With the seed, the independence of the next generation of
plants begins. The seed, containing the embryo as the new
plant in miniature, is structurally and physiologically equipped
for its role as a dispersa1 unit and is well provided with food
reserves to sustain the growing seedling until it establishes
itself as a self-sufficient, autotrophic organism. Because the
function of a seed is to establish a new plant, it may seem
peculiar that dormancy, an intrinsic block to germination,
exists. But it may not be advantageous for a seed to germinate
freely, even in seemingly favorable conditions. For example,
germination of annuals in the spring allows time for
vegetative growth and the subsequent production of offspring,
whereas germination in similar conditions in the fall
could lead to the demise of the vegetative plant during the
winter. Thus, dormancy is an adaptive trait that optimizes
the distribution of germination over time in a population of
seeds.