Long-lived Messenger RNA and its Relationship to Protein Synthesis During Germination of Pea (Pisum sativum L.) Seeds

Synthesis of both protein and RNA is initiated very early in germination in the embryo axes of pea seeds. The early RNA synthesis involves all three types, although there is some evidence for preferential synthesis of mRNA in the first few hours after the onset of imbibition. In addition to newly synthesized mRNA, the embryo axis also contains long-lived mRNA. The amount of this long-lived mRNA declines markedly during the first 20 h of germination. Synthesis of both protein and RNA is initiated very early in germination in the embryo axes of pea seeds. The early RNA synthesis involves all three types, although there is some evidence for preferential synthesis of mRNA in the first few hours after the onset of imbibition. In addition to newly synthesized mRNA, the embryo axis also contains long-lived mRNA. The amount of this long-lived mRNA declines markedly during the first 20 h of germination. Results from in vitro and in vivo protein synthesis experiments and from studies of polysome formation suggest that much of the long-lived mRNA present in the embryo axis does not direct protein synthesis. The increase in the rate of protein synthesis during germination is thus dependent on recruitment of newly synthesized mRNA molecules.