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Full-Text Articles in Botany
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, …
Control Of Apoplast Ph In Corn Coleoptile Segments. I: The Endogenous Regulation Of Cell Wall Ph, Winfried Peters, Hubert Felle
Control Of Apoplast Ph In Corn Coleoptile Segments. I: The Endogenous Regulation Of Cell Wall Ph, Winfried Peters, Hubert Felle
Winfried S. Peters
The endogenous control of cell wall pH of Zea mays L. coleoptiles has been investigated using abraded as well as non-abraded segments. Regardless of the initial medium pH, coleoptile segments characteristically change the external pH: after about 2 h a pH maximum (neutral peak; NP) around 6 is reached, followed by a slow pH decrease that levels off in a steady state at 4.8 after 7 h (acid equilibrium; AE). This basic behavior is independent of medium composition, but critically requires O2; it is not altered when the number of coleoptiles per volume is increased to over 10 col./mL. Thus, …
Control Of Apoplast Ph In Corn Coleoptile Segments. Ii: The Effects Of Various Auxins And Auxin Analogues, Winfried Peters, Hubert Felle
Control Of Apoplast Ph In Corn Coleoptile Segments. Ii: The Effects Of Various Auxins And Auxin Analogues, Winfried Peters, Hubert Felle
Winfried S. Peters
Using abraded Zea mays L. coleoptile segments, proton extrusion has been measured in the presence of growth promoting auxins and their inactive structural analogues. Prior to application, the segments spontaneously acidified the external medium to pH 4.8 within 7 h. Indole-3-acetic acid (IAA) concentration dependently decreases external pH to 4.2, fusicoccin (FC) to below 3.5. Whereas the IAA-effect spontaneously recovers and can be repeated, the FC-effect is final and irreversible. The growth promoting auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), indole-3-butyric acid (IBA) and 1-naphthylacetic acid (1-NAA) all stimulate proton extrusion similar to IAA. The growth inactive structural analogues 2,3-dichlorophenoxyacetic …