title: The ultrastructure and ontogeny of pollen in Helleborus foetidus L. IV. Pollen grain maturation.
mesh_terms: D002462:Cell Membrane; D002467:Cell Nucleus; D002473:Cell Wall; D003594:Cytoplasmic Granules; D004721:Endoplasmic Reticulum; D002479:Inclusion Bodies; D008854:Microscopy, Electron; D008928:Mitochondria; D008938:Mitosis; D010944:Plants; D011058:Pollen / Q000166:cytology* / Q000254:growth & development; D012270:Ribosomes