Modes of failure of rose prickles submitted to mechanical tests.
Figures are generally photos, graphs and static images that would be represented in traditional pdf publications.
Pictures, schematic drawings with typical crack location indicated by a red line and typical force-displacement-diagrams are shown. The initial displacements with almost zero force in the force-displacement diagrams represent the first testing phase when the Kevlar loop gets straightened before the force is exerted on the prickle. a) failure within the prickle (picture Rosa arvensis), b) failure just above the cork layer (picture R. arvensis), c) failure just beneath the cork layer (picture R arvensis) and d) failure within the cortical parenchyma of the stem (picture Rosa arvensis ‘Splendens‘ type II).