Physical State of Water in Plant Xylem Vessels

Cary, J.W. and Jensen, M.E. and Fisher, H.D. (1968) Physical State of Water in Plant Xylem Vessels. Agronomy Journal. 60(2):167-169.

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Abstract

The vapor pressure psychrometer was used as a tool
to study the physical state of water in plant xylem vessels.
The experimental procedure involved measuring
the change in diffusion pressure deficit (DPD) of corn
and tomato plants when the stem was cut. When the
DPD was greater than 4 bars in tomatoes and 28 bars
in corn, the water in xylem vessels no longer appeared
to flow in response to hydrostatic pressure gradients. The
limiting value of DPD increased as the xylem radius
decreased. A mechanism is suggested which describes the
physical state and the movement of water through xylem
tissue under high DPD. The proposal is based on the
pressure difference across a curved air-water interface
and on the concept of an electrostatic double layer with
its associated osmotic pressure.

Item Type:	Article
NWISRL Publication Number:	0080
Subjects:	Mass Import - unclassified
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:53
Last Modified:	15 Mar 2017 22:13
Item ID:	601
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/601