Plant Physiology 72:66-70 (1983)
© 1983 American Society of Plant Biologists
Articles
Evaluation of the Water Potentials of Solutions of Polyethylene Glycol 8000 Both in the Absence and Presence of Other Solutes
Burlyn E. Michel
Department of Botany, University of Georgia, Athens, Georgia 30602
Published and additional data for polyethylene glycol 8000 (PEG), formerly PEG 6000, solution water potentials ( ) are compared. Actual bars over the concentration range of 0 to 0.8 gram PEG per gram H2O and temperature (T) range of 5 to 40°C are best predicted (probably within ± 5%) by this equation: = 1.29[PEG]2T 140[PEG]2 4.0[PEG]. Although transformable through division by [PEG] to virial equation form, results indicate that the coefficients are not virial. Mannitol (MAN) interacts with PEG to produce significantly lower than additive. Vapor pressure osmometer (VPO) data for MAN-PEG synergism compared favorably with those from thermocouple hygrometry; and VPO data showing the interactions between PEG and four salts are presented. The synergism of MAN-PEG and of NaCl-PEG are related linearly to the concentration of solute added with PEG.
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