Daily fluctuations in water potential and associated ionic changes in Atriplex canescens
Related Experiment Video
Updated: Mar 6, 2026

Measuring the Osmotic Water Permeability Coefficient Pf of Spherical Cells: Isolated Plant Protoplasts as an Example
Published on: October 8, 2014
Roger W Ruess1,2, Mohan K Wali1,2
1Department of Biology, University of North Dakota, 58202, Grand Forks, ND, USA.
Abstract:
Water potential (Ψ) measurements of Atriplex canescens at the base of the Red Desert near Tipton in Wyoming, revealed a range between-15.5 to-45.1 bars. Minimum values coincided with the lowest air and soil temperatures, maximum with the greatest atmospheric evaporative demand. Change in Ψ exceeded 12 bars h-1 during periods of rapidly moving storm systems. Changes in Ψ appeared to be independent of plant size, age, sex, and the spatial location of plants. Chemical analyses revealed that xylem sap was up to three times more concentrated at high than at low Ψ. It was observed that the flow rate of sap was greater at lower than at higher Ψ and that the increase in water movement accounted for the dilution of the baseline concentration of sap solutes. Together, Ca, Mg, K and Na contributed 58% of the mean osmolality of the xylem sap; the dominant ions, however, were K and Cl. We suggest that the ability of the species to respond rapidly to changing atmospheric conditions affords it a distinct advantage in a harsh environment.
More Related Videos
08:25BtM, a Low-cost Open-source Datalogger to Estimate the Water Content of Nonvascular Cryptogams
Published on: March 25, 2019
12:11Measurement of Leaf Hydraulic Conductance and Stomatal Conductance and Their Responses to Irradiance and Dehydration Using the Evaporative Flux Method EFM
Published on: December 31, 2012
Related Concept Videos
Tonicity in Plants
Tonicity in Plants
Tonicity
Tonicity describes the capacity of a cell to lose or gain water depending on the solute...
Responses to Salt Stress
Adaptations that Reduce Water Loss
Tonicity in Animals
Tonicity in Animals