title: Age Effects on Hypocotyl Mechanics.
abstract: Numerous studies deal with composition and molecular processes involved in primary cell wall formation and alteration in Arabidopsis. However, it still remains difficult to assess the relation between physiological properties and mechanical function at the cell wall level. The thin and fragile structure of primary cell walls and their large biological variability, partly related to structural changes during growth, make mechanical experiments challenging. Since, to the best of our knowledge, there is no reliable data in the literature about how the properties of the fully elongated zone of hypocotyls change with age. We studied in a series of experiments on two different seed batches the tensile properties the region below the growth zone of 4 to 7 day old etiolated Arabidopsis hypocotyls. Additionally, we analysed geometrical parameters, hypocotyl density and cellulose content as individual traits and their relation to tissue mechanics. No significant differences of the mechanical parameters of the non-growing region between 5-7 day old plants could be found whereas in 4 day old plants both tensile stiffness and ultimate tensile stress were significantly lower than in the older plants. Furthermore hypocotyl diameters and densities remain almost the same for 5, 6 and 7 day old seedlings. Naturally, hypocotyl lengths increase with age. The evaluation whether the choice-age or length-influences the mechanical properties showed that both are equally applicable sampling parameters. Additionally, our detailed study allows for the estimation of biological variability, connections between mechanics and hypocotyl age could be established and complement the knowledge on biochemistry and genetics affecting primary plant cell wall growth. The application of two different micromechanical devices for testing living Arabidopsis hypocotyls allows for emphasizing and discussing experimental limitations and for presenting a wide range of possibilities to address current and future questions related to plant cell wall mechanics, synthesis and growth in combination with molecular biology methodologies.
authors.affiliation: Department of Biomaterials, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.|Cluster of Excellence »Image Knowledge Gestaltung«, Humboldt University, Berlin, Germany.
authors.forename: Friederike
authors.identifier: http://orcid.org/0000-0002-2569-1173
authors.initials: F
authors.lastname: Saxe
authors.affiliation: Department of Biomaterials, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.
authors.forename: Susann
authors.initials: S
authors.lastname: Weichold
authors.affiliation: Department of Biomaterials, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Reinecke
authors.affiliation: Plant Cell Wall Group, Max-Planck-Institute of Molecular Plant Physiology, Potsdam, Germany.|Charite´-Universitätsmedizin Berlin, Molekulares Krebsforschungszentrum (MKFZ), Berlin, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Lisec
authors.affiliation: Plant Cell Wall Group, Max-Planck-Institute of Molecular Plant Physiology, Potsdam, Germany.|targenomix GmbH, Potsdam, Germany.
authors.forename: Anett
authors.initials: A
authors.lastname: Döring
authors.affiliation: Plant Cell Wall Group, Max-Planck-Institute of Molecular Plant Physiology, Potsdam, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Neumetzler
authors.affiliation: Department of Biomaterials, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.|Institute for Building Materials, Federal Institute of Technology, Zurich, Switzerland.|Applied Wood Materials Laboratory, Swiss Federal Laboratories for Materials Science and Technology, Duebendorf, Switzerland.
authors.forename: Ingo
authors.initials: I
authors.lastname: Burgert
authors.affiliation: Department of Biomaterials, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Eder
mesh_terms: D000375:Aging / Q000502:physiology; D017360:Arabidopsis / Q000378:metabolism / Q000502:physiology; D029681:Arabidopsis Proteins / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism / Q000502:physiology; D002482:Cellulose / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D018546:Hypocotyl / Q000378:metabolism / Q000502:physiology*; D013718:Tensile Strength / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D002482:Cellulose