Genome Activation during Seed Germination
Transcriptional events were found to be activated in a stepwise manner when mature wheat seeds were exposed to the optimal germination conditions. Immediate-early, and late transcription products could be distinguished from each other by differences in their nucleotide composition. The immediate-early transcripts appeared in the seed already within the first 3 hours of imbibition and were unusually rich in UMP /65 mol%/. The early transcripts could be characterized as U+G rich. The late transcripts began to appear 12 hours after germination starts and had nucleotide composition similar to that of the total RNA.