Roles of Cellulose and Xyloglucan in Determining the Mechanical Properties of Primary Plant Cell Walls1
AUTOR(ES)
Whitney, Sarah E.C.
FONTE
American Society of Plant Physiologists
RESUMO
The primary cell walls of growing and fleshy plant tissue mostly share a common set of molecular components, cellulose, xyloglucan (XyG), and pectin, that are required for both inherent strength and the ability to respond to cell expansion during growth. To probe molecular mechanisms underlying material properties, cell walls and analog composites from Acetobacter xylinus have been measured under small deformation and uniaxial extension conditions as a function of molecular composition. Small deformation oscillatory rheology shows a common frequency response for homogenized native cell walls, their sequential extraction residues, and bacterial cellulose alone. This behavior is characteristic of structuring via entanglement of cellulosic rods and is more important than cross-linking with XyG in determining shear moduli. Compared with cellulose alone, composites with XyG have lower stiffness and greater extensibility in uniaxial tension, despite being highly cross-linked at the molecular level. It is proposed that this is due to domains of cross-linked cellulose behaving as mechanical elements, whereas cellulose alone behaves as a mat of individual fibrils. The implication from this work is that XyG/cellulose networks provide a balance of extensibility and strength required by primary cell walls, which is not achievable with cellulose alone.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=59429Documentos Relacionados
- The Structure of Plant Cell Walls: V. On the Binding of Xyloglucan to Cellulose Fibers 1
- The Galactose Residues of Xyloglucan Are Essential to Maintain Mechanical Strength of the Primary Cell Walls in Arabidopsis during Growth1
- Studies of Streptococcal Cell Walls VII. Carbohydrate Composition of Group B Cell Walls1
- Borate-Rhamnogalacturonan II Bonding Reinforced by Ca2+ Retains Pectic Polysaccharides in Higher-Plant Cell Walls1
- Paper Chromatographic System for the Identification of Glycerol in Bacterial Cell Walls1