Translocation and Metabolism of Endosperm-Applied [2-C] Indoleacetic Acid in Etiolated Avena sativa L. Seedlings

The role of free indole-3-acetic acid (IAA) in the endosperm of Avena sativa L. seedlings was investigated to determine its contribution to free IAA in the shoot. 2-¹⁴C]IAA was injected into the endosperm of darkgrown seedlings and the transport and metabolism of the ¹⁴C]-labeled compounds determined. It was concluded that translocation of free IAA directly from the endosperm is probably not a significant source of free IAA in the shoot, mainly because even small amounts of ¹⁴C]IAA introduced into the endosperm were rapidly metabolized. This suggested that, in Avena, free IAA does not normally exist in the liquid endosperm.