Auxin transport and conjugation in cotton explants.

Indoleacetic acid (IAA), a naturally-occurring auxin, prevents or retards abscission of plant parts under many conditions (1). When applied to the cotyledonary petiole stumps of explants of cotton (Gossypium. hirsutum L.) in a commonly used abscission test IAA in moderate physiological coIncentrations retards abscission markedly (2, 6). The disposition within the explant of the auxin applied under these conditions has now been investigated both quantitatively and qualitatively with the use of 14C-labeled IAA. A variety of related investigations have been reported (see 7, 8, 11, 12), but in this brief paper we will comment only on those of immediate relevance to our results. "kJIn 2 replicate experiments with IAA-1-4C and