title: Mechanical properties of plant cell walls probed by relaxation spectra.
abstract: Transformants and mutants with altered cell wall composition are expected to display a biomechanical phenotype due to the structural role of the cell wall. It is often quite difficult, however, to distinguish the mechanical behavior of a mutant's or transformant's cell walls from that of the wild type. This may be due to the plant's ability to compensate for the wall modification or because the biophysical method that is often employed, determination of simple elastic modulus and breakstrength, lacks the resolving power necessary for detecting subtle mechanical phenotypes. Here, we apply a method, determination of relaxation spectra, which probes, and can separate, the viscoelastic properties of different cell wall components (i.e. those properties that depend on the elastic behavior of load-bearing wall polymers combined with viscous interactions between them). A computer program, BayesRelax, that deduces relaxation spectra from appropriate rheological measurements is presented and made accessible through a Web interface. BayesRelax models the cell wall as a continuum of relaxing elements, and the ability of the method to resolve small differences in cell wall mechanical properties is demonstrated using tuber tissue from wild-type and transgenic potatoes (Solanum tuberosum) that differ in rhamnogalacturonan I side chain structure.
authors.affiliation: Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark.
authors.forename: Steen Laugesen
authors.initials: SL
authors.lastname: Hansen
authors.forename: Peter Martin
authors.initials: PM
authors.lastname: Ray
authors.forename: Anders Ola
authors.initials: AO
authors.lastname: Karlsson
authors.forename: Bodil
authors.initials: B
authors.lastname: Jørgensen
authors.forename: Bernhard
authors.initials: B
authors.lastname: Borkhardt
authors.forename: Bent Larsen
authors.initials: BL
authors.lastname: Petersen
authors.forename: Peter
authors.initials: P
authors.lastname: Ulvskov
mesh_terms: D001499:Bayes Theorem; D001696:Biomechanical Phenomena / Q000502:physiology; D002473:Cell Wall / Q000502:physiology*; D004548:Elasticity; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D035281:Plant Tubers / Q000502:physiology; D012212:Rheology; D011198:Solanum tuberosum / Q000166:cytology* / Q000502:physiology; D013314:Stress, Mechanical