Germination

The growth of a seed into a new plant or seedling is called  germination.

Germination   is the sprouting of a seed after it has been planted in the ground and has been dormant for a certain period of time .

For plants and fruits that reproduce through seeds and pollen, the seeds eventually grow into young plants through the process of   seed germination .

When seeds are planted, they remain dormant until conditions are right for  germination.

For  germination  to occur, several conditions must be met, such as the proper amounts of water, oxygen, temperature, and light. When these conditions are met, the seed begins to enlarge as it absorbs water and oxygen. The seed coat splits open and a root or radicle emerges from the seed, which is followed by an aerial part of the plant. This early stage of a plant’s development is  germination .

Germination  in plants is the process by which a dormant seed begins to sprout and grow into  a seedling under the right growing conditions.

More about Germination

Germination   is a process in which a seed or spore awakens from dormancy and begins to sprout .

Many people study this process in action in science class in their childhood, growing seeds like beans or peas in the classroom, and a quick trip to the countryside is likely to reveal at least a few examples, especially in the spring.

This process is critical to the growth of new factories, and it can be quite fascinating to watch from start to finish.

Both seeds and spores experience periods of dormancy. Dormancy is often influenced by external factors such as temperature and light availability, with seeds and spores being programmed to remain dormant if conditions are unfavorable for growth.

People can manipulate these conditions to force  germination or dormancy .

The dormancy stage   can also be programmed into the seed or spore, which means that it will not germinate under favorable conditions until the internal clock determines that the time for growth has arrived.

In order to sprout, light levels, oxygen availability, temperature and humidity levels must all be adequate.

The end of  germination or dormancy  triggers a cascade of reactions that ultimately ends in the projection of roots and radicles or the growing tip of the developing plant.

The radicle forces its way out of the protective layer and climbs towards the light.

In the early stages, nutrients stored in the seed or spore provide the energy the young plant needs, and in the later stages, the roots extend into the soil, collect nutrients, and the plant begins to photosynthesize the energy as it reaches the surface. from soil.

Seeds can remain  dormant  for a long time, depending on the natural resources  by man. In fact, in these areas, not only species, with some examples as old as 10,000 years successfully germinating.

As a general rule, the older the seeds, the less likely they are to germinate. Small, wilted seeds are also less likely to grow. For gardeners and farmers, the process is critical, as lack of germination can become a serious problem.

Gardeners with seeds sitting around who are curious as to whether or not the seeds will grow can do a simple test by taking ten seeds and sealing them in a plastic bag with a damp paper towel. The bag can be kept at room temperature for one to two weeks to see if the seeds sprout. If eight to ten germinate, the seeds are in good shape and can be planted normally. If six to seven seeds germinate, the seeds should be packed together when they are planted, and if five or less sprout, the seeds should be discarded.

While this test works well for many common types of seeds, it’s important to remember that all seeds have their own specific germination period, which can vary by months or even years. Also, some seeds naturally need to be scarred or treated with hot water before they will germinate, so gardeners should do a little research on seeds before testing them to determine their natural growing conditions.

Types of Germination

Germination can be of two types: epigeal and hypogeal.

Epigeal germination : the cotyledons rise above the ground. It is typical of dicotyledons .

Hypogeal germination : the cotyledons remain in the soil. It is typical of monocots .

Cotyledons are the embryonic leaves of plants, formed by the seed and important for the initial development of plants. They are the first leaves that emerge from the embryo.

The number of cotyledons in the seed classifies plants into monocots and dicots.

Factors Affecting Germination

For germination to occur, certain conditions are necessary that depend on environmental factors and the seed itself.

The main factors that affect germination are:

• water availability
• Oxygen
• Light
• Temperature
• Seed coat permeability
• Chemical substances
• seed dormancy

Among all the factors, water is the most determinant for germination. Soaking, the process of capturing water, hydrates the tissues and intensifies the metabolic activities necessary for the resumption of growth of the embryonic axis.

Despite the importance of water, its excess causes a decrease in germination, as it prevents the penetration of oxygen.

Naturally, seeds germinate as soon as they encounter favorable environmental conditions. However, other seeds need to overcome the dormancy state before germination.

Germination and seed dormancy breaking also depend on the action of plant hormones , such as gibberellins.

Germination Phases

Germination can be divided into three phases: imbibition, induction of growth and growth of the embryonic axis.

Soaking Phase

The imbibition phase consists of capturing water, which causes the initial wetting of the tissues closest to the surface.

The amount of water absorbed must be sufficient not only to initiate germination, but also to ensure that the process proceeds to completion.

Growth Induction Phase

At this stage there is a reduction in water intake. New tissues are formed and metabolism is activated.

Embryonic Axis Growth Phase

The growth phase comprises the process of cell expansion and the rupture of the integument with the protrusion of the radicle (embryonic root). The radicle is the first part to emerge from the seed.