Abstract
Incorporation studies with radioactive precursors showed that synthesis of protein and RNA is initiated in germinating embryos of rye within the first hour of imbibition of water. By polyacrylamide-gel fractionations of radioactive nucleic acid components, the appearance of products of transcription of the genome was shown to follow the sequence: heterogeneous (ribonuclease-sensitive) RNA, 4S and 5S RNA by 20min, 31S and 25S rRNA by 40min, and 18S RNA by 60min. "Fingerprint' analysis of T1-ribonuclease digests show that all the large oligonucleotides present in 25S and 18S RNA are present in the 31S species, indicating that 31S RNA is the precursor rRNA molecule to both 25S and 18S RNA. The importance of these early RNA syntheses and in particular the possible template function of the heterogeneous RNA is discussed in relation to the concept of long-lived mRNA and the coding for protein synthesis in the first hours of germination.