Fig. 2

The preparing method of whole section of starchy seed. a, b the small seeds and the pieces of large seeds were glued to resin blocks (a-①, a-②), and the resin blocks and some large seeds (a-③) were clamped in the trimmer (a). c Sample surface was trimmed using a razor blade. d The surface was polished by a glass knife. e For floury seeds, the polished surface of sample was covered with transparent nail polish. f The excess nail polish was removed from sample surface using glass knife after nail polish solidification. g The hook was put near the blade edge before cutting. h, i A semithin section of 2 μm thickness was sectioned with the hook preventing section curling up or down. j The section was transferred to the slide with the hook