Fig. 5.

a–k Behaviors of rape pollen during fermentation by S. cerevisiae as observed via SEM. a, b A pollen grain without additional processing. a The parallel view and b is the vertical view of the rape pollen. c Vacuum-freeze dried pollen without fermentation. d–k Behaviors of rape pollen fermented by S. cerevisiae at days 1–8. d The coating on the pollen surface was removed, exposing the germinal apertures and porous exine. e The germinal aperture opened up while the content remained intact. f Similar to e, where three germinal apertures further opened up. g, h Some bond structures were observed in the interior of the pollen. i The exuviae separated itself from structure was destroyed