1.Embryonic root cells from air-dried seeds ofPisum sativumwith extremely low water content were investigated by electron microscopy in the state of dormancy. The isolated roots were fixed by OsO4-vaporization and embedded in maraglas over ethanol and propylenoxide.2.Compared with water-saturated cells there are specific effects of contrasting. The explanation for these effects is consistent with the present knowledge of OsO4-binding to lipophilic and hydrophilic compounds in the absence of water.3.Organells, cytoplasmatic structures with special functions, and plasmodesms were conserved during dormancy. In spite of considerable shrinkage there is no mechanical damage. The intramembranous space visible in water-saturated cells disappears during dormancy. The boardering unit membrane appears unchanged as a layer 75–80 Å wide.4.The osmiophilic lipid vacuoles, distributed in metabolically active cells in the cytoplasm are in dormant cells arranged along the cell wall.5.In the state of full dormancy the reserve proteins inside the aleuron bodies are in a crystalline sta
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