title: Limitation of Cell Elongation in Barley (Hordeum vulgare L.) Leaves Through Mechanical and Tissue-Hydraulic Properties.
abstract: The aim of the present study was to assess the mechanical and hydraulic limitation of growth in leaf epidermal cells of barley (Hordeum vulgare L.) in response to agents which affect cellular water (mercuric chloride, HgCl(2)) and potassium (cesium chloride, CsCl; tetraethylammonium, TEA) transport, pump activity of plasma membrane H(+)-ATPase and wall acidification (fusicoccin, FC). Cell turgor (P) was measured with the cell pressure probe, and cell osmotic pressure (π) was analyzed through picoliter osmometry of single-cell extracts. A wall extensibility coefficient (M) and tissue hydraulic conductance coefficient (L) were derived using the Lockhart equation. There was a significant positive linear relationship between relative elemental growth rate and P, which fit all treatments, with an overall apparent yield threshold of 0.368 MPa. Differences in growth between treatments could be explained through differences in P. A comparison of L and M showed that growth in all except the FC treatment was co-limited through hydraulic and mechanical properties, though to various extents. This was accompanied by significant (0.17-0.24 MPa) differences in water potential (ΔΨ) between xylem and epidermal cells in the leaf elongation zone. In contrast, FC-treated leaves showed ΔΨ close to zero and a 10-fold increase in L.
authors.affiliation: Department of Biology, Faculty of Nature and Life Sciences, University Ziane Achour, Djelfa, Algeria.
authors.forename: Mostefa
authors.initials: M
authors.lastname: Touati
authors.affiliation: University College Dublin, School of Biology and Environmental Science, Science Centre West, Belfield, Dublin 4, Ireland Present address: Department of Viticulture and Enology, University of California, Davis, CA 95616-5270, USA.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Knipfer
authors.affiliation: University College Dublin, School of Biology and Environmental Science, Science Centre West, Belfield, Dublin 4, Ireland Present address: Research, Chemical Works of Gedeon Richter Plc., H-1103 Budapest, Gyömrői út 19-21, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Visnovitz
authors.affiliation: Laboratoire d'Eco-Physiologie Végétale, Département des Sciences Naturelles, Ecole Normale Supérieure de Kouba, 16050, Alger, Algeria.
authors.forename: Abdelkrim
authors.initials: A
authors.lastname: Kameli
authors.affiliation: University College Dublin, School of Biology and Environmental Science, Science Centre West, Belfield, Dublin 4, Ireland Wieland02fricke@yahoo.co.uk.
authors.forename: Wieland
authors.initials: W
authors.lastname: Fricke
mesh_terms: D000465:Algorithms; D001692:Biological Transport / Q000187:drug effects; D001696:Biomechanical Phenomena / Q000187:drug effects / Q000502:physiology; D049108:Cell Enlargement; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D002586:Cesium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D006027:Glycosides / Q000494:pharmacology; D001467:Hordeum / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008627:Mercuric Chloride / Q000494:pharmacology; D008954:Models, Biological; D009997:Osmotic Pressure / Q000187:drug effects; D019441:Plant Epidermis / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D018526:Plant Transpiration / Q000187:drug effects / Q000502:physiology; D006180:Proton-Translocating ATPases / Q000378:metabolism; D019789:Tetraethylammonium / Q000494:pharmacology; D014867:Water / Q000378:metabolism*
chemical_list: D002712:Chlorides; D006027:Glycosides; D014867:Water; D002586:Cesium; C007808:fusicoccin; D008627:Mercuric Chloride; D019789:Tetraethylammonium; D006180:Proton-Translocating ATPases; C028019:cesium chloride
keywords: Barley (Hordeum vulgare L.); Fusicoccin; Hydraulic conductivity; Leaf cell elongation; Lockhart equation; Turgor