Characterizing Cellulose Crystallographic Texture in Plant Cell Walls Using Grazing Incidence X-ray Scattering*

Cellulose, the most abundant biopolymer on earth, is a versatile material with tuneable properties. It exists as semi - crystalline microfibrils in plant cell walls. This crystalline structure is important for plant growth and determines properties of cellulosic materials. However, several aspects of this crystalline structure remain elusive - one of them being orientation of cellulose crystallites. We studied the structure of cellulose in plant primary cell walls through grazing incidence wide angle X-ray scattering (GIWAXS). GIWAXS of cell wall reveal strong texturing of cellulose. The degree of texturing is determined through pole figures constructed from combination of GIWAXS and XRD rocking scans. We find that cellulose texturing depends on developmental age of tissue. GIWAXS of cell wall mutants reveals interactions between wall polysaccharides. We find that cellulose texture is disrupted in pectin and cellulose mutants but not in xyloglucan mutants. These findings provide insights on cellulose crystalline structure which can help design cellulose-like materials and efficient biomass conversion process.