Two Bible verses seem to indicate that ancients believed germination was the death of a seed, and a resurrection or rebirth of that seed into a plant:
Unless a grain of wheat falls into the earth and dies, it remains just a single grain; but if it dies, it bears much fruit. (John 12:34)
What you sow does not come to life unless it dies. And as for what you sow, you do not sow the body that is to be, but a bare seed, perhaps of wheat or of some other grain. (1 Corinthians 15:36-37)
Context: In the first instance, Jesus is using germination as an image for his upcoming resurrection, and in the second, Paul is using it as a metaphor for the post-death resurrection Christians experience as a consequence of Jesus' sacrificial death.
Textual background: The two writings are the Gospel of John and Paul's first epistle to the Corinthians. Both of them are written in Koine Greek and in the city of Ephesus, probably in the first century. John was likely written between 90 and 110, and 1 Corinthians between 50 and 55. The author of John is traditionally said to be the apostle John, a Jew from Galilee, though scholars generally deny that much is known of the actual author, besides that he is quite literate. 1 Corinthians was written by Paul, a learned Pharisaic Jew from Tarsus with training in Greek rhetoric.
I only mention this background because in my mind there are three potential sources of their common germination illustration: a Jewish precedent, a Greek academic precedent (or a more local Turkish or Palestinian academic precedent or something), or something in the oral Christian tradition. The second, and maybe the first, would be on-topic to mention here, if I understand guidelines correctly.
Is there an academic, protoscientific precedent within the Greek academy that describes germination in terms of death and rebirth?