title: Enhanced cellulose orientation analysis in complex model plant tissues.
abstract: The orientation distribution of cellulose microfibrils in the plant cell wall is a key parameter for understanding anisotropic plant growth and mechanical behavior. However, precisely visualizing cellulose orientation in the plant cell wall has ever been a challenge due to the small size of the cellulose microfibrils and the complex network of polymers in the plant cell wall. X-ray diffraction is one of the most frequently used methods for analyzing cellulose orientation in single cells and plant tissues, but the interpretation of the diffraction images is complex. Traditionally, circular or square cells and Gaussian orientation of the cellulose microfibrils have been assumed to elucidate cellulose orientation from the diffraction images. However, the complex tissue structures of common model plant systems such as Arabidopsis or aspen (Populus) require a more sophisticated approach. We present an evaluation procedure which takes into account the precise cell geometry and is able to deal with complex microfibril orientation distributions. The evaluation procedure reveals the entire orientation distribution of the cellulose microfibrils, reflecting different orientations within the multi-layered cell wall. By analyzing aspen wood and Arabidopsis stems we demonstrate the versatility of this method and show that simplifying assumptions on geometry and orientation distributions can lead to errors in the calculated microfibril orientation pattern. The simulation routine is intended to be used as a valuable tool for nanostructural analysis of plant cell walls and is freely available from the authors on request.
authors.affiliation: Max-Planck-Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, D-14476 Potsdam, Germany; Swiss Federal Institute of Technology Zurich (ETH Zurich), Institute for Building Materials, Schafmattstrasse 6, CH-8093 Zurich, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Applied Wood Materials, Ueberlandstrasse 129, CH-8600 Dubendorf, Switzerland. Electronic address: markus.rueggeberg@empa.ch.
authors.forename: Markus
authors.initials: M
authors.lastname: Rüggeberg
authors.affiliation: Max-Planck-Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, D-14476 Potsdam, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Saxe
authors.affiliation: Max-Planck-Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, D-14476 Potsdam, Germany.
authors.forename: Till H
authors.initials: TH
authors.lastname: Metzger
authors.affiliation: Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Science SLU, SE-90183 Umea, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Sundberg
authors.affiliation: Max-Planck-Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, D-14476 Potsdam, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Fratzl
authors.affiliation: Max-Planck-Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, D-14476 Potsdam, Germany; Swiss Federal Institute of Technology Zurich (ETH Zurich), Institute for Building Materials, Schafmattstrasse 6, CH-8093 Zurich, Switzerland; Swiss Federal Laboratories for Materials Science and Technology (EMPA), Applied Wood Materials, Ueberlandstrasse 129, CH-8600 Dubendorf, Switzerland.
authors.forename: Ingo
authors.initials: I
authors.lastname: Burgert
mesh_terms: D017360:Arabidopsis / Q000648:ultrastructure*; D002473:Cell Wall; D002482:Cellulose / Q000648:ultrastructure*; D020894:Microfibrils / Q000648:ultrastructure; D018547:Plant Stems / Q000648:ultrastructure; D032107:Populus / Q000648:ultrastructure*; D014934:Wood / Q000648:ultrastructure; D014961:X-Ray Diffraction
chemical_list: D002482:Cellulose
keywords: Arabidopsis; Cellulose microfibril angle; Genetic modification; Plant cell walls; Populus; X-ray diffraction