It’s a common misconception that seeds are the first stage of reproduction and birth of a new plant, and that couldn’t be further from the fact. While seeds are an important component of reproduction, what matters more is what’s inside them.
Seeds can be considered containers. Whereas the real foundation of the birth of a new plant is the embryo. In this article, we’ll discuss what a plant embryo is, its importance, and much more! So, let’s get right into it.
What Is Plant Embryo
The plant embryo is essentially the roots, leaves, and stem of the plant in its earliest possible form. A plant’s embryo is mainly contained within the seed of the plant. However, this isn’t necessarily true for all plants, as some may reproduce without a seed.
Importance Of Plant Embryos
The embryo activates and triggers the seed to germinate when certain conditions are met. Slowly, the seed turns into a seedling and then a plant.
To sum it up, the plant embryo acts like a “Starter Kit”. The embryo is capable of detecting external stimuli. When it detects the presence of adequate oxygen, water, and specific minerals, it triggers germination. This is when the seed starts absorbing the endosperm.
Without the embryo, the seed would’ve been an empty shell incapable of growing into a new plant. This is why it’s considered more important than the seed in the case of plant reproduction.
The Process of Plant Embryo Development
The procedure of plant embryo development is called embryogenesis in short. Embryogenesis is triggered in the ovule of a plant from either single or double fertilization.
Beginning of Embryogenesis
This process leads to the creation of two different components, the endosperm and the zygote. The endosperm later develops into the seed under suitable circumstances.
Whereas the zygote goes through a cell division process that results in two different cells, the basal and the apical cells. These two cells are responsible for creating the polarity in the ovule.
Of the two, the apical cell contains most of the cytoplasm and is located at the top. Through further cell division, this cell gives birth to the cotyledons, hypocotyl, and apical meristem.
On the other hand, the basal cell, which is located at the bottom, divides and creates the hypophysis and suspensor. The basal cell contains a large vacuole and usually is larger than the apical cell.
After this, the embryo goes through the eight-cell and sixteen-cell division stages. In the third stage of growth, the embryo takes a spherical shape. This is why this is known as the globular stage.
The globular stage is one of the most important ones as the meristematic tissue is developed in this phase. The growth of two other important components, the procambium and ground meristem, is initiated in this stage.
Next, it goes through the heart stage, which is more of a transition form. The cotyledons are formed, and they elongate throughout this stage. It’s called the Heart stage because most plants contain two cotyledons at this stage, and they give a heart-like appearance.
In this stage, the cotyledons and the axis continue to elongate further. One of the key changes in this stage is the shortening of the suspensor complex through the termination of some of its parts.
The main reason behind this shortening is making adequate space for the embryo to mature. Throughout this phase, the suspensor shortens and disappears eventually while the embryo matures.
The maturation falls under the postembryonic development stage, as the embryo is more or less mature by this. In this phase, the embryo stores essentials such as starches, oils, and proteins.
These essential supply energy during germination and growth of the seed. Furthermore, the seed hardens in this stage, which makes it suitable for survival.
The last stage of embryogenesis is called dormancy, and this is where the embryo stops growing. What makes this phase stick out is that even if the seed is kept under perfect conditions, it won’t germinate.
To force the seed to germinate or to break the dormancy, some special actions must be taken. For example, if the seed is too thick, the external coating of the seed must be stripped off through a process known as scarification.
In other cases, the seed is exposed to smoke or cold for breaking the dormancy. Either way, breaking the dormancy is one of the crucial factors for germination.
How Does the Environment Affect Plant Embryo Development?
The environment has a huge effect on plant embryo development, especially in the dormancy phase. Multiple environmental factors can affect a seed’s germination.
These are mainly drought, cold, saline water, and heat. However, whether these will influence the dormancy period or not depends strictly on the type of seed.
While some seeds germinate faster in a cold climate, other seeds break dormancy under heat.
Why Is Understanding Plant Embryo Development Necessary
Plant embryo development is an important concept, and it’s important to understand it for many reasons. A solid grasp of this topic can help us in a multitude of ways.
For starters, understanding how a plant’s embryo develops can help researchers come up with new ways of irrigation and cultivation. With the acquired knowledge, it’s possible to tweak the existing methods for a faster and better harvest.
Moreover, researchers can edit the genome of plants to enhance their output as well as durability. Furthermore, it’s also possible to make plants resistant to certain diseases.
By understanding the germination process of a certain plant, it’s possible to make a new species out of it that’s more refined and yields higher output.
Hopefully, our detailed discussion on embryogenesis and how to plant an embryo might be affected by environmental factors satisfied your curiosity.
Now that you know the concept, we highly recommend picking a handful of plant species and learning how embryogenesis works for them.