title: Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors.
abstract: Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism.  In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side.  Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip.  Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip.  The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.
authors.affiliation: Department of Botany, Ohio State University, Columbus 43210, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: T J
authors.initials: TJ
authors.lastname: Mulkey
authors.forename: M L
authors.initials: ML
authors.lastname: Evans
mesh_terms: D000490:Allium / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000493:pharmacokinetics; D002132:Calcium Radioisotopes / Q000493:pharmacokinetics; D005449:Fluorenes / Q000494:pharmacology; D006112:Gravitation; D018522:Gravitropism / Q000187:drug effects* / Q000502:physiology; D006540:Herbicides / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018532:Pisum sativum / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D010797:Phthalimides / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D014283:Triiodobenzoic Acids / Q000494:pharmacology; D003313:Zea mays / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D002132:Calcium Radioisotopes; D005449:Fluorenes; D006540:Herbicides; D007210:Indoleacetic Acids; D010797:Phthalimides; D010937:Plant Growth Regulators; D014283:Triiodobenzoic Acids; C005243:morphactins; C002687:alpha-naphthylphthalamic acid; C030737:indoleacetic acid; C052968:2,3,5-triiodobenzoic acid; D002122:Calcium Chloride; D002118:Calcium