Today was an unusual day in the Boston area near 70 F. It was so pleasant
that I decided to work in the yard, taking out an old concord grape vine.
I cut the vine about two feet up from the base (where it was almost 2
inches across) and spent the next 20 minutes cutting up the vine. I was
very surprised when I returned to the base and found a clear gel extruding
from the cut surface. These were 1/4 inch ribbons and fingers curling up
from the surface. Upon further investigation I also saw the extrusions on
some of the larger (1/2 inch dia) vine segments. Half way between pith and
bark seemed to the predominant extrusion area. My question is what is in
the xylem sap that is turning it into a gel, and what is causing it to be
extruded? Since in the spring this vine, when trimmed in the past,
produced an annoying drip, I assume this is a winter phenomenon, some sort
of plant antifreeze? Part of my master's work was analysis of western
hemlock xylem sap for cytokinins, and I never saw sap like that. Perhaps
grapes are special in this regard?
-John
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John Morris
Dept of Molecular Biology
Wellman Floor Eleven
Massachusetts General Hospital
Boston MA 02114
email: john.morris at molbio.mgh.harvard.edu
