Germination is the resumption of metabolic activity and growth by the seed tissues which starts with the imbibition of water and ends with the protrusion of embryonic roots. The initial step that occurs in germination is absorption of water, involving imbibition and osmosis. The seeds of most of the plants germinate when they are provided with favourable environmental conditions namely moisture, air, suitable temperature and proper sequence of light and dark.
Non dormant viable seeds, when get conditions favourable for germination (viz., adequate water supply, temperature, aeration, etc.) imbibe water through the micropylar pore or the helium of the seed coat. It results in hydration of sub-cellular organelles leading to drastic changes in their organisation. The seed coats are consequently ruptured due to more swelling in the living cells of seeds.