Behavior of pollen from insect-pollinated angiosperms in PDs. (A–E)Paeonia suffruticosa and (F-J)Orychophragmus violaceus pollen grains tended to clump together, remaining visible on the surface of PDs, and could not enter the ovule. O, ovule; P, pollen grains; Mi, micropyle. Scale bars = 200 μm.
Jin et al. BMC Plant Biology 2012 12:59 doi:10.1186/1471-2229-12-59