Sso. Burgess et al., Seasonal water acquisition and redistribution in the Australian woody phreatophyte, Banksia prionotes, ANN BOTANY, 85(2), 2000, pp. 215-224
Sap flows in the xylem of plant roots in response to gradients in water pot
ential, either between soil and atmosphere (transpiration) or soil layers o
f different moisture content (termed hydraulic redistribution). The latter
has the potential to influence water budgets and species interactions, but
we lack information for all but a Few plant communities. We combined heat p
ulse measurements of sap flow with dye and isotope tracing techniques to ga
uge the movement of xylem sap within, and exudation from, roots of Banksia
prionotes (Lindley). We demonstrated 'hydraulic lift' during the dry season
and provide some evidence that extremely dry soils limit hydraulic lift. I
n addition we report difficulties posed by spiralled xylem tissue in roots
for the application of heat pulse techniques. (C) 2000 Annals of Botany Com
pany.