ISHS Acta Horticulturae 329: VII International Symposium on Plant Growth Regulators in Fruit Production
ENDOGENOUS AND EXOGENOUS AUXIN CONJUGATES IN ROOTING OF CUTTINGS |
| Author: | J. Riov |
| Keywords: | IAA, IBA, conjugate oxidation |
| Abstract:
Indole-3-butyric acid (IBA) is the most widely used auxin for rooting of cuttings. It was believed that the high rooting ability of IBA results from its high stability within the plant tissues. Labelled IBA and indole-3-acetic acid (IAA) applied to mung bean (Vigna radiata L.) cuttings were metabolized at a similar rate. Both auxins were metabolized very rapidly and 24 hours after application only a small fraction of the radioactivity corresponded to the free auxins. These data suggest that conjugates formed endogenously following auxin application may serve as the source of auxin during most of the rooting process. Endogenously formed conjugates of IBA in mung bean cuttings were characterized and proved to possess high rooting ability. Recent evidence from different laboratories indicate that indole-3-acetylaspartic acid, the major IAA metabolite in many plant species, is subjected to direct oxidation, yielding various biologically inactive oxindole derivatives. Thus, the efficiency of various auxins to induce adventitious root formation seems to depend on the stability of their conjugates. Exogenous auxin conjugates had a higher rooting activity than the corresponding free auxins when applied to cuttings of various species. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
