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quote:Now I wonder where the idea of sugars causing what is believed to be osmotic pressure, originated?
quote:You give the impression of not thinking that osmosis has any effect... and of doubting whether it exists.
quote:Originally posted by daveshortsI don't see why the bulk flow rates are not possible by osmosis - the rate of osmosis may be slow per unit area - but there are a huge number of xylem and their suface area is huge - so it all adds up to a big number - unless you can do soame maths to back up your argument it isn't very strong...You didn't get my point about the Phloem - if it is all at an absolute positive pressure, if you wired one into the Xylem, theere would be flow of sugars into the xylem as the pressure is bigger there - THE WRONG WAY - so if this is the case your theory can't use the Phloem as the downward path (especially as sugars flow up or down a tree depending on the season....) - and I don't think there is anything else to use
quote:Science is now conducted by professional scientists, it's the 21st century. The time of the "Gentleman Scientist" is behind us, it's a concept I have some affection for, but will never be re-instated.
quote:Everyone in this forum is trying to help but you are at a considerable evolutionary disadvantage. It remains possible for the Gentleman Scientist to publish, but you simply must research others work and communicate in the right way. It's our rules now. Alternatively you can withdraw from competition, which is ultimately the safer thing to do.
quote:It's our rules now
quote:I remain true to my original offer, and make a second. If you are minded to look into other people's publications in the area, I will give you a list of journal articles that may get you started.
quote:What I do find surprising is that no one here appears to have conducted the experiments for themselves in order to give a qualified account of their own observations. If it is the money, I will send the £3.00 so that you can purchase the tubing and T junctions.
quote:If you were to place an atomiser from a paint spray gun at the top of the tree, under say 65 psi, would you really expect this to cause water to be drawn up the tubes inside the tree?
quote:I am also surprised that the link below did not generate much interest?http://www-saps.plantsci.cam.ac.uk/search_links.htm [Links inactive - To make links active and clickable, login or click here to register]
quote:Why is it that the phloem sap is observed to flow down, in the opposite direction to the predicted path of suction generated by the leaves?
quote: If you were to place an atomiser from a paint spray gun at the top of the tree, under say 65 psi, would you really expect this to cause water to be drawn up the tubes inside the tree?
quote:For you to keep dismissing this as irrelevant to trees, without observing the hard evidence for yourself is a reaction I have grown to expect from people who would rather believe text in text books, than to question and evaluate the theories for themselves. You have absolutely no idea of the full implications. I have lived and loved my work and will do so until the day I die!
quote:The most important question I have to you despite all this, is have you ever considered that you may be wrong? or prefereably tried to proove yourself wrong. As if you haven't you are not doing science but PR.
quote:I believe you will find that the negative tension inside the inverted U tube at 20 metres will be far higher than your estimate.
quote:Atmospheric pressure will support a 10m column of water. This will give a vacuum pressure above the water (0Atm) We know that. (I think?)
quote:When the water level goes below the 10 M level in the Barometer type experiment, it is then supported by a vacuum.
quote:In the Inverted U tube experiment, there is twice the weight applied to the column of water suspended over the raised middle of the tube, and therefore twice the amount of tension is applied to the water inside the tube, yet it remains relatively stable providing the gas has been removed from the water by pre-boiling it.
quote:Strousburger already did it by killing the tree and observing water transpiring from the leaves for three weeks
quote:What would you, or anyone else reading this expect to happen to the water in the end exposed to the atmosphere via the U shaped exit point, and the central T junction was elevated to 2 metres vertical?
quote:A simple thought experiment for you to consider Imagine the inverted U tube experiment set up, but this time, the two open ends are submerged in one sealed container, with the water level afording some air space above it. And it has all the pressure removed eliminating any positive pressure or influence from the atmosphere.
quote:Prediction, the water column will remain intact. What do you think? B.T.W thinking about a way of testing this one to settle an argument.
quote:In the case of the barometer type experiment, "Thought experiment again unfortunately" removing the poitive pressure in this experiment by sucking the air out of the beaker containing the water with the open end of the capped water filled tube will indeed cause the water to be pulled from the top of the capped tube at a much lower height than ten metres. But this does not prove that the pressure was the only force supporting it. It suggests that the increased downward force of the water has severed the hydrogen bonds to the capped glass tube.
quote:I was trying to refer to the way a syringe pulls water up, even when there is air space directly in front of the plunger. The absence of pressure if you like is sufficient to draw water up acting upon its surface, so why do you think the vacuum is any different to the suction caused by the plunger in a syringe?
Quote from: rosy on 26/05/2005 22:09:16Andrew, I hope I'm about to explain some things you already know. But it's not at all clear from your posts that you do understand this stuff.Up to 10m, nothing has to be supported under tension *at all* because it's all happening at positive pressure.
Andrew, I hope I'm about to explain some things you already know. But it's not at all clear from your posts that you do understand this stuff.Up to 10m, nothing has to be supported under tension *at all* because it's all happening at positive pressure.