Chloroplast development in green barley leaves transferred to darkness

Evidence is presented that immature barley chloroplasts developing normally from proplastids in light-grown plants continue to synthesise thylakoids when the plants are transferred to darkness. This observation is consistent with the finding that normal light-grown barley plants continue to synthesis chlorophyll when transferred to total darkness (Popov and Dilova 1969, Adamson 1982). A physiological role for the light-independent protochlorophyllide reductase in higher plants is suggested.