DORMANCY BLOCKS IN SEED DEVELOPMENT AND GERMINATION
In Figure 2, various dormancy mechanisms
are indicated, with their points of action distributed
throughout the various steps of seed development
and, principally, germination, indicating the
concurrent nature of dormancy and germination.
Thus an impermeable seed coat inhibits water
absorption, blocking imbibition, and, in many cases,
the seed coat may reduce oxygen availability to the
embryo (Wareing, 1969). If a seed successfully
completes imbibition, it will normally be
metabolically active (Bewley, 1997). However, a
block to further germination-related activities during
the phase of activation of metabolism may arise in
dormant seeds. Even if this stage is completed
successfully, a mechanical restriction of root
growth may still impose dormancy on the seed, at
the last step in germination