Germination is the first step in growing your luscious lettuce and blooming flowers, and this process happens all thanks to that small seed you first planted. This process is complex and precise, which is why it only happens when the seed is placed in the correct conditions. Otherwise, it simply remains dormant or inactive in the package. As all seeds have different starting requirements, it is easier to generalise which factors all seeds need in order to begin their life.
All seeds need water, oxygen, and a proper temperature to germinate.
(Photo credit: theseedsmaster.com)
Water is taken in by a seed when it begins the germination process via imbibition. Inside the seed, the water hydrates the enzymes already contained within the seed so these can begin to break down the food store inside the seed. Once these food stores are released the seed can use the sugars to release energy for growth. Water also causes a build up of pressure within the embryo’s cells, causing them to elongate and enlarge. This results in the seed coat breaking so the radicle(root) and the plumule(shoot) can emerge from this shell.
Oxygen is another key factor of germination as seeds can only do aerobic respiration if they have an adequate supply of oxygen. Without oxygen, they cannot release the energy from the food stores and therefore are unable to grow.
(Photo credit: morningchores.com)
Finally, a proper temperature is required. For example, some seeds need a period of cold weather before the temperature increases again so they can ensure they germinate after the cold period has passed. This means they are more likely to survive and will not have to endure the cold.