(729d) Grazing Incidence X-Ray Scattering Reveals Texturing in Plant Cell Walls

Plant cell wall is a complex heterogeneous mixture of several biopolymers including cellulose, hemicellulose and pectin. Its major component cellulose is an important biopolymer for renewable energy, paper, textile and construction materials. Within the cell walls, cellulose exists as microfibrils forming a crystalline structure that plays an important role in the biological processes of plant growth, conversion of cellulosic biomass into biofuels and also in understanding the physical properties of cellulose derivatives. However, many aspects of crystalline cellulose, like the orientation of the crystals within the fibrils, are still not well understood. We studied the structure of cellulose in primary cell walls of plants through grazing incidence X-ray scattering. It is a morphological characterization tool that can probe the sample surface as well as beneath it. The grazing incidence geometry yields high signal-to-noise ratio and causes lesser radiation damage, making it ideal for plant cell wall samples that are fragile and weakly scattering. We found that the technique could decouple scattering from cellulose and wax crystals. X-ray scattering of different chemical treatments of the cell wall revealed strong texturing of cellulose. The degree of preferred orientation of the crystals was determined through the construction of pole figures. It was found that the texturing depends on the developmental age of the tissue and also on its source.