Comparison of movement and metabolism of indole‐3‐acetic acid and indole‐3‐butyric acid in mung bean cuttings

Zeev Wiesman, Joseph Riov, Ephraim Epstein

Research output: Contribution to journalArticlepeer-review

89 Scopus citations

Abstract

Indole‐3‐butyric acid (IBA) was much more effective than indole‐3‐acetic acid (IAA) in inducing adventitious root formation in mung bean (Vigna radiata L.) cuttings. Prolonging the duration of treatment with both auxins from 24 to 96 h significantly increased the number of roots formed. Labelled IAA and IBA applied to the basal cut surface of the cuttings were transported acropetally. With both auxins, most radioactivity was detected in the hypocotyl, where roots were formed, but relatively more IBA was found in the upper sections of the cuttings. The rate of metabolism of IAA and IBA in these cuttings was similar. Both auxins were metabolized very rapidly and 24 h after application only a small fraction of the radioactivity corresponded to the free auxins. Hydrolysis with 7 M NaOH indicates that conjugation is the major pathway of IAA and IBA metabolism in mung bean tissues. The major conjugate of IAA was identified tentatively as indole‐3‐acetylaspartic acid, whereas IBA formed at least two major conjugates. The data indicate that the higher root‐promoting activity of IBA was not due to a different transport pattern and/or a different rate of conjugation. It is suggested that the IBA conjugates may be a better source of free auxin than those of IAA and this may explain the higher activity of IBA.

Original languageEnglish
Pages (from-to)556-560
Number of pages5
JournalPhysiologia Plantarum
Volume74
Issue number3
DOIs
StatePublished - 1 Jan 1988
Externally publishedYes

Keywords

  • Auxin conjugates
  • Vigna radiata
  • indole‐3‐acetic acid
  • indole‐3‐butyric acid
  • mung bean
  • rooting

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science
  • Cell Biology

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