Loss of rubidium and potassium from barley roots on sudden chilling.

Sudden chilling of roots of barley pretreated in a labeled Rb(+) solution at 25 C causes a transient loss of label from the nonfree space. The half-time of the release is about 10 minutes. Within the first few hours of uptake the loss increases proportionally to the root Rb(+) content but varies between experiments as a fraction of this content: values from 4 to 20% were observed. The same phenomenon is found for K(+) labeled with (86)Rb(+).