IAA-conjugate formation in carrot tissues transformed with aux-Ti plasmids was induced by exogenously applied IAA.When the tissues were treated with NAA or 2, 4-D, IAA-conjugate formation was also induced.This result suggests that IAA-conjugate formation may be generally induced by substances having auxin activity.On the other hand, 2, 4-D was not metabolized to conjugate form even when the transformed carrot tissues were treated with IAA.This suggests that the effect of 2, 4-D is different from that of IAA in carrot.