1. The initial stages in the growth of a seed to form a seedling. Uptake of water into the dry seed by imbibition causes the seed to expand and the seed coat to rupture. It also triggers metabolic changes that reactivate growth. Enzymes are produced that digest food reserves in the endosperm or seed leaves (cotyledons), and the resulting nutrients are transported to the growing embryo. The embryonic shoot (plumule) and embryonic root (radicle) emerge and grow upwards and downwards respectively. See also epigeal; hypogeal.

2. The first signs of growth of spores and pollen grains.