Free and membrane-bound ribosomes of the cotyledons of Vicia faba (L.) : II. Seed germination.

During the first few days of germination, the RNA content of the cotyledons remained approximately constant, but the quantity of membrane-bound ribosomes increased. Experiments with orthophosphate-(32)P indicated that these ribosomes were synthesised de novo, and did not originate by the attachment to membranes of pre-existing free ribosomes. This conclusion was discussed in relation to the suggestion that free and membrane-bound ribosomes synthesise different groups of proteins.