Hilum vs. Micropyle — What's the Difference?
By Fiza Rafique & Urooj Arif — Updated on May 16, 2024
Hilum refers to the scar on seeds marking where it was attached to the plant, whereas micropyle is a small pore in the seed coat allowing sperm entry during fertilization.
Difference Between Hilum and Micropyle
Table of Contents
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Key Differences
Hilum is a visible scar on the seed coat indicating the point of attachment to the ovary. It is often an elliptical or oval mark. This feature is a sign of where the seed was connected to the plant's placenta. Whereas, the micropyle is a minute opening in the seed coat that facilitates the entry of the pollen tube, which allows sperm cells to reach the ovule during fertilization.
The hilum remains after the seed is detached from the plant, serving as an indicator of where the seed received nutrients. On the other hand, the micropyle’s primary role is reproductive, ensuring that the seed can be fertilized.
The hilum does not play a role in the germination process, acting only as a remnant mark of attachment. Conversely, the micropyle is crucial during germination, allowing water absorption and oxygen entry into the seed, which are essential for sprouting.
In terms of visibility, the hilum is often more conspicuous and easier to spot on the seed surface. The micropyle, however, is typically much smaller and might require closer inspection to identify.
Hilum can vary in shape and size among different plant species, reflecting their unique attachment methods. Micropyle, though always small, also varies in precise location and form, tailored to the seed's specific fertilization needs.
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The hilum marks a physical connection history with the parent plant, signifying a past link. Micropyle represents a functional aspect of seed physiology, emphasizing its role in reproduction and germination.
Comparison Chart
Function
Attachment scar
Fertilization and germination pore
Role in Plant Life
Indicates where seed attached
Allows sperm entry, aids germination
Visibility
Usually conspicuous
Typically small and less noticeable
Variability
Shape and size vary by species
Location and form vary by species
Relation to Parent
Shows past connection to plant
Functional in reproductive process
Compare with Definitions
Hilum
A distinguishing feature on seeds like beans and peas.
You can identify the hilum easily on a kidney bean.
Micropyle
An aperture essential for seed reproduction.
Without a functioning micropyle, the seed cannot be fertilized.
Hilum
The area where the seed was connected to the placenta.
The hilum can be seen clearly on the pea seed.
Micropyle
A pore facilitating fertilization in plant seeds.
Water absorption during germination occurs through the micropyle.
Hilum
The mark left on the seed after separation from the plant.
Each sunflower seed has a small hilum at its base.
Micropyle
A small orifice in the ovule’s surface.
The microscope revealed the tiny micropyle on the seed.
Hilum
A scar on a seed coat indicating attachment to the ovary.
The bean's hilum is an elongated mark on its side.
Micropyle
A small opening in the seed coat for sperm entry.
The micropyle allows the pollen tube to enter the ovule.
Hilum
The scar on a seed, such as a bean, indicating the point of attachment to the funiculus.
Micropyle
A critical feature for the germination process.
The seed's micropyle is vital for starting the growth process.
Hilum
The nucleus of a starch grain.
Micropyle
(Botany) A minute opening in the ovule of a seed plant through which the pollen tube usually enters.
Hilum
The area through which ducts, nerves, or blood vessels enter and leave a gland or organ.
Micropyle
(Zoology) A pore in the membrane covering the ovum of some animals through which a spermatozoon can enter.
Hilum
(botany) The eye of a bean or other seed; the mark or scar at the point of attachment of an ovule or seed to its base or support.
Micropyle
(botany) In seed-bearing plants, a small opening in the integuments of the ovule through which sperm are able to access the ovum.
Hilum
(botany) The nucleus of a starch grain.
Micropyle
(zoology) The hilum of an ovum at the point of attachment to the ovary; any opening in the coverings of an ovum by which spermatozoa may find entrance.
Hilum
(anatomy) A depression or fissure through which ducts, nerves, or blood vessels enter and leave a gland or organ; a porta.
Micropyle
An opening in the membranes surrounding the ovum, by which nutrition is assisted and the entrance of the spermatozoa permitted.
Hilum
The eye of a bean or other seed; the mark or scar at the point of attachment of an ovule or seed to its base or support; - called also hile.
Micropyle
Minute opening in the wall of an ovule through which the pollen tube enters
Hilum
The part of a gland, or similar organ, where the blood vessels and nerves enter; the hilus; as, the hilum of the kidney.
Hilum
(anatomy) a depression or fissure where vessels or nerves or ducts enter a bodily organ;
The hilus of the kidney
Hilum
The scar on certain seeds marking its point of attachment to the funicle
Hilum
A characteristic mark indicating the seed's point of detachment.
The gardener inspected the hilum to ensure the seed's quality.
Common Curiosities
What is the hilum on a seed?
The hilum is a scar on the seed coat that marks where the seed was attached to the ovary.
Is the hilum involved in seed germination?
No, the hilum does not play a role in germination; it is merely a mark of attachment.
Is the micropyle the same in all seeds?
The micropyle can vary in location and size among different plant species but serves the same primary function.
Is the micropyle involved in seed dormancy?
The micropyle itself isn't directly involved in dormancy but is crucial when the seed begins to germinate.
What does the micropyle do?
The micropyle allows sperm entry into the ovule for fertilization and aids in water absorption during germination.
Can you see the micropyle easily?
The micropyle is typically very small and may require close inspection to see.
How can the hilum be used in seed identification?
The shape, size, and position of the hilum can help in identifying seed species.
Why is the hilum important?
The hilum is important as it indicates where the seed was attached to the parent plant, providing clues about the seed's developmental history.
Does the micropyle have a role after fertilization?
Yes, the micropyle helps in water absorption and oxygen intake during seed germination.
Do all seeds have a hilum?
Yes, most seeds have a hilum, although its visibility and size can vary.
How does the hilum form?
The hilum forms as the seed detaches from the placenta, leaving a scar at the attachment point.
Does the hilum have any protective function?
No, the hilum does not serve a protective function; it is simply a mark of detachment.
Can water enter through the hilum?
No, water usually enters through the micropyle during germination, not the hilum.
What happens if the micropyle is damaged?
Damage to the micropyle can impede fertilization and germination, affecting seed viability.
Are there seeds without a micropyle?
No, all seeds have a micropyle as it is essential for fertilization and germination.
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Written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
Co-written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
