caa a22 4500 477100236 CHVBK 20180405111539.0 cr unu---uuuuu 170330e19961201xx s 000 0 eng 10.1007/BF00231397 doi (NATIONALLICENCE)springer-10.1007/BF00231397 Induction and ionic basis of slow wave potentials in seedlings of Pisum sativum L [Elektronische Daten] [Rainer Stahlberg, Daniel Cosgrove] Slow wave potentials (SWPs) are transient depolarizations which propagate substantial distances from their point of origin. They were induced in the epidermal cells of pea epicotyls by injurious methods such as root excision and heat treatment, as well as by externally applied, defined steps in xylem pressure (Px)at in the absence of wounding. The common principle of induction was a rapid increase in Px. Such a stimulus appeared under natural conditions after (i) bending of the epicotyl, (ii) wounding of the epidermis, (iii) rewatering of dehydrated roots, and (iv) embolism. The induced depolarization was not associated with a change in cell input resistance. This result and the ineffectiveness of ion channel blockers point to H+-pumps rather than ion channels as the ionic basis of the SWP. Stimuli such as excision, heat treatment and pressure steps, which generate SWPs, caused a transient increase in the fluorescence intensity of epicotyls loaded with the pH-indicator DM-NERF, a 2′, 7′-dimethyl derivative of rhodol, but not of those loaded with the pH indicator 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). Matching kinetics of depolarization and pH response identify a transient inactivation of proton pumps in the plasma membrane as the causal mechanism of the SWP. Feeding pump inhibitors to the cut surface of excised epicotyls failed to chemically simulate a SWP; cyanide, azide and 2,4-dinitrophenol caused sustained, local depolarizations which did not propagate. Of all tested substances, only sodium cholate caused a transient and propagating depolarization whose arrival in the growing region of the epicotyl coincided with a transient growth rate reduction. Springer-Verlag, 1996 Apoplastic pH nationallicence Cell input resistance nationallicence Membrane potential nationallicence pH indicator (DM-NERF) nationallicence Pisum sativum nationallicence Slow wave potential nationallicence Surface potential nationallicence AP : action potential nationallicence BCECF : 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein nationallicence DM-NERF 2′,7′ : dimethyl derivative of rhodol nationallicence GR : growth rate nationallicence Px : xylem pressure nationallicence Rin : cell input resistance nationallicence SWP : slow wave potential nationallicence Vm : membrane potential nationallicence Vs : surface potential nationallicence Stahlberg Rainer Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, 16802, University Park, PA, USA aut Cosgrove Daniel Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, 16802, University Park, PA, USA aut Planta Springer-Verlag 200/4(1996-12-01), 416-425 0032-0935 200:4<416 1996 200 425 https://doi.org/10.1007/BF00231397 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00231397 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Stahlberg Rainer Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, 16802, University Park, PA, USA aut NATIONALLICENCE 700 1- Cosgrove Daniel Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, 16802, University Park, PA, USA aut NATIONALLICENCE 773 0- Planta Springer-Verlag 200/4(1996-12-01), 416-425 0032-0935 200:4<416 1996 200 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer