Experimental setup for small angle X-ray scattering. a) Setup at the μ-spot beamline (BESSY II). Beam size is adjusted by the pinhole before it hits the sample. The scattered signal is collected on a 2D-detector while the primary beam is kept back by a beam-stop. b) Sample preparation: 6d old, dark grown Arabidopsis thaliana hypocotyls are mounted onto a metal grid in their hydrated state. c) Chara corallina cell is cut open and a single cell wall is placed in the beam. White spots at the lower right of the sample are calciumcarbonate depositions (not relevant for the microfibril measurement). Scalebars: 2 mm.