Further Comparisons between Carbowax 6000 and Mannitol as Suppressants of Cucumber Hypocotyl Elongation

Stirring largely eliminated the greater effectiveness of Carbowax 6000 compared to mannitol in reducing cucumber (Cucumis sativus L.) hypocotyl section elongation. Stirring increased elongation in water but reduced elongation in growth regulator solution. Shrinkage of cells without plasmolysis in hypertonic Carbowax solutions indicates that Carbowax 6000 did not penetrate cell walls. Sections prevented from elongating during pretreatment exposure to saturated air grew as much as those not pretreated. Sections pretreated with isotonic Carbowax responded similarly, but sections pretreated with isotonic mannitol grew less.