[Light-color and differentiation of plastids in cell cultures of Nicotiana tabacum var. "Samsun"].

Dark grown cells in cultures of Nicotiana tabacum var. "Samsun" contain numerous small plastids with starch granules and without any detectable traces of pigments. The submicroscopic structure of these plastids consists of only a few isolated thylacoids, some vesiculi, and tubuli. Prolamellar bodies, characteristic of plastids in dark grown leaves, were not observed. In light the cells start to synthesize chlorophyll and the plastids are transformed into photosynthetic active chloroplasts which possess grana composed of stacks of 4-8 lamellae. It has been shown that this transformation is - in contrast to the development of the chloroplasts in leaves - caused only by the blue region of the visible light.