Generation of action potential-type changes in response to darkening and illumination as indication of the plasma membrane proton pump status in Marchantia polymorpha

• Published in: Acta physiologiae plantarum 2017-03, Vol.39 (3), p.1-11, Article 82
• Main Authors: Kupisz, Kamila, Dziubińska, Halina, Trębacz, Kazimierz
• Format: Article
• Language: English
• Subjects: Action potential; Adenosine triphosphatase; Agriculture; Bioelectricity; Biomedical and Life Sciences; Darkening; Diuron; Energy balance; H+-transporting ATPase; Illumination; Indication; Life Sciences; Light intensity; Luminous intensity; Membrane potential; Original Article; Photons; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plants (botany); Proton pump inhibitors; Protons; Regulators; Thalli; Thallus
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-017-2378-9

The aim of the present study was to characterise bioelectrical changes in the membrane potential of Marchantia polymorpha gametophyte cells after light/dark transitions and to determine the role of the proton pump and energy status of the M. polymorpha cells in generation of these changes. Darkening caused persistent depolarisation of the resting potential (RP) and generation of short-lasting potential changes that were not uniform among different thalli. In some plants (18%), the changes evoked by darkening were typical action potentials (APs dark ), whereas in 69% of the plants, the changes had a form of action potential-like responses (APs dark -like) consisting of a transient depolarisation followed by a plateau phase, whose magnitude and duration were inconstant. The illumination of the M. polymorpha always evoked action potentials (APs light ) if the thallus was illuminated with light intensity of at least 120 µmol photons m −2  s −1 after 30-min darkening. To analyse the involvement of H + -ATPase in formation of the illumination/darkening-induced electrical responses in M. polymorpha, the proton pump regulators were used. The proton pump inhibitor (20 µM FCCP) significantly diminished the RP and inhibited dark-induced AP dark and/or AP dark -like responses and illumination-induced APs light . After application of DCMU (20 µM), the RP was strongly depolarised and no response to light/dark was observed. Fusicoccin (20 µM), i.e., an activator of the proton pump, strongly hyperpolarised the membrane potential and blocked dark-induced AP dark /AP dark -like responses and illumination-induced APs light .