IAA Metabolism in Embryogenic and Non-Embryogenic Carrot Cells

Carrot somatic embryos can readily be induced from embryogeniccells transferred from auxin-containing medium to auxin-freemedium, but not from transferred non-embryogenic cells. It iswell-known that IAA, a natural auxin, plays important rolesin many physiological responses including somatic embryogenesis,but, there is no report of the IAA metabolism in embryogenicand non-embryogenic cells. Therefore, we examined IAA metabolismin embryogenic and nonembryogenic carrot cells. In this paper the IAA metabolism in embryogenic cells and non-embryogeniccells is described. The induction of IAAsp formation was clarifiedin both cells. On the other hand, in non-embryogenic cells,an unknown metabolite was detected and identified as oxindole-3-acetylasparticacid (oxIAAsp). OxIAAsp formation may be induced to eliminateexcess auxin. Furthermore, endogenous IAA contents in both cellswere quantified and the relationship between somatic embryogenesisand IAA metabolism is discussed. (Received May 2, 1994; Accepted August 30, 1994)