Ionic currents traversing cell clusters from carrot suspension cultures reveal perpetuation of morphogenetic potential as distinct from induction of embryogenesis.

Patterns of ionic currents accompanying shape and surface changes during growth of cell clusters from carrot suspension cultures were examined using a vibrating probe. Electrical polarity was established in clusters undergoing apparently disorganized proliferation in the presence of 2,4-dichlorophenoxyacetic acid (2,4-D). This electrical polarity is similar to that found in organized somatic embryos which form upon removal of 2,4-D, and implies that the proliferating clusters are actually suppressed embryos. This implication is further supported by observations using scanning electron microscopy. We conclude that the potential to undergo embryogenesis is present even before the 2,4-D is removed, but cannot be realized in the presence of the auxin.