etioplast

A partially differentiated *plastid, 1.5-2.0 μm in diameter, found in the cells of plants that have been kept in darkness (etiolated plants). A three-dimensional lattice, the *prolamellar body, occupies almost the whole of the central region. Etioplasts contain protochlorophyll, which is converted to chlorophyll on exposure to light. Compare proplastid .