Radicle Extension and the Completion of Germination
With few exceptions, radicle extension through the structures
surrounding the embryo is the event that terminates
germination and marks the commencement of seedling
growth. This extension may or may not be accompanied by
cell division. Two discrete phases of DNA synthesis occur in
the radicle cells after imbibition (Figure 1). The first takes
place soon after imbibition and probably involves the repair
of DNA damaged during maturation drying and rehydration
as well as the synthesis of mitochondrial DNA. DNA
synthesis associated with postgerminative cell division accounts
for the second phase (Figure 1 ; Zlatnova et al., 1987;
Osborne and Boubriak, 1994).