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Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle
Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle
Winfried S. Peters
In excised Zea mays L. coleoptiles incubated in aerated media at high fresh weight per volume ratios, indole-3-acetic acid induces transient drops of extracellular pH. Based on the quantitative dependency of the response on the initial auxin concentration we developed a novel auxin bioassay, which allows reliable estimation of IAA concentrations between 10−8.5 and 10−5 M. Using the bioassay and complementary concentration measurements by IAA fluorescence we found the transient IAA-induced pH response paralleled by a decrease of auxin activity and concentration in the medium. This decline is rapid and starts immediately upon auxin addition, and insofar differs from the …