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It has been reported that at the .outset of germination of Vigna sesquipedalis seeds the decrease in ribonucleic acid (RNA) content in a pair of cotyledons is precisely balanced with the increase in RNA in the seedling axis (plumules+ epi-and hypocotyls +radicle), whereas in the isolated cotyledons from the growing tissues no change in the RNA level takes place (Oota and Osawa, 1). On the other hand, in the hypocotyl at the middle of the germination stage (the definition of the germination stage has been given by Oota et al.) when the supply of cotyledonous reserves including RNA has nearly been exhavisted, net synthesis of protein ceases entirely to proceed and a marked drop In the RNA level occurs, and the drop is almost wholly recovered as a simultaneous sharp rise in the RNA level of the epicotyl (Oota et al.). In contrast to a considerable growth of the hypocotyl in the first half of the germination stage, no significant growth of the epicotyl initiates until the mid-germination stage, i.e., typical epigeal germination. If the epicotyl (together with the cotyledons and the plumules) is then removed, the RNA level of the hypocotyl is maintained almost unchanged thereafter throughout the latter half of the germination stage (Oota and Osawa, unpublished, cf. Oota). These facts appear to be hardly explainable without assuming ready migration of intact or nearly intact RNA molecules in the germ tissues in question.Participation of microsomal RNA in protein sj'iithesis is widely accepted. It is believed to be also the case for the bean hypocotyl where the rate of pro- Physiol. Plant., 12, 1950 [518]