Open AccessOxygen Availability in Polyethylene Glycol Solutions and Its Implications in Plant-Water Relations
Author(s) -
John G. Mexal,
James T. Fisher,
Janet Osteryoung,
C. P. P. Reid
Publication year - 1975
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.55.1.20
Subject(s) - polyethylene glycol , polyethylene , chemistry , oxygen , peg ratio , electrochemistry , electrode , organic chemistry , finance , economics
The solubility of O(2) in polyethylene glycol 4000 and 6000 solutions of varying concentrations was determined iodimetrically (titrimetrically) and electrochemically using a rotating glassy carbon electrode and a PAR Model 174 Polarograph. The titrimetric determination resulted in the formation of an unexpected precipitate at 2% (w/v) polyethylene glycol corresponding to the approximate critical micelle concentration of the two polyethylene glycol homologs. Beyond 5% polyethylene glycol, O(2) concentration was inversely proportional to polyethylene glycol concentration, and was higher in polyethylene glycol 4000 solutions than in polyethylene glycol 6000. The electrochemical data are a direct measure of O(2) transport to the electrode surface, rather than O(2) activity or concentration. Results indicate that even at relatively high H(2)O potentials, the transport of O(2) to the root surface might be insufficient to meet the plant's respiratory requirements.