Photoregulation of Proton Extrusion by Cucumber Hypocotyls and the Role of ATPase Activity

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5 Scopus citations


The photoregulation of H+ extrusion by hypocotyl segments of Cucumis sativus L. was studied. Irradiation with red light (to give Pfr) enhanced H+ efflux in the presence of Mg2+ and K+. This effect of red light was decreased by far red irradiation (to give Pr). The acidification was inhibited by sodium orthovanadate. These results imply that H+ extrusion is coupled to plasma membrane ATPase activity. In vivo pretreatment with filipin, which interferes with phytochrome association with membranes, reduced both photoregulation of ATPase activity and H+ extrusion. A similar effect was found after preirradiation with red light before a prolonged dark period at 4 °C, a treatment which is assumed to lower phytochrome levels.

Original languageEnglish
Pages (from-to)329-336
Number of pages8
JournalJournal of Plant Physiology
Issue number4
StatePublished - 1 Jan 1986
Externally publishedYes


  • ATP-ase
  • Acidification
  • Cucumis sativus
  • phytochrome
  • vanadate

ASJC Scopus subject areas

  • Physiology
  • Agronomy and Crop Science
  • Plant Science


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