Talk:Ascent of sap

Do we need this page?
There is a page on Transpirational pull (redirect from cohesion-tension). Do we need a separate page on ascent of sap?Michaplot (talk) 16:43, 15 February 2010 (UTC)

I think that there is a need for this page because as even the Wikipedia page "Xylem", section "Cohesion-tension theory", admits, the cohesion-tension theory is subject to significant objections:
 * 1) One objection is that the theory is valid only for trees that are a few tens of meters tall, whereas eucalyptus trees can reach 100 meters tall and sequoias can reach 115 meters.
 * 2) Another objection is that if a hole is bored in a living tree's trunk, sap flows outward through the hole ; air and water do not flow inward ; hence the sap in the trunk is under positive, not negative, pressure.
 * 3) Furthermore, it's possible to cut halfway through a tree's trunk and to cut halfway through the trunk from the opposite direction but at a greater height, so that every tubule in the xylem is severed, yet the tree will survive.

Henri Gouin, a French professor of fluid dynamics, has proposed a theory of sap ascent in trees which proposes that sap ascends as a film covering the walls of the xylem tubules. The theory overcomes the above objections to the cohesion-tension theory. Gouin's theory is presented here — albeit not very well at present. VexorAbVikipædia (talk) 06:14, 31 July 2015 (UTC)


 * It feels like this page might deserve being merged into xylem article, which does a pretty in-depth job of covering theories. Notably that article does *not* link to this one, which is a pretty big sign that this page is not needed. --Nanite (talk) 07:11, 14 July 2020 (UTC)

Gouin's theory of sap ascent
This article contains a paragraph outlining a new theory of sap ascent which has been proposed by Henri Gouin, a French professor of fluid dynamics. The paragraph begins: "An alternative theory points out that liquids are at the walls submitted to intermolecular forces … ". This paragraph is copied almost word for word from the abstract of Gouin's paper of 2011, which is cited at the end of the paragraph. Unfortunately Gouin's English is imperfect and the paragraph does contain some jargon that isn't defined. Hence some editor wrote: "[clarification needed (opaque jargon which sounds made up)]". I intend to review Gouin's papers on this subject and then to provide a clearer account of his theory. VexorAbVikipædia (talk) 06:14, 31 July 2015 (UTC)
 * Good idea! I look forward to reading it.  Oreo Priest  talk 06:24, 10 August 2015 (UTC)

Section on Pohlé lift?
Does anyone have a better reference on an alternate theory that trees over the height of a one atmosphere column of water ( 10.3 m or 33.8 ft) use something analogous to an industrial technique called the Pohlé lift:


 * https://encyclopedia2.thefreedictionary.com/Pohl%C3%A9+air+lift+pump
 * https://patents.google.com/patent/US487639A/

The idea is the sap as actually an air-water mix such that the average density is, say, a tenth of that of water. I can't find a good reference though. Best I found are:


 * http://www.nodiggardener.co.uk/2016/10/how-does-water-get-to-top-of-large-tree.html

These articles are about microphones that let you listen the to bubbling (although they describe it a cavitation, not as Pohlé lift)
 * https://www.americanforests.org/blog/quiet-please-the-tree-is-speaking/
 * https://www.theashproject.org.uk/tree-listening-alex-metcalf/

Cohesion-tension (if it exist at all) couldn't occur in an air-water mix, can it?

Thoughts? Talk to SageGreenRider 19:19, 11 August 2020 (UTC)

WHICH ??
"The results of this modern-day experiment showed that there were no rhythmic electric oscillations present in the plant. Despite not being able to replicate the oscillations that Bose recorded, this study believes that the presence of sodium played a role in his findings." > What "this" modern day experiment?? what "this" study? the only study mentioned is Bose's! 2A02:3032:409:3451:1:1:4A8D:D2B8 (talk) 17:49, 25 July 2022 (UTC)