Signal Transduction in Sinapis alba Root Hairs: Auxins as External Messengers

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dc.contributor.author Tretyn, Andrzej
dc.contributor.author Wagner, Gottfried
dc.contributor.author Felle, Hubert H.
dc.date.accessioned 2017-04-27T09:49:29Z
dc.date.available 2017-04-27T09:49:29Z
dc.date.issued 1991-04-29
dc.identifier.citation Journal of Plant Physiology Vol. 139, 1991, pp. 187-193
dc.identifier.issn 0176-1617
dc.identifier.other DOI: 10.1016/S0176-1617(11)80606-1
dc.identifier.uri http://repozytorium.umk.pl/handle/item/4317
dc.description.abstract In developing root hairs of Sinapis alba the effects of externally applied indole-3-acetic acid (IAA) and other auxins have been investigated with respect to membrane potential, membrane conductance, cytosolic Ca2 + and pH. Following a delay of roughly 30s, 10- 12 to lO- IO M IAA slowly hyperpolarize, 10- 7 M IAA rapidly depolarize the root hairs, while 10- 9 M has hardly an effect. We show that these voltage responses are not the result of a change in membrane conductance or permeability, but are presumably caused by a change in H+ ATPase activity. The other tested auxins and analogues yielded comparable effects, but with much lower effectivity (IAA > 1-NAA > 2,4-D ~ 2-NAA > 2,3-D). Cytosolic Ca2+ and pH were decreased during depolarization by 0.2 and 0.4 units, respectively. No such changes were observed during hyperpolarization or about 1 h after the first encounter of the root hairs with IAA. We propose that IAA is a natural external signal for roots while competing with neighboring organisms for nutrients and salts, and suggest a signal chain with the plasma membrane H+ ATPase as a target protein. The delay in response to IAA, the time dependency, and the extremely low effective IAA concentrations point to the existence of a IAA receptor. Since the IAA-induced shifts in cytosolic pH and Ca2+ occur simultaneously with the depolarization, the question whether these ions are cellular messengers and part of an IAA-triggered signal chain is critically discussed.
dc.description.sponsorship This work was supported by the Deutsche Forschungsgemeinschaft (H.F.) and the Alexander von Humboldt Foundation, Germany (A.T.).
dc.language.iso eng
dc.publisher Gustav Fischer Verlag, Stuttgart
dc.rights Attribution-NonCommercial-NoDerivs 3.0 Poland
dc.rights info:eu-repo/semantics/openAccess
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/pl/
dc.subject Auxin
dc.subject cytosolic Ca2+
dc.subject cytosolic pH
dc.subject membrane potential
dc.subject root hairs
dc.subject signal chain
dc.subject Sinapis alba
dc.title Signal Transduction in Sinapis alba Root Hairs: Auxins as External Messengers
dc.type info:eu-repo/semantics/article

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