Spontaneous oscillations of extracellular electrical potentials measured on Lepidium sativum L. roots |
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Authors: | B HECKS Z HEJNOWICZ A SIEVERS |
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Institution: | Botanisches Institut, Universität Bonn, Venusbergweg 22, W-5300 Bonn, Germany |
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Abstract: | Abstract. Electrical potential differences (PDs) were measured continuously at six points in line on the surface of primary roots of cress ( Lepidium sativum L.). The root-to-hypocotyl transition was used as the reference. A gradient of extracellular potentials existed along the root axis. The most negative potentials were observed at the root tip. Whenever the growth rate declined to 0·10 mm h−1 or less, the PDs were nearly constant in space and time. Otherwise, the PDs showed different types of changes with time. Roots with growth rates between 0·65 and 1·10 mm h−1 preferably showed PDs characterized by approximately sinoidal oscillations. Maximal amplitudes appeared in the middle of the elongation zone. Roots which were exposed to a N2-atmosphere exhibited a reversible disappearance of the electrical oscillations and a decrease in the PD-gradient. Similar effects were obtained by the application of the metabolic inhibitor azide (N3−). These results proved that the electrical oscillations are dependent on the aerobic cell metabolism. |
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Keywords: | Lepidium sativum L Brassicaceae cress electrical oscillations (root) extracellular potential (root) growth rate (root) root (growth and electrical oscillations) |
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