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The Correlation Of Profiles Of Surface Ph And Elongation Growth In Maize Roots, Winfried Peters, Hubert Felle
The Correlation Of Profiles Of Surface Ph And Elongation Growth In Maize Roots, Winfried Peters, Hubert Felle
Winfried S. Peters
High-resolution profiles of surface pH and growth along vertically growing maize (Zea mays) primary root tips were determined simultaneously by pH-sensitive microelectrodes and marking experiments. Methodological tests were carried out that proved the reliability of our kinematic growth analysis, while questioning the validity of an alternative technique employed previously. A distal acidic zone around the meristematic region and a proximal one around the elongation zone proper were detected. This pattern as such persisted irrespective of the bulk pH value. The proximal acidic region coincided with maximum relative elemental growth rates (REGR), and both characters reacted in a correlated …
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 …
The Electrical Response Of Maize To Auxin, Hubert Felle, Winfried Peters, Klaus Palme
The Electrical Response Of Maize To Auxin, Hubert Felle, Winfried Peters, Klaus Palme
Winfried S. Peters
The electrical response of Zea mays coleoptiles and suspension cultured cells to several growth-promoting auxins (IAA, IBA, 2,4-D, 2,4,5-T, 1-NAA) and some of their structural analogues (2,3-D, 2-NAA) has been tested. In coleoptiles two typical electrical responses to IAA are observed: an immediate rapid depolarization, and a hyperpolarization following 7–10 minutes after the first external addition of IAA. Of the other tested compounds only 1-NAA significantly depolarized the cells, whereas all auxins as well as the analogues evoked delayed hyperpolarizations. In contrast, the suspension cells were not hyperpolarized by any of the tested compounds, but were strongly depolarized by IAA, …