great work by Prof Bose in his
old book) My idea is that there is a REQUIREMENT that sap contain
dissolved chemicals because pure distilled water would not be
conductive enough nor polar enough to be electrically pumped.
If you examine Xylems (tubes through which sap rises) you find very
interesting structures. There are cell membranes that exist between a
spiral thread of cellulose (insulator) creating a spiral membrane
rising up the tube. I suggest (but have not established) that an
action potential may travel this membrane such that it creates a
pumping action for the fluid in the tube. This action would be
similar to the action found in nerves in animals but has a pumping
function in plants. Such would explain Bose's electrical reversal of
wilting. Also it is already known that tall plants have valves in the
xylems which usually do not require sap to be pumped more than a few
feet.
Just some "new theory" food for thought!
Benj
Andrew K Fletcher
"Benj" <bja...@iwaynet.net> wrote in message
news:1188672601....@r34g2000hsd.googlegroups.com...
Andrew K Fletcher wrote:
Basic theory behind the experiment which caused water to flow 24 metres up
a
cliff in Brixham, Devon.
http://www3.sympatico.ca/slavek.krepelka/exper/ScienceRevw.htm
[Hemet]
Hi Andrew :-)
You have the honor of being a true scientist and experimentalist. Yet
you have to answer for some big questions.
I agree with Hemet that the theory is not correct.
One other thing that it does not explain is how plants have CONTROL
over water pumping. Wilting and restoration can be stimulated
electrically!
To disagree with this theory is to suggest a mechanism for evaporation that
does not have any effect on the density of residual fluids inside the tree.
Please elaborate as I find this impossible to understand. If we can agree on
density changes due to evaporationin transpiring leaves then the rest of the
theory is correct also.
Andrew
Hemet also asked me to answer Strasburger's results, Which I have done, and
will add after you have addressed this question at hand.
Benj
Andrew K Fletcher wrote:
>
> To disagree with this theory is to suggest a mechanism for evaporation that
> does not have any effect on the density of residual fluids inside the tree.
> Please elaborate as I find this impossible to understand. If we can agree on
> theory is correct also.
Yes. That is a very interesting point. What I suggested implies that
the chemicals in the sap are transported up the tree by the "pumping
mechanism" which clearly raises the question of why does not the
materials in the sap concentrate at the top of the tree as water
evaporates from the leaves? Good point. I'm not sure what the answer
is! Clearly most plants have various chemicals of various kinds in
the sap. I do not believe there is any evidence that pure water is
pumped up plant stems. I'm not sure what kind of "pumping mechanism"
would pump just the water leaving the chemicals in place. I do presume
that a tree for example has a much larger area (volume) for storing
liquid at the leaves and perhaps processes in the leaves somehow use
the chemicals transported in the sap. But this is all speculation on
my part. I'm not an expert in plant physiology.
Father Haskell
wrote:
> "Benj" <bjac...@iwaynet.net> wrote in message
>
> news:1188672601....@r34g2000hsd.googlegroups.com...
>
> Andrew K Fletcher wrote:
> Basic theory behind the experiment which caused water to flow 24 metres up
> a
> cliff in Brixham, Devon.
> http://www3.sympatico.ca/slavek.krepelka/exper/ScienceRevw.htm
> [Hemet]
> Hi Andrew :-)
> You have the honor of being a true scientist and experimentalist. Yet
> you have to answer for some big questions.
>
> I agree with Hemet that the theory is not correct.
> One other thing that it does not explain is how plants have CONTROL
> over water pumping. Wilting and restoration can be stimulated
> electrically!
How do you do this? Sounds like it has great prank potential.