The process by which the dormant embryo of seed resumes active growth and forms a seedling is known as germination. The initial step in germination process is the uptake of water and rehydration of the seed tissues by the process of imbibition. The first visible sign of germination is the emergence of the radicle from the seed. But this event is preceded by a series of biochemical reactions. Imbibition of water causes the embryo within seed to produce $\alpha$- and $\beta$-amylases. These enzymes hydrolyze the starch stored in endosperm into glucose which is necessary for use both as a respiratory substrate and as a source of carbon skeletons of the molecules needed for growth.