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Springfield, MO

Long post (sorry), but read through it and see what you think:

Water (carrying nutrients) moves through the plant's vascular system into the pumpkin. How? Why does the fluid go into the pumpkin?

Is the pumpkin a negative pressure sink, i.e. does it "suck" the fluid? Or is the water "pushed" into the pumpkin by some positive force within the plant? What is the "engine" that drives this motion? What steers the fluid in one direction or another, i.e. "into" versus "out of" the pumpkin?

One reason for the questions: When I have cut the vines to my pumpkins at harvest and placed them in gallon jugs of water they never take up much (if any water). I wonder if that is because I "broke the vacuum" suction of the system when I cut the vine.

Observations: Fluid leaks from vines when cut, but usually more on the "plant side" of the cut than on the "pumpkin side" of the cut. Fluid leaks from the top of a root still in the ground if one is severed at ground level (and may continue for several days, actually!).

Theory: The roots are the engine "magically" driving fluid into the plant's vascular system, creating a positive-pressure system. Therefore, without this positive pressure in the cut vine the pumpkin will not take up much (if any) fluid. Therefore, there is little to gain by placing the cut ends of the vines in water.

Alternative theory: Despite positive pressure from the root uptake of fluid, the pumpkin also "sucks." When the vacuum within the vascular space is broken by cutting the vine, air enters the vascular system and "re-pressurizes" it. Therefore, if a vine was cut under water and placed into water jugs under water, the pumpkin would continue to take up fluid at (or near) the rate that it was prior to the vine being cut.

What do you think?

9/5/2004 6:59:11 PM

Ohio

Dr,
Someone ought to try that when they take there pumpkin to the fair, completly sumerge the vine down into a 5 gallon bucket of water and cut it while its under water with out letting the vine get any air. It might work, it might even keep growing for a day or so, never know, but thats a good thinking.

9/5/2004 7:59:19 PM

[email protected]

Water enters roots by osmosis where the accumulated salts in the root system "pull" water into the root from the less salty soil solution.

Water & nutrients that go alononmg for the ridt then head to the leaves where photosynthesis takes place. The result is wtaer now laden with starches & carbohydrates. And this is where things get confusing.

Good reading on this website was the idle ramblings of this past winter posed by Joze. Search the word "SINK" for Joe's theories of the Sinek/Source relationship.

There are hormonal influences that we know are at work which regulate & trigger the movement & destination of the photosynthate. The presance (or lack of) seeds & the resulting giberellins plays a role in this game of push/pull.

To what extent? I have no idea. LOL

Steve

9/5/2004 9:13:24 PM

Pulaski Tn [email protected]

mine do!!

9/6/2004 9:20:54 AM

Edmonton, Canada

lol!!!

9/6/2004 10:44:31 AM

Springfield, MO

Tremor -- interesting post. Thanks for the food for though. I'll have to look up that old thread to add to my own mental 'ramblings' :-)

hey, I keep trying to reach you by phone...will you be around on Tuesday? If so drop me an email with the best time to call and I will try to do it then...my schedule is wide-open tomorrow. -- Chris

9/6/2004 4:15:05 PM