title: Differential role of ethylene and hydrogen peroxide in dark-induced stomatal closure.
abstract: Regulation of stomatal aperture is crucial in terrestrial plants for controlling water loss and gaseous exchange with environment. While much is known of signaling for stomatal opening induced by blue light and the role of hormones, little is known about the regulation of stomatal closing in darkness. The present study was aimed to verify their role in stomatal regulation in darkness. Epidermal peelings from the leaves of Commelina benghalensis were incubated in a defined medium in darkness for 1 h followed by a 1 h incubation in different test solutions [H2O2, propyl gallate, ethrel (ethylene), AgNO3, sodium orthovanadate, tetraethyl ammonium chloride, CaCl2, LaCl3, separately and in combination] before stomatal apertures were measured under the microscope. In the dark stomata remained closed under treatments with ethylene and propyl gallate but opened widely in the presence of H2O2 and AgNO3. The opening effect was largely unaffected by supplementing the treatment with Na-vanadate (PM H+ ATPase inhibitor) and tetraethyl ammonium chloride (K(+)-channel inhibitor) except that opening was significantly inhibited by the latter in presence of H2O2. On the other hand, H2O2 could not override the closing effect of ethylene at any concentrations while a marginal opening of stomata was found when Ag NO3 treatment was given together with propyl gallate. CaCl2 treatment opened stomata in the darkness while LaCl3 maintained stomata closed. A combination of LaCl3 and propyl gallate strongly promoted stomatal opening. A probable action of ethylene in closing stomata of Commelina benghalensis in dark has been proposed.
authors: Plant Physiology and Biochemistry Laboratory, Department of Botany, Visva-Bharati University, Santiniketan-731 235, West Bengal, India.
authors: R K
authors: RK
authors: Kar
authors: Department of Botany, Biology-1, Biocentre, Ludwig Maximillians, University of Munich, 82152 Martinsried, Germany.
authors: N
authors: N
authors: Parvin
authors: Centre for Plant Molecular Biology, Eberhard Karls, University of Tuebingen, Auf der Morgenstelle 1, 72076 Tuebingen, Germany.
authors: D
authors: D
authors: Laha
mesh_terms: D002122:Calcium Chloride / Q000494:pharmacology; D034822:Commelina / Q000187:drug effects* / Q000502:physiology; D003623:Dark Adaptation / Q000187:drug effects*; D003624:Darkness; D005030:Ethylenes / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007811:Lanthanum / Q000494:pharmacology; D054046:Plant Stomata / Q000187:drug effects* / Q000502:physiology; D011435:Propyl Gallate / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D012835:Silver Nitrate / Q000494:pharmacology; D019789:Tetraethylammonium / Q000494:pharmacology; D014638:Vanadates / Q000494:pharmacology
chemical_list: D005030:Ethylenes; C028521:lanthanum chloride; D014638:Vanadates; D019789:Tetraethylammonium; D007811:Lanthanum; D011435:Propyl Gallate; C036216:ethylene; D012835:Silver Nitrate; D006861:Hydrogen Peroxide; D002122:Calcium Chloride