Fig. 4.

Structure of pansy seed at three stages of germination. The experiment procedure is described in “Methods” section. Seeds at three different duration of watering are shown as 3D rendering models produced using the program Drishti [36]. a Outlines (top) and cross-sections (bottom) of whole seeds from low-resolution observations. b Whole embryos segmented from high-resolution observations. Lateral streaks on the embryo surface are artifacts due to a technical limitation of the manual segmentation. c Six transverse slices that equally divide an embryo in b from the top to the bottom. Relative positions of the slices are indicated in the dry-seed panel. The perspective is from the right side in b. Scale bars: 300 μm in a, b and 50 μm in c