What Is the Difference Between Radicle and Plumule in Structure and Function
Radicle and plumule are two essential parts of an embryo plant but they are both different from each other. The experts at Vedantu 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
One of the essential factors that help to differentiate between radicle and plumule is that they both grow into different parts of the plant.
FAQs on Difference Between Radicle and Plumule in Seed Germination
1. What is the difference between radicle and plumule?
The main difference between radicle and plumule is that the radicle develops into the root system, while the plumule develops into the shoot system of a plant.
- Radicle: Embryonic root that grows downward into the soil.
- Plumule: Embryonic shoot that grows upward to form stem and leaves.
- The radicle appears first during germination, followed by the plumule.
2. What is a radicle in a seed?
The radicle is the embryonic root present inside a seed that develops into the primary root during germination.
- It is part of the plant embryo.
- It emerges first from the seed coat.
- It anchors the plant and absorbs water and minerals from the soil.
3. What is a plumule in a seed?
The plumule is the embryonic shoot of a seed that grows into the stem and leaves after germination.
- It is located above the cotyledons in the embryo.
- It grows upward towards light (positive phototropism).
- It forms the aerial parts of the plant.
4. Which develops first, radicle or plumule?
The radicle develops first during seed germination.
- It breaks through the seed coat.
- Forms the primary root.
- Helps anchor the seedling and absorb water for further growth.
- The plumule emerges after the radicle is established.
5. What is the function of the radicle?
The primary function of the radicle is to form the root system of the plant.
- Anchors the plant firmly in the soil.
- Absorbs water and mineral nutrients.
- Initiates the development of lateral roots.
6. What is the function of the plumule?
The main function of the plumule is to develop into the shoot system, including the stem and leaves.
- Forms branches and foliage.
- Enables photosynthesis after leaf development.
- Supports reproductive structures later in the plant’s life cycle.
7. Where are radicle and plumule located in a seed?
The radicle and plumule are located within the embryo of a seed.
- Radicle: Found at the lower end of the embryo, near the micropyle.
- Plumule: Located above the cotyledons.
- Both are protected by the seed coat before germination.
8. How do radicle and plumule grow during germination?
During germination, the radicle grows downward while the plumule grows upward due to directional growth responses.
- Radicle shows positive geotropism (grows towards gravity).
- Plumule shows negative geotropism and positive phototropism (grows away from gravity and towards light).
- This ensures proper root and shoot development.
9. What are the similarities between radicle and plumule?
Both radicle and plumule are embryonic structures that form essential parts of a new plant.
- Both are components of the embryo inside the seed.
- Both remain dormant until germination begins.
- Both are vital for the formation of a complete seedling.
10. Can you give an example of radicle and plumule in dicot seeds?
In dicot seeds like bean or pea, the radicle forms the primary root and the plumule forms the shoot after germination.
- The radicle grows downward to establish the taproot system.
- The plumule grows upward to produce the stem and first true leaves.
- These structures are clearly visible between the two cotyledons in dicot seeds.
