The beginning of the growth of a plant is from a seed. This is the first stage when the seed germinates to become a seed. Let’s start by taking a closer look at the structure of a seed.
Inside a seed, what is the stem that will become the first branch of the plant and what is the root that will cause the formation of the root.
Seeds also have cotyledons that act as a food store for the new plant until the new plant can photosynthesize, and also have a seed coat that forms a protective layer.
If we look at the cross section of this seed, you can see the stem, root, cotyledon and a seed coat around.
As germination progresses, you can see a root system develop and the first stem and leaves grow from the same stem. A few days later, shoots emerge from the cotyledons, which develop into leaf-like structures. These are known as seed leaves, are green and can carry out photosynthesis until the first true leaves develop from the stem. By looking at all three stages side by side, you can see the changes over time.
So what do seeds need to germinate?
Let’s start with the assumptions that people often make, not all of which happen to be true. First, we usually grow seeds by putting them in soil, so if you plant a seed and water it, maybe the seeds need soil to germinate, but water seems more reasonable. All plants need sunlight, so perhaps germinating seeds need sunlight too. Photosynthesis requires carbon dioxide, so it’s a reasonable guess, plants need to breathe, so maybe seeds need oxygen to breathe.
Let’s take a closer look at each of these ideas:
First the soil
Here are some seeds that have been placed on moist tissue for a few days and are germinating without any soil. No, soil is not required for germination.
Water? Yes, it is necessary for germination, dormant seeds are dry, but the chemical reactions for growth and development can only take place in solution when the molecules are free to move.
How about sunlight? Well remember that seeds cannot photosynthesize, instead they get their food from the cotyledons, moreover, seeds often germinate when buried in the soil and in total darkness. , so generally there is no need for sunlight.
Next carbon dioxide, well we know this is needed for photosynthesis, but think again about a seed that soon germinates, there are no leaves and often no light, so there is no photosynthesis, so there is no need for it to germinate. It is not carbon dioxide.
What about oxygen for breathing? Yes, the need for oxygen is necessary for growth and development. Energy and this energy is released through breathing. Remember that this type of respiration requires glucose and oxygen, glucose is already supplied in the seed from the cotyledons, but for successful germination, oxygen must be supplied from the air.
There is one more thing “hot temperature”, remember that almost all chemical reactions in living organisms require enzymes for reactions involving enzymes. It cannot be so hot that the enzymes are destroyed or so cold that the molecules move too slowly, so we need warm temperatures for successful germination.
The main summary of this article is that germination is the beginning of the growth of a plant from a seed, and the following three factors are required for seed germination: