Radicle and plumule are two essential parts of an embryo plant but they are both different from each other. The experts at have summarised these differences for an easy understanding. To understand this difference between radicle and plumule, we must first understand the process of their origin which begins from a seed. A seed is an important part of flowering plants as it plays a crucial role in the life cycle of these plants.
Every seed contains an embryo that turns into a plant after germination. For the embryo to grow into a plant it must receive all the ingredients needed for its growth like warmth, sunshine, moisture, and nutrient-rich soil. The young plant that germinates or grows from the seed has three primary parts; roots, shoot, and embryonic leaves.
The main difference between plumule and radicle is that while plumule is the embryonic shoot of this seedling, the radicle is the embryonic root. The embryonic leaves are called cotyledons. Both plumule and the radicle are present inside the seed and are joined to the cotyledons.
The Radicle
After germination, the first part of the embryo that grows from the seed is called the radicle. It is an embryonic root of the seedling and later grows on to become the root of the plant. The radicle grows from the micropyle of the seed and develops further down into the soil. As it grows into the soil, it starts to absorb water from it for the growth and development of the embryo. After the emergence of the radicle, the plumule comes out from the seed. It supports the cotyledons and performs photosynthesis, a process that produces food required by the plant for its growth.
There are two types of radicle: antitropous and synchronous. They are different from each other because of the direction of their growth. When the radicle grows away from the hilum, it is known as Antitropous and when it grows towards the hilum, this type of radicle is known as synchronous.
The Plumule
The primary shoot that comes out of the embryo in the seed is the plumule. This plumule later develops into the first leaves of the seedling and is found above the cotyledons during the germination process. The growing tip of the tiny shoot called epicotyl is the part that is known as the plumule. Epicotyl develops into leaves, stems, and flowers as the plant grows.
The process of germination of the seed can be classified into two parts: epigeal germination and hypogeal germination. Epigeal germination is when the plumule appears after the cotyledons have grown above the ground. Hypogeal germination occurs when the plumule grows above the soil while the cotyledons are below the surface of the soil.
Most of the plumules are conical in shape and as cotyledons start to store food, the plumule starts to become small. Sometimes the seed stores less food and in such a scenario, the plumule becomes large and grows well-formed leaves. These leaves then capture more sunlight to perform photosynthesis.
Let’s look at some key points that differentiate between plumule and radicle.
Difference Between Radicle and Plumule
|
Criteria |
Plumule |
Radicle |
|
Part of the plant. |
It is the embryonic shoot. |
It is the embryonic root of the plant. |
|
Timing of emergence |
Plumule comes out after the radicle. |
Radicle is the first to appear from the seed, followed by the plumule. |
|
Future growth |
Plumule grows on to become the shoot of the plant, into its stem and leaves. |
The radicle grows to become the root system of the plant. |
|
Growth direction |
Plumule grows upwards, away from the soil. |
Radicle grows down further deep into the soil. |
|
Color |
Plumule is not as white as the radicle. |
Radicle is whiter in color than the plumule. |
|
Function |
The function of plumule is to perform photosynthesis that helps the plant is producing food for itself. This leads to the rapid growth of the plant. |
The function of the radicle is to absorb water from the soil for the growth of the embryonic plant. |
|
Phototropic |
It is negatively phototropic which means that it grows away from the sunlight. |
It is positively phototropic which means that it grows towards sunlight. |
|
Shape |
Plumule is a bud-like structure that is sometimes conical in shape. |
Radicle had an elongated shape. |
|
Hydrotropic |
It is negatively hydrotropic. |
It is positively hydrotropic. |
One of the essential factors that help to differentiate between radicle and plumule is that they both grow into different parts of the plant.