Indoleacetic acid bioassay

The most promising leads have come from studying the hormonal requirements of the system. By themselves, we can find no indication whatsoever of any growth promotion by any of the alkyl lipides. When gibberellic acid is also applied, response remains small. If indoleacetic acid, or another auxin, is added, the sections show the classic bioassay response—and this is further stimulated by the active lipides. In the presence of both auxin and gibberellic acid, however, the sections show their greatest capacity to elongate still further in the presence of the alkyl lipides (I). Remarkably, the lipides are most effective at concentrations corn-... 

An in vitro bioassay was then performed to measure the auxin-like properties of these compounds, based on a procedure from Cleon Ross(14)(Fig. I). This assay is based in principle on the growth response to auxins of stem segments of Pisum sativum. Measurement of segment weight and transectional area was compared to the untreated control.In this manner, a response curve was obtained for each compound. Indoleacetic acid (IAA) gave a typical response curve, as shown AC 78,299 gave an auxin-like response while AC 78,167 was inactive(Fig. 2). 

Jacobs WP (1976) Apolar movement of zeatin through Coleus petioles and Pisum roots as estimated by bioassay and radioactive labelling. Am J Bot 63 571-577 Jacobs WP (1977) Polarity of indoleacetic acid in young Coleus stems. Plant Physiol 60 95-97... 

Letham DS (1967) Regulators of cell division in plant tissues. V. A comparison of the activities of zeatin and other cytokinins in five bioassays. Planta 74 228-242 Little CHA, Heald JK, Browning G (1978) Identification and measurement of indoleacetic and abscisic acids in the cambial region by combined gas chromatography-mass spectrometry. Planta 139 133-138... 

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