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RESEARCH INTERESTS
Plant organismal structure and function; water relations
Structure and function of plants, with an emphasis on adaptations to environmental stress
Plant water relations and stomatal responses to drought
hydraulic architecture of plants
Long distance water transport in plants and soil
Causes and consequences of xylem cavitation
PUBLICATIONS
Posters
Predicting plant water use from plant and soil properties
Theory vs. theory: can the cohesion theory survive?
Plant Structure and Function, Water Relations,
and Ecophysiology.
My interests lie in the physiological and structural
adaptations of plants. A long-standing focus has been on
water relations. The balance of water supply and demand
in plants has direct links to their photosynthetic
potential and adaptation to environment. My research
emphasizes the water uptake and transport process
because it has given new insights into the adaptive
significance of stomatal regulation and the mechanisms
underlying drought and freezing adaptation. There are
well-defined biophysical limits on water uptake caused
in part by xylem cavitation and rhizosphere processes
which have their basis in plant structure. These limits on
water uptake set stomatal limits on water loss and
photosynthesis. Differences in drought tolerance, root
distribution, vegetative phenology, and stomatal behavior
between taxa correspond closely with water uptake
limits. We have studied the coordination between water
uptake capacity and water loss regulation in a variety of
species and circumstances ranging from mangroves to
deserts to boreal forest. Current projects in the lab
include: a comparative study of water uptake and drought
tolerance in Great Basin shrubs of Utah, stomatal
responses to leaf water status and hydraulic
conductance, modeling biophysical limits on plant water
flux, susceptibility to freezing-induced cavitation,
hydraulic vs. mechanic consequences of wood structure,
and allometry of plant vasculature.
Selected Publications
Jackson, R.B., J.S. Sperry and T.E. Dawson. 2000. Root
water uptake and transport: using physiological
processes in global predictions. Invited review. Trends
in Plant Science (in press).
Hacke, U.G., J.S. Sperry, B.E. Ewers, D.S. Ellsworth, K.V.R.
Schäfer and R. Oren. 2000. Influence of soil porosity on
water use in Pinus taeda. Oecologia, (in press).
Pockman, W.T. and J.S. Sperry. 2000. Vulnerability to
cavitation and the distribution of Sonoran Desert
vegetation. American Journal of Botany (in press).
Sperry, J.S. 2000. Hydraulic constraints on plant gas
exchange. Agricultural and Forest Meterology
2831:1-11.
Oren, R., J.S. Sperry, C.G. Katul, D.E. Pataki, B.E. Ewers, N.
Phillips and K.V.R. Schäfer. 1999. Survey and synthesis
of intra- and interspecific variation in stomatal
sensitivity to vapour pressure deficit. Plant Cell and
Environment 22:1515-1526.
Kolb, K.J. and J.S Sperry. 1999. Differences in drought
adaptation between subspecies of sagebrush
(Artemisia tridentata). Ecology
80:2373-2384.
Davis, S.D., J.S. Sperry and U.G. Hacke. 1999. The
relationship between xylem conduit diameter and
cavitation caused by freeze-thaw events. American
Journal of Botany 86:1367-1372.
Stiller, V. and J.S. Sperry. 1999. Canny's compensating
theory fails a test. American Journal of Botany
86:1082-1086.
Sperry, J.S., F.R. Adler, G.S. Campbell and J.C. Comstock.
1998. Limitation of plant water use by rhizosphere and
xylem conductances: results from a model. Plant Cell
and Environment 21:347-359.
Linton, M.J., J.S. Sperry and D.G. Williams. 1998. Limits
to water transport in Juniperus osteosperma and
Pinus edulis: implications for drought tolerance
and regulation of transpiration. Functional Ecology
12:906-911.
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