Earlier work on germination has always taken an
extended view of the process of germination, The
process was regarded as commencing when tine mature
dry seed is subjected to suitable conditions and
ending when the young seedling appeared. In most
of the earlier work the appearance of the seedling,
was taken in the soil and this of course also included
establishment of the plantlet.
It is clear that the greater part of the process
discussed in these researches includes growth purely
and not germination in a stricter sense. Work in
this laboratory has tended to narrow the definition
and regard germination as taking place in three
overlapping stages with a comparatively smooth
progression from the dry seed to the activated embryo.
In the order of their appearance the three stages
may be said to be (Nelson and Macsween 1933):-
a) Hydration of the colloids of the tests of the
b) Water intake by an osmotic mechanism through the
hydrated tests which acts as a semipermeable
c) "Vital" reactions involving energy release, and
movement and reorganisation of plastic materials
- more crudely respiration and growth.