Relationship between transport and metabolism of α-naphthaleneacetic acid, β-naphthaleneacetic acid and α-decalylacetic acid in segments of Coleus.

Transportand metabolism of α-naphthaleneacetic acid β-naphthaleneacetic acid, and α-decalylacetic acid, all labelled with (14)C in the carboxyl, group, were studied. Only α-naphthaleneacetic acid is transported in a polar way. Most of the radioactivity in the tissue is in a low molecular form, either free or as immobilization products. The immobilization of β-naphthaleneacetic acid is similar to that of α-naphthaleneacetic acid. Immobilization of α-decalylacetic acid is typically different. Bioassays showed α-naphthaleneacetic acid as the sole biologically active component. It is concluded that stereo requirements necessary for biological activity are also required for polar auxin transport. It is further concluded that the observed specificity of the transport system is not related to the formation of immobilization products.