Is capillarity anti-gravity?

[Christophe]

I know well the principle of the ram I mounted one ...

Where is the loss of sap flow in the case of a plant? Where's the hydraulic shock?

Maybe it is played at the cellular level?

[plasmanu]

That's the mystery, where is the ram in the root. A sheep is much bigger than a small piece of wood. But the nitrogen bags some roots have, and some plants expel their seeds very far

[Christophe]

Re explain a little why and where is the mystery?

Why would the vegetal capillarity be limited to 1 m "without mystery"?

[Ahmed]

To reach the top of the trees, an astonishing performance, it is necessary to use several joint mechanisms. The root pressure results from the difference in concentration between the medium and that, higher from the root: it is this osmotic phenomenon which allows the extraction of water. Capillarity and evaporation complete the action ... This remains surprisingly effective, even if the process is slow (but voluminously important).

[Christophe]

This remains surprisingly effective, even if the process is slow (but voluminously important).

And therefore exploiting this phenomenon could feed a machine ... slow but powerful!

What is the flow (say in L per day?) Of sap from a medium tree? Do we have an idea?

Let's say a leafy tree 50 cm in diameter at the base?
Same question for a conifer of the same trunk size?

[izentrop]

It is a force in any case. A force which can raise the sap by 2 m in a capillary which is the xylem of a tree. Another more important force and the osmosis at the level of the capillaries of Racine, which can raise the sap of approximately 20 meters. Another even more important force is evapotranspiration, which can raise the sap to 120 m at the end of the leaves.

https://odpf.org/images/archives_docs/1 ... emoire.pdf

memory.pdf

(1.01 million) Downloaded times 888

[Christophe]

Correct answer Izi!

Do you take care of the equation?

I see that some equations of .pdf are bugged (??? instead of symbols ) ... In any case it is quite a memory for a high school level! Waaaw!

[Exnihiloest]

The water rises by capillarity because of the different surface tensions between the wet lower parts, and the top, still dry. Once the water is at the top, the process stops (the water cannot escape at the top and fall back down, some clever people have tried it to make a perpetual movement. At the top the force of adhesion to the wall retains water).
With evaporation, there is an energy supply and the system can loop. But there are better ways to use evaporation, for much more spectacular movements, but unfortunately still far too weak to provide useful energy:

[Christophe]

Yes Yes Yes...

But I want equations now!

[plasmanu]

Re explain a little why and where is the mystery?

Why would the vegetal capillarity be limited to 1 m "without mystery"?

In a German scientific report on Arte.
Everything was there, memory of water stress, root osmosis, evapotranspiration, excess water + CO2 = sugar + O2
Back to the roots. Winter storage.
It is the rise of sap (out of the vegetative state) after the frosts which annoyed them before evapotranspiration. I remember the number 1 in meters, and that it strongly depletes the plant: so something important is going on.

It must be lying on www.arte.tv it's a bible this chain