When the seed absorbs water the embryo is activated and produces gibberellins which switch on genes that code for amylases and proteases to break down food stores in the seed. In dicot seeds, the food stores are cotyledons and in monocots the food store is the endosperm. The embryo plant then produces ATP and grows and breaks through the seed coat (testa).ABA may act as an antagonist to gibberellins so the relative proportions of both hormones determine whether or not a seed will germinate.