twambach at uoguelph.ca
Fri Feb 6 19:34:28 EST 1998
Do you know of any techniques used to quantify or compare plants'
responses to water stress other than the pressure bomb, psychrometer or
actual field experiments? I am planning to examine a cultivar (species yet
to be determined) classified as drought tolerant (relatively) and
compare it with an 'average/non-drought tolerant' control.
Another question that distantly, since simplified, relates to plants: what
are the forces acting on a pipe/tube when put vertically, its bottom
immersed in a tank of water and a pump attached on its top which is
powerful enough to raise a water-column through the pipe. It is assumed
that the weight of the pump is negligible and that the water supply is not
limiting. The latter point is important since I am particularly interested
in whether the pipe experiences any of the forces which cause the pipe to
collapse in the absence of water and significant 'suction' generated by
the pump. In other words: can the 'negative' pressure generated by the
pump be completely transferred onto the column? What about the weight of
the water column itself? Is the water completely 'held' by the pump in
such a case or do the lower parts of the pipe nonetheless experience an
outward pressure due to the weight of the water?
I'll appreciate any ideas.
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