Germination is the process by which a seed develops into a seedling. Seeds germinate when they encounter suitable conditions. Some seeds may be dormant for very long periods before they start to develop into new plants. The conditions necessary for germination are:
*Water- which activates the enzymes in the seed.
*Oxygen- which is needed for respiration.
*Suitable temperature- enzymes have a certain range of temperatures in which they are able to operate.
The diagram above shows the germination of dicotyledon seeds. Notice that the germination is hypogeal as the cotyledon stays below the surface of the soil. The epicotyl elongates and forms a hook in the soil rather than growing straight up.
The diagram above shows the germination of monocotyledon seeds. Notice that the germination is epigeal as the cotyledon does not stay below the surface of the soil. Also the shoot does not grow bent but straight up as it is protected by a special sheath- coleoptile.