Seed germination is something that most people are not familiar with. But, it is a fundamental process to plants’ life cycle, which is vital for developing new strains of plants.
If you don’t germinate your seeds, you will not grow your plants.
This blog will give you an overview of the seed germination process.
About Seed Germination
Germination is the process of seed coming to life. The seed is dormant and contains all the nutrients necessary to grow into a plant.
When conditions are right, the seed begins to grow, and the embryo inside starts to develop. The seedling will emerge from the soil and grow into a new plant.
The sprouting of a seedling from an angiosperm or gymnosperm seed is a typical example of seed germination.
What are the Stages of Seed Germination?
The following steps are followed to complete the seed germination process:
Phase 1: Imbibition Process
Imbibition, or the absorption of water by the dry seed, is the initial step in seed germination.
Imbibition causes the seed to expand as the cellular contents rehydrate.
The swelling happens quickly and with a lot of force. It causes the seed coverings to break, allowing the radicle to emerge as a primary root.
Phase 2: Activation of Metabolism
This time, the water absorbed by the seeds activates a particular protein called enzymes.
The activation of enzymes kicks off the growth process, and the seed’s internal physiology is activated, and it begins to respire, make proteins, and digest the stored food.
Phase 3: Radicle Protrusion
When a seed germinates, the primary root, or radicle, is the first organ to develop. It anchors the seedling by growing downward into the earth.
The radicle is starting to expand by the seeds to access the water underground after activating enzymes from the seeds.
Phase 4: Growing Stage
After that, the shoots, or above-ground growth, arise.
The seed propels a shoot up to the surface, where it will sprout leaves to harvest solar energy.
Conditions For Seed Germination
When a seed is planted, the conditions of the environment will determine if and how well the seed germinates.
The rate of germination depends on many factors, including water, oxygen, temperature, and light exposure.
Let’s look at why these factors are important in seed germination.
Water
The germination of seeds necessitates a lot of water. Some seeds are dehydrated and require a significant amount of water compared to their dry weight.
The importance of water in seed germination cannot be overstated. It aids in the critical processes of protoplasm by supplying hydration dissolved oxygen for the forming embryo, softening seed coatings, and increasing seed permeability.
It also aids in seed rupturing and converting insoluble food to soluble form for translocation to the embryo.
Light Exposure
Seed germination can also be affected by light. Many seeds do not germinate until they are exposed to sunlight, while others sprout in darkness.
However, this depends on the sort of seeds you want to germinate.
Photoblastic seeds are those that respond to light to germinate.
Positive photoblastic, negative photoblastic, and non-photoblastic seeds are the three types of photoblastic seeds.
Positive photoblastic seeds, such as lettuce, tobacco, and mistletoe, do not germinate in the dark and must be exposed to sunshine (even if just for a short time) to grow.
Negative photoblastic seeds such as onion, lily, Amaranthus, and Nigella do not germinate when exposed to sunshine.
While non-photoblastic seeds germinate regardless of whether light is present or not.
Temperature
One of the most critical elements impacting seed germination is temperature.
Most seeds prefer a temperature of around 77 degrees Fahrenheit. On the other hand, some seeds can germinate in a more extensive range of temperatures, while others require highly particular circumstances to grow.
The quantity of temperature required by seed is determined by its species.
Seeds from the sunflower family, for example, may germinate at temperatures as low as 70 to 85 degrees Fahrenheit.
Others, such as apple seeds, require around 75 degrees Fahrenheit to sprout.
Other conditions, such as humidity and air circulation, can affect how well a seed germinates in addition to the temperature.
High humidity, for example, might cause mildew to form on the seed, whereas stagnant air can dry up the embryo and cause it to die.
Oxygen
It is a critical and necessary source of energy for seed growth. It is essential for metabolism by the developing seed and is used as part of aerobic respiration until it can grow its green leaves.
The holes of soil particles contain oxygen, but if the seed is buried too deeply, it will be deprived of it.
Factors Affecting Seed Germination
The conditions necessary for germination vary from species to species, but some general factors affect germination. These are some of them:
Internal Factors
One of the internal factors that might affect the germination of the seed is called Seed Dormancy.
It is a condition in which seeds cannot germinate, even when the conditions are ideal.
The seed coat, resistant to water and gases, inhibits water intake and oxygen exchange during seed dormancy.
Seeds with immature or underdeveloped embryos do not germinate.
Plant growth regulators, found in some seeds, prevent seed germination. At the same time, some seeds take longer to germinate than others.
External Factors
Water
Seed germination is affected by a lack of or increased supply of water.
Temperature
The temperature has an impact on the seed’s growth rate and metabolism.
A temperature below the moderate threshold delays seed germination and encourages fungal growth in some circumstances.
In some circumstances, the seed may halt germination if the temperature rises over a modest threshold.
Oxygen
In the process of germinating, seeds take in a lot of oxygen and release the energy they need to grow. As a result, a lack of oxygen impacts seed germination.
Conclusion
Seed germination is a vital process for plants to grow and produce offspring.
By understanding the different factors that influence seed germination, gardeners can create an environment to help their seeds germinate successfully.
Related Articles: