Habituation in sugarbeet callus: auxin content, auxin protectors, peroxidase pattern and inhibitors

A GC‐ECD titration of IAA in normal auxin (2,4‐D)‐requiring and auxin‐independent (habituated) sugarbeet callus revealed an equal amount in both tissues. A comparison of the content and pattern (through starch gel electrophoresis) of soluble, membrane and wall peroxidases indicated that normal tissues contained a higher level of isoperoxidases. Normal tissues also were found to contain higher levels of peroxidase inhibitors and auxin protectors. The hypothesized peroxidase‐mediated higher rate of auxin destruction in normal sugarbeet callus is supposed to be counterbalanced by the 2,4‐D‐controlled auxin protectors.