The Regulation of Anion Loading to the Maize Root Xylem

Simple item page
dc.contributor.authorGilliham, M.
dc.contributor.authorTester, M.
dc.date.issued2005
dc.description.abstractThe regulation of anion loading to the shoot in maize (Zea mays) was investigated via an electrophysiological characterization of ion conductances in protoplasts isolated from the root stele. Two distinct anion conductances were identified. In protoplasts from well-watered plants, Z. mays xylem-parenchyma quickly-activating anion conductance (Zm-X-QUAC) was the most prevalent conductance and is likely to load the majority of NOâ â » and Clâ » ions to the xylem in nonstressed conditions. Z. mays xylem-parenchyma inwardly-rectifying anion conductance was found at a lower frequency in protoplasts from well-watered plants than Zm-X-QUAC, was much smaller in magnitude in all observed conditions, and is unlikely to be such a major pathway for anion loading into the xylem. Activity of Z. mays xylem-parenchyma inwardly-rectifying anion conductance increased following a water stress prior to protoplast isolation, but the activity of the putative major anion-loading pathway, Zm-X-QUAC, decreased. Addition of abscisic acid (ABA) to protoplasts from well-watered plants also inhibited Zm-X-QUAC activity within minutes, as did a high free Ca²⠺ concentration in the pipette. ABA was also seen to activate a Ca²⠺-permeable conductance (Z. mays xylem-parenchyma hyperpolarization activated cation conductance) in protoplasts from well-watered plants. It is postulated that the inhibition of anion loading into the xylem (an important response to a water stress) due to down-regulation of Zm-X-QUAC activity is mediated by an ABA-mediated rise in free cytosolic Ca²⠺.
dc.identifier.citationPlant Physiology, 2005; 137(3):819-828
dc.identifier.doi10.1104/pp.104.054056
dc.identifier.issn0032-0889
dc.identifier.issn1532-2548
dc.identifier.orcidGilliham, M. [0000-0003-0666-3078]
dc.identifier.urihttp://hdl.handle.net/2440/34561
dc.language.isoen
dc.publisherAmer Soc Plant Physiologists
dc.rights© 2005 American Society of Plant Biologists
dc.source.urihttp://www.plantphysiol.org/cgi/content/full/137/3/819
dc.subjectProtoplasts
dc.subjectZea mays
dc.subjectPlant Roots
dc.subjectChlorides
dc.subjectAnions
dc.subjectIodides
dc.subjectNitrates
dc.subjectSulfates
dc.subjectCalcium
dc.subjectWater
dc.subjectMalates
dc.subjectCitric Acid
dc.subjectAbscisic Acid
dc.subjectElectrophysiology
dc.subjectBiological Transport, Active
dc.titleThe Regulation of Anion Loading to the Maize Root Xylem
dc.typeJournal article
pubs.publication-statusPublished

Files

Collections

Agriculture, Food and Wine publications