title: Mechanical properties of primary plant cell wall analogues.
abstract: Mechanical effects of turgor pressure on cell walls were simulated by deforming cell wall analogues based on Acetobacter xylinus cellulose under equi-biaxial tension. This experimental set-up, with associated modelling, allowed quantitative information to be obtained on cellulose alone and in composites with pectin and/or xyloglucan. Cellulose was the main load-bearing component, pectin and xyloglucan leading to a decrease in modulus when incorporated. The cellulose-only system could be regarded as an essentially linear elastic material with a modulus ranging from 200 to 500 MPa. Pectin incorporation modified extensibility properties of the system by topology/architecture changes of cellulose fibril assemblies, but the cellulose/pectin composites could still be described as a linear elastic material with a modulus ranging from 120 to 250 MPa. The xyloglucan/cellulose composite could not be modelled as a linear elastic material. Introducing xyloglucan into a cellulose network or a cellulose/pectin composite led to very compliant materials characterised by time-dependent creep behaviour. Modulus values obtained for the composite materials were compared with mechanical data found for plant-derived systems. After comparing bi-axial and uni-axial behaviour of the different composites, structural models were proposed to explain the role of each polysaccharide in determining the mechanical properties of these plant primary cell wall analogues.
mesh_terms: D000091:Acetobacter / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D001696:Biomechanical Phenomena; D002473:Cell Wall / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure; D002482:Cellulose / Q000378:metabolism* / Q000648:ultrastructure; D004548:Elasticity; D005936:Glucans; D020894:Microfibrils / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008954:Models, Biological; D009997:Osmotic Pressure; D010368:Pectins / Q000378:metabolism; D010944:Plants / Q000737:chemistry* / Q000648:ultrastructure; D011134:Polysaccharides / Q000378:metabolism; D013314:Stress, Mechanical; D014990:Xylans
chemical_list: D005936:Glucans; D011134:Polysaccharides; D014990:Xylans; C029353:xyloglucan; D010368:Pectins; D002482:Cellulose