Updated project metadata. In Brassicaceae and other species, the developing embryo develops in a spatially constrained environment, modulating embryo´s shape and size. It is unknown how embryonic cells adapt their growth and metabolism to the apparent mechanical cues, and in particular if embryo maturation is affected by physical constraints. To address this question, we performed topographical analysis (magnetic resonance imaging, infrared microspectroscopy, immunolabelling), metabolite, transcript and proteome profiling in developing seeds of Brassica napus. Here we describe how the imposition of mechanical stress during development causes a stimulation of oil and protein storage activity, characteristic of embryo maturation.