The process by which the embryo grows out of the seed coat and establishes itself as a seedling is called as the germination. The seed germination and the seedling growth involve four stages. They are:
Imbibition of water by seeds.
The enzymes get hydrated and become active.
The turgor pressure of the cell increase and the cell enlarge.
The emergence of radicle, plumule and the growth of seedlings.
The uptake of water by the dry seeds occurs by the process of imbibition. As the seed absorbs the water, the enzymes and food supplies become hydrated. These enzymes become active there by the metabolic activities increases. The seed coat breaks and the radicle emerge out first. The radicles which later give rise to the root and then plumule emerges out which forms the shoot system which completes the growth of the seedling.