Article,
Circulation of water within wheat grain revealed by nuclear magnetic resonance micro-imaging
Nature, 336 (6197): 399--402 (1988)
Abstract
Observation of water movement in situ is difficult and very few methods
are available for measuring directly the motion of water. Movement
of solutes or suspended particles is not a reliable guide and the
use of radioactive or heavy water is limited to a few applications.
Thus, although much has been inferred about the mechanism of water
movement through comparatively lengthy pathways1, less is known for
the shorter and more tortuous pathways within and between cells.
Still more challenging is the investigation of water motion within
structurally complex organs of small dimensions such as the fruits
and seeds of plants, some of which behave (for water) as practically
closed systems. We have observed longitudinally oriented bulk flow
of water in developing grains of wheat using a pulsed gradient spin
echo nuclear magnetic resonance technique combined with microscale
imaging. Movement of water is associated with import of nutrients
by the grain but is on too large a scale to be due to phloem transport
alone. The flow observed could be associated with unloading and/or
transport of nutrients in the vicinity of the vascular system. This
is the first report of the observation in vivo of water movement
on a sub-millimetre scale by non-invasive methods in any biological
system. � 1988 Nature Publishing Group.
