title: Silicon Promotes Exodermal Casparian Band Formation in Si-Accumulating and Si-Excluding Species by Forming Phenol Complexes.
abstract: We studied the effect of Silicon (Si) on Casparian band (CB) development, chemical composition of the exodermal CB and Si deposition across the root in the Si accumulators rice and maize and the Si non-accumulator onion. Plants were cultivated in nutrient solution with and without Si supply. The CB development was determined in stained root cross-sections. The outer part of the roots containing the exodermis was isolated after enzymatic treatment. The exodermal suberin was transesterified with MeOH/BF3 and the chemical composition was measured using gas chromatography-mass spectroscopy (GC-MS) and flame ionization detector (GC-FID). Laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) was used to determine the Si deposition across root cross sections. Si promoted CB formation in the roots of Si-accumulator and Si non-accumulator species. The exodermal suberin was decreased in rice and maize due to decreased amounts of aromatic suberin fractions. Si did not affect the concentration of lignin and lignin-like polymers in the outer part of rice, maize and onion roots. The highest Si depositions were found in the tissues containing CB. These data along with literature were used to suggest a mechanism how Si promotes the CB development by forming complexes with phenols.
authors.affiliation: Institute of Plant Nutrition, Faculty of Natural Sciences, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
authors.forename: Alexander T
authors.initials: AT
authors.lastname: Fleck
authors.affiliation: Institute of Plant Nutrition, Faculty of Natural Sciences, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Schulze
authors.affiliation: Institute of Plant Nutrition, Faculty of Natural Sciences, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hinrichs
authors.affiliation: Institute of Plant Nutrition, Faculty of Natural Sciences, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Specht
authors.affiliation: Institute of Cellular and Molecular Botany, Department of Ecophysiology, University of Bonn, Kirschallee 1, 53115, Bonn, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Waßmann
authors.affiliation: Institute of Cellular and Molecular Botany, Department of Ecophysiology, University of Bonn, Kirschallee 1, 53115, Bonn, Germany.
authors.forename: Lukas
authors.initials: L
authors.lastname: Schreiber
authors.affiliation: Institute of Plant Nutrition, Faculty of Natural Sciences, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
authors.forename: Manfred K
authors.initials: MK
authors.lastname: Schenk
mesh_terms: D019697:Onions / Q000187:drug effects* / Q000254:growth & development; D012275:Oryza / Q000187:drug effects* / Q000254:growth & development; D010636:Phenols / Q000494:pharmacology*; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development; D012825:Silicon / Q000494:pharmacology*; D003313:Zea mays / Q000187:drug effects* / Q000254:growth & development
chemical_list: D010636:Phenols; D012825:Silicon