Abstract text: Hemicelluloses are chemically diverse polysaccharide components of plant cell walls, where they form a composite structure with cellulose. Although their chemical structure is suggested to influence cell wall structure formation, their role in controlling the nanostructure of newly synthesized cellulose microfibrils, links to cell wall properties and moisture interactions are poorly understood. Our newly initiated research project aims to address these questions through a combination of experimental and modelling methodologies, using both bottom-up and top-down approaches. In the bottom-up approach, we utilize biomimetic systems to simulate plant cell wall-like cellulose-hemicellulose composites and use electron microscopy, X-ray scattering methods and molecular dynamics simulations, to decipher the role of chemical moieties of hemicelluloses on cellulose fibrillar and crystalline structures. As a top-down approach, we plan to study samples from genetically modified plants deficient in specific hemicelluloses, by spatially resolved scattering and spectroscopy techniques to obtain local information on their nanostructure. We will systematically study the correlations and dependencies between nanostructural features and chemical structure of the cell wall components, aiming to understand the linkage between properties of the plant cell wall and their chemical composition. Through this poster, we will present the overall project strategy and initial results from the bottom-up approach.