title: Suberin structure in potato periderm: glycerol, long-chain monomers, and glyceryl and feruloyl dimers.
abstract: Suberin in extractive-free potato periderm amounts to approximately 25% determined by NaOCH(3) methanolysis. Monomeric composition is characterized by glycerol (20% of monomers), long-chain alpha, omega-diacids, omega-hydroxyacids, alkanoic acids, and alkan-1-ols, with predominance of octadec-9-enodioic acid and 18-hydroxyoctadec-9-enoic acid (39 and 15% of long-chain monomers, respectively). Aromatic hydroxycinnamyl monomers were also present (<1%). Partial depolymerization of potato periderm suberin using a Ca(OH)(2)-catalyzed methanolysis solubilized approximately 10% of suberin aliphatics. GC-MS analysis showed the presence of monomers, dimers, and trimers (87, 12, and 1% of identified compounds, respectively). A total of 26 dimers were identified by EIMS: monoacylglyceryl esters of alpha,omega-diacids, omega-hydroxyacids, and alkanoic acids (with predominance of the 1- and 2-isomers of the monoacylglyceryl ester of the octadec-9-enodioic acid), as well as feruloyl esters of omega-hydroxyacids and alkan-1-ols and a small quantity of a monoferuloylglycerol. Following a discussion of suberin macromolecular structure, it is proposed that in suberized cell walls, the polyaliphatic polymers have a three-dimensional development ensured by glycerol and exist independently from the associated polyaromatics.
authors.affiliation: Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade Técnica Lisboa, 1349-017 Lisboa, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Graça
authors.forename: H
authors.initials: H
authors.lastname: Pereira
mesh_terms: D002264:Carboxylic Acids / Q000032:analysis*; D003373:Coumaric Acids / Q000032:analysis; D019281:Dimerization; D008401:Gas Chromatography-Mass Spectrometry; D005990:Glycerol / Q000032:analysis; D006880:Hydroxy Acids / Q000032:analysis; D008055:Lipids; D008563:Membrane Lipids / Q000737:chemistry* / Q000302:isolation & purification; D011198:Solanum tuberosum / Q000737:chemistry*; D018629:Spectrometry, Mass, Secondary Ion
chemical_list: D002264:Carboxylic Acids; D003373:Coumaric Acids; D006880:Hydroxy Acids; D008055:Lipids; D008563:Membrane Lipids; C065875:suberin; C004999:ferulic acid; D005990:Glycerol