title: Nucleus and endoplasmic reticulum in differentiating root protophloem of Nicotiana tabacum.
mesh_terms: D002454:Cell Differentiation; D002467:Cell Nucleus; D004721:Endoplasmic Reticulum; D008854:Microscopy, Electron; D008928:Mitochondria; D059828:Plant Cells; D012270:Ribosomes