The plumule is the part of the embryonic structure found within the seed of a plant. It is a bud-like structure that serves as the precursor to the shoot system of the plant. The plumule in plants consists of the embryonic shoot apex, which contains meristematic tissue capable of giving rise to the plant’s stem, leaves, and other aerial parts. In this article, we will look into the meaning, location, features, and functions of plumule.
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What is Plumule?
The term “plumule” originates from the Latin word “plumula,” meaning “a little feather,” which describes the delicate and complex nature of this embryonic structure. The plumule refers to a bud-like structure that is the rudimentary shoot apex or embryonic shoot found within the seed embryo of a plant. It represents the precursor to the plant’s shoot system and develops into the leaves, stem meristem, and, potentially, the apical bud.
Location of Plumule
The plumule is located at the upper end of the embryo. It is positioned in the upper side of the seed and, upon favorable conditions, emerges first from the seed coat, growing upward toward the light. The plumule develops into the shoot of the plant.
Diagram of Plumule
A well-labeled diagram of plumule is given below:
Structure of a Seed
A typical structure of a seed and its parts are given below:
- The Embryo: The embryo is the young, developing plant contained within the seed and is protected by the seed coat. It comprises the plumule (embryonic shoot), radicle (embryonic root), and one or more cotyledons (seed leaves).
- The Endosperm: The endosperm is the tissue that surrounds the embryo and serves as a nutrient reservoir for the developing seedling. It contains stored carbohydrates, proteins, and lipids, providing energy and nutrients to support early growth and development.
- The Seed Coat (testa): The seed coat, also known as the testa, is the outermost covering of the seed. It serves as a protective barrier, protecting the embryo and endosperm from mechanical damage, desiccation, and pathogens.
Plumule in Monocot and Dicot Seeds
In both monocotyledonous (monocot) and dicotyledonous (dicot) plants, the plumule is the embryonic shoot apex within the seed embryo. However, there are some differences in the structure and characteristics of the plumule between monocots and dicots.
Plumule in Monocot Plants
In monocots, the plumule is located at the upper end of the embryo. Monocot seeds have a single cotyledon. The plumule in monocots is also encased in a protective sheath called the coleoptile. During germination, the plumule of monocots gives rise to the shoot system, including the stem and leaves.
Plumule in Dicot Plants
In dicots, the plumule is also located at the upper end of the embryo, adjacent to the two cotyledons. Coleoptile is absent in dicot seeds. Like monocots, the plumule of dicots is responsible for initiating the growth of the shoot system during germination.
Features of Plumule
The plumule has several distinctive characteristics that set it apart from other parts of the seed embryos. These are:
- Embryonic Shoot Apex: At its core, the plumule comprises the embryonic shoot apex—a region of undifferentiated cells capable of giving rise to the shoot system of the mature plant.
- Embryonic Leaves and Photosynthesis: The plumule contains immature leaves, known as cotyledons or seed leaves. These embryonic leaves serve as the first photosynthetic organs of the emerging seedling.
- Meristematic Tissue: The plumule contains actively dividing meristematic cells, which leads to the development of the shoot apex.
- Phototrophism: Since the plumule develops into the shoot, it shows positive phototrophism and grows towards light.
- Geotrophism: Since the plumule shows against gravity to form the shoot, it is said to have negative geotrophism.
What is the Function of Plumule?
Function of plumule in seed include include:
- Initiation of Shoot Growth: Upon germination, the plumule gives rise to the embryonic shoot system, which eventually develops into the stem, leaves, and reproductive structures.
- Photosynthesis: The embryonic leaves within the plumule serve as the first sites of photosynthesis in the emerging seedling, providing energy for growth and metabolism.
- Apical Dominance: The apical bud at the tip of the plumule exerts apical dominance. This refers to the apical or upward growth of the plant and the inhibition of lateral buds. This promotes vertical shoot elongation.
- Developmental Signaling: The plumule secretes hormonal signals and growth regulators that coordinate the development of the shoot system and mediate responses to environmental cues.
Difference Between Plumule and Radicle
The main differences between Plumule and Radicle can be summarized as follows:
|
Features |
Plumule |
Radicle |
|---|---|---|
|
Location |
It is located at the upper end of the embryo. |
It is located at the lower end of the embryo. |
|
Function |
Gives rise to the shoot system and thus has photosynthetic functions. |
It develops into the root system, therefore holding the plant in position to the ground and absorbing nutrients from the soil. |
|
Growth Direction |
The plumule grows upward. |
The radicle grows downward. |
|
Develops Into |
The plumule develops into the shoot. |
The radicle develops into the root. |
|
Who Develops Faster? |
The plumule develops before the radicle. |
The radicle grows after the plumule. |
Conclusion – Plumule: The Part of the Seed Embryo
The plumule is a vital component of the seed embryo and has many essential functions. Plumule develops into shoot. It serves as a precursor to the plant’s shoot and contains the embryonic shoot apex, embryonic leaves (cotyledons), and meristematic tissue. This part of the seed embryo initiates shoot growth, facilitating photosynthesis and the overall development of the plant.
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FAQs on Plumule- The Part of the Seed Embryo
Why is Plumule called the Future Shoot?
The plumule is called the future seed because upon germination it develops into the shoot of the plant.
What is the Difference Between Plumule and Radicle?
The plumule is part of the seed that develops into the shoot while the radicle is part of the seed that develops into the root of the plant.
What is the Difference Between Plumule and Cotyledon?
The plumule is the precursor of the shoot of the plant while the cotyledons are part of the seed that serves as the first photosynthetic leaves of a plant and stores food for the growing embryo.
Which Part of the Seed Develops into the Shoot?
The part of the seed that develops into the shoot is called the plumule.
What is the Plumule Part of the Seed Embryo?
The plumule is a bud-like structure in the seed of a plant that develops into the shoot of the plant.
What is Plumule in Plants?
The plumule in plants is the embryonic shoot located above the cotyledons.
What is Radicle and Plumule?
The radicle is the embryonic root, while the plumule is the embryonic shoot, both essential parts of plant embryos during germination.