The roots would not survive. There is no circulatory system~as you state.
However there is a two way passage. From the roots water and nutrients to
all parts and then complex 'foods' manufactured by the leaves also to
everywhere including the roots so they can survive and grow.
Water travels via the woody parts [xylem] and food via the phloem in the
bark. This is why ring-barking will kill a tree relatively quickly.
Best Wishes
"Bruce W.1" wrote in message
news:LtF6c.9871$F91.6868@lakeread05...
Please correct me if I'm wrong, and I probably am wrong.

Plants don't have a circulatory system. There is no circulatory loop
like with mammal blood. All moisture goes from the roots up. This is
caused by moisture evaporation from the leaves.

Theorhetically then, you could chop off a plant at ground level and
connect the stem to a vacuum suction pump and the roots wouldn't know
the difference, the roots would continue to grow.

What's wrong with this theory? Or might it actually work? If not then
why?

Thanks for your help.