Microscopic and NMR analysis of the external coat from seeds of Magonia pubescens.

•  The chemical composition and structure of the layers of the external coat and the three-dimensional organization of the gel during the swelling process are reported here for seeds of Magonia pubescens. •  Histochemical-light and scanning electron microscopy (SEM) were used in conjunction with CP-MAS (cross polarization - magic angle spinning: solid state) C NMR spectroscopy to analyse the seed coat layers. •  M.