What is seed germination?
Seed germination is one of the most important phases in the life of plants. The seed is the basic building block for plants. Although a seed appears as a tiny capsule, it contains a potential life or embryo within it. In fact, even that seemingly life-less seed has reserve supplies of food and water that keeps the embryo within it alive. Without favorable environmental conditions, the seed is inactive or said to be in a quiescent state. When external conditions become favorable the metabolism process is initiated and the seed will germinate. It is then ready to grow into a plant.
So simply put, germination is a process that includes various changes that occur from the instance the inactive seed is provided with externally favorable conditions to the time when it sprouts into young seedlings.
Seed
So, what happens during germination?
Various changes take place during germination. It is during the process of germination that the embryo of the seed starts to develop. The germination process can be divided into two steps:
Imbibition: This is the first step in the seed germination process in which the seed absorbs water. When water has been provided to the seed, an externally favorable environmental condition is created and the seed becomes active because its constituents are hydrated. Subsequently the seed swells up. It swells up to a point which causes the coating of the seed to crack. And from this opening in the seed, life springs out in the form of a root.
Respiration: When externally favorable conditions are provided to the seed, the metabolic process is triggered, initially in the absence of oxygen. Over a period of time, metabolism processes take place in the presence of oxygen.
Thus in the process of germination, the seed sprouts into a seedling, with the roots forming first and then the leaves forming next. The germination process comes to an end when the seedling has used up all the stored reserves of food it had as a seed. The end of germination marks the beginning of establishment phase.
So, what are the requirements for seed germination?
The essential external factors for germination are:
- Water: Water is crucial for the germination of the seed. Water softens the coating. When this water is absorbed by the seed, it causes the seed to swell and then cracks open to start the process of germination
- Temperature: The soil or compost temperature required by various seeds to germinate is different. The temperature range is crucial since the seed will not germinate above or below that range. A temperature range of 60 degree F to 75 degree F is ideal for many varieties of seeds to germinate. However, there are seeds that will germinate in cooler soil temperatures
- Oxygen: It is crucial to the metabolism process and provides energy to the seedling. Burying the seed deep inside the soil or water logging the soil may prevent seed germination due to lack of oxygen
- Light or darkness: Some seeds require light whereas some seeds germinate regardless of exposure to light. The former type is called Photoblastic and the latter is called Non- Photoblastic
Thus, in order to increase the likelihood of seed germination or the germination rate, it is important to provide favorable environmental conditions to that particular group of seeds
Seed Germination
Eddie enjoys gardening and the challenges it provides. He is particularly interesting in growing vegetable garden seeds and often uses a seedling mat to help them along.