Q.What is Coleorrhiza?
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Seed Structure Terminology – A First Look
Think of a seed as a tiny, self-contained survival kit. A plant makes a seed to send its offspring out into the world, equipped with everything needed to travel, wait, and eventually sprout into a new plant. The terminology around seed structure is simply the names we give to the parts of that kit.
The Three Essential Parts
Every seed, from a mustard seed to a mango seed, has three basic components. You can remember them as the baby, the lunchbox, and the coat.
- Embryo – This is the baby plant itself. It is a miniature, dormant plant with tiny leaves (cotyledons or plumule), a tiny stem (hypocotyl), and a tiny root (radicle). When conditions are right, the embryo wakes up and starts growing.
- Endosperm – This is the lunchbox. It is a tissue that stores food (starch, proteins, oils) for the embryo to use when it germinates. In some seeds, the endosperm is consumed by the embryo before the seed matures, and the food is stored directly in the cotyledons instead.
- Seed Coat – This is the coat. It is a tough, protective outer layer that shields the embryo from injury, drying out, and disease. It often has a tiny scar called the hilum where the seed was attached to the mother plant, and a small pore called the micropyle that lets water enter during germination.
The micropyle is a tiny opening in the seed coat. It is not just a scar — it is a functional pore. Water enters through the micropyle to trigger germination, and later, the radicle (the first root) emerges through it.
Why This Matters for Exams
In NCERT textbooks (Class 11 Biology, Chapter 5), seed structure is taught to help you understand how plants reproduce and how seeds are adapted for survival. The key distinction you must know is between two types of seeds based on where the food is stored:
- Albuminous seeds – The endosperm remains present and stores food. Example: castor, coconut, maize.
- Exalbuminous seeds – The endosperm is completely used up during development, and food is stored in the cotyledons. Example: pea, bean, groundnut.
In exalbuminous seeds, the cotyledons become thick and fleshy because they have absorbed the endosperm. In albuminous seeds, the cotyledons remain thin and papery because the endosperm does the job of food storage.
A Simple Way to Visualise
Imagine a packed lunch in a lunchbox inside a backpack. The embryo is the child, the endosperm is the lunch, and the seed coat is the backpack. In an albuminous seed, the lunchbox is still full when the child opens it. In an exalbuminous seed, the child has already eaten the lunch and packed the food into its own pockets (the cotyledons) before the journey begins.
Common Exam Terms at a Glance
| Term | Meaning |
|---|---|
| Radicle | The part of the embryo that becomes the root |
| Plumule | The part that becomes the shoot (stem and leaves) |
In the monocot (grass-family) embryo, the radicle is enclosed by its own protective sheath, distinct from the sheath covering the plumule. …
Coleorrhiza is a protective sheath enclosing the radicle in grass-family (monocot) seeds, allowing the root to emerge safely on germination.
In the embryo of grass family (monocotyledonous) seeds such as maize:
- The embryo has a large and terminally-positioned scutellum (single cotyledon) on one side.
- The radicle (embryonic root) and root cap are enclosed in a sheath called the coleorrhiza.
- Similarly, the plumule (embryonic shoot) is enclosed by a sheath called the coleoptile. …
Showing the 12 most recent of 26 on this concept.
- CBSE 2026Set A1 markMCQQ.In which of the following seeds is perisperm not found?(a) Beet(b) Black pepper(c) Wheat(d) Both (A) and (B)
›Reveal solutionSolution
Wheat has no perisperm; beet and black pepper are examples of seeds where perisperm persists.
Perisperm is the residual, persistent nucellus that remains in the mature seed of a few plants. In seeds such as beet (Beta) and black pepper, the nucellus is not fully used up and remains as perisperm. In wheat, the nucellus is co …
- CBSE 2026Set A1 markMCQQ.What is cotyledon called in grass family?(a) Plumule(b) Radicle(c) Hypocotyl(d) Scutellum
›Reveal solutionSolution
In the grass family (Poaceae), the cotyledon is a shield-shaped structure called the scutellum.
Grasses are monocots and have a single cotyledon. In their embryo this cotyledon is highly modified into a shield-shaped structure that lies against the endosperm and absorbs food from it during germination — this is called the scutellum. The plumule is the embryoni …
- CBSE 2026Set BOTANY1 markMCQQ.In a developing monocot embryo, _____ is often called the scutellum.(a) plumule(b) cotyledon(c) radicle(d) root cap
›Reveal solutionSolution
In a developing monocot (e.g. grass family) embryo, the single cotyledon is specialised into a shield-shaped structure called the scutellum, which absorbs nutrients from the endosperm.
A mature dicot embryo has two cotyledons, a plumule (embryonic shoot) and a radicle (embryonic root). A mature monocot embryo, in contrast, has only a single cotyledon. In grasses (Poaceae) such as maize, rice and wheat, this single cotyledon is large, shield-shaped, and pressed against the endosperm; it is given the special name scutellum. The scutellum's main function is absorptive - during seed germination it secretes enzymes (like amylases, under gibberellin control) that digest the stored starch of the endosperm and absorb the resulting nutrients to nourish the growing embryo. The embryonal axis o …
- CBSE 2026Set ANNUAL1 markMCQQ.In a grass family, the cotyledon is called(a) plumule(b) radicle(c) embryo(d) scutellum
›Reveal solutionSolution
The scutellum is the specialised, shield-shaped single cotyledon characteristic of grass-family (monocot) embryos.
In the embryo of members of the grass family (Poaceae), the single cotyledon is highly modified into a shield-shaped structure known as the scutellum, situated laterally, one side pressed against the endosperm. It functions to absorb and transfer nutrients from the endosperm to the growing embryo axis during germination. The plumule (a) an …
- CBSE 2025Set 57/4/11 markMCQQ.Select the statements that are true for a typical dicotyledonous embryo from the given options.(i) It consists of an embryonal axis and scutellum.(ii) The portion of embryonal axis above the level of cotyledon is epicotyl.(iii) The portion of embryonal axis below the level of cotyledon is coleorhiza.(iv) The lower end of the embryo has radicle covered with a root cap. Choose the correct answer : (A)(i) and(ii) (B)(i) and(iii) (C)(iii) and(iv) (D)(ii) and (iv)
›Reveal solutionSolution
A dicot embryo has an epicotyl above the cotyledons and a radicle (with root cap) below; scutellum and coleorhiza are monocot features.
The structure of a seed embryo differs fundamentally between monocots and dicots, and recognizing these differences is essential for understanding seed anatomy. The question asks us to identify features specific to a dicotyledonous embryo, so we need to carefully distinguish what belongs to dicots versus what is characteristic of monocots.
Every angiosperm embryo, whether monocot or dicot, consists of an embryonal axis and one or more cotyledons (seed leaves). The embryonal axis is the young stem-root axis of the plant, and it has two distinct regions defined by their position relative to the cotyledons.
Let's examine each statement:
Statement (i): "It consists of an embryonal axis and scutellum."
The scutellum is the single, shield-shaped cotyledon found in monocots like maize and wheat. Dicots, by definition, have two cotyledons, not a scutellum. This statement is incorrect for dicots.
Statement (ii): "The portion of embryonal axis above the level of cotyledon is epicotyl."
This is accurate. The epicotyl is the part of the embryonal axis that lies above the point of attachment of the cotyledons. In dicots, the epicotyl terminates in the plumule, which is the embryonic shoot tip that will develop into the shoot system. This statement is correct.
NoteThe epicotyl often bears a few immature leaves in the embryo, visible as the plumule. After germination, this region grows into the stem and leaves above the cotyledons.
Statement (iii): "The portion of embryonal axis below the level of cotyledon is coleorhiza."
The coleorhiza is a protective sheath that covers the radicle in monocot embryos, particularly in grasses. In dicots, the portion of the embryonal axis below the cotyledons is simply called the hypocotyl, and it terminates in the radicle (the embryonic root). There is no coleorhiza in dicots. This statement is incorrect. …
- CBSE 2025Set 57/6/11 markMCQQ.Select the statements that are true for the seed of angiosperm from the given options :(i) Non-albuminous seeds have no residual endosperm.(ii) Residual, persistent nucellus in wheat is known as perisperm.(iii) Integuments of ovules harden as tough protective seed coat.(iv) Metabolic activity of the embryo slows down in dormancy. Choose the correct option : (A)(i) and(ii) (B)(ii) and(iii) (C)(iii) and(iv) (D)(i) and (iv)
›Reveal solutionSolution
In angiosperm seeds, the integuments harden into a protective seed coat, and the embryo’s metabolic activity slows during dormancy — but non-albuminous seeds lack endosperm, not residual endosperm, and the persistent nucellus in wheat is called perisperm only in certain other seeds like black pepper.
Let’s walk through each statement carefully, because the terminology around seed structure can be tricky — and the NCERT textbook is very precise about it.
Statement (i): “Non-albuminous seeds have no residual endosperm.”
This sounds plausible, but it’s not quite right. Non-albuminous seeds (also called exalbuminous seeds) are those in which the endosperm is completely consumed during embryo development, so the mature seed lacks endosperm altogether. The phrase “residual endosperm” would imply that some endosperm remains — but in non-albuminous seeds, there is none left. The NCERT clearly states that in such seeds (e.g., pea, groundnut), the endosperm is absent. So saying “no residual endosperm” is technically correct in meaning, but the wording is misleading because “residual” suggests something that could remain but doesn’t. More importantly, the NCERT uses the term “non-albuminous” precisely for seeds without endosperm — not for seeds that have some leftover. So this statement is false as phrased.
NoteA common confusion: “non-albuminous” means endosperm is absent at maturity. “Albuminous” seeds retain endosperm. The word “residual” is not used by NCERT for this distinction.
Statement (ii): “Residual, persistent nucellus in wheat is known as perisperm.”
This is incorrect. In wheat, which is a cereal grain, the persistent nucellus does not form a perisperm. The NCERT textbook specifically mentions that perisperm is the persistent nucellus found in seeds like black pepper and beet — not in wheat. In wheat, the endosperm is the major storage tissue, and the nucellus degenerates. So this statement is false.
Statement (iii): “Integuments of ovules harden as tough protective seed coat.” …
- CBSE 2025Set ANNUAL1 markQ.Fill in the blank: A typical dicotyledonous embryo consists of an ___ and two cotyledons.
›Reveal solutionSolution
A typical dicot embryo has an embryonal axis and two cotyledons attached to it.
In a dicotyledonous seed (e.g., gram, pea), the mature embryo consists of an embryonal axis bearing a radicle (embryonic root) at one end and a plumule (embryonic shoot) at the other, with two cotyledons attached laterally to the axis. The cotyledon …
- CBSE 2025Set ANNUAL1 markQ.Which among the following is a non-albuminous seed ? (Wheat, Groundnut, Maize, Barley)
›Reveal solutionSolution
Seeds in which the endosperm is used up completely during embryo development, so that the mature seed stores food in the cotyledons instead, are called non-albuminous seeds; among wheat, groundnut, maize and barley, only groundnut is non-albuminous.
Based on whether endosperm persists in the mature seed:
- Albuminous (endospermic) seeds: retain a part of the endosperm as the food-storing tissue at maturity, because it is not fully used up by the growing embryo — e.g. wheat, maize, barley (all cereals/monocots), castor. …
- CBSE 2024Set 57/3/11 markMCQQ.The part of the ovule that develops into protective coats of a seed after fertilization in a typical flowering plant is : (A) embryo sac (B) nucellus (C) integuments (D) megaspore
›Reveal solutionSolution
The integuments of the ovule develop into the protective seed coats after fertilization in a typical flowering plant.
In a flowering plant, the ovule is the structure within the ovary that contains the female gametophyte. Before fertilization, the ovule consists of several distinct parts: the nucellus (the central mass of tissue), the embryo sac (the female gametophyte inside the nucellus), and the integuments (the protective layers that surround the nucellus, leaving a small opening called the micropyle).
After fertilization, the entire ovule transforms into a seed. The zygote develops into the embryo, and the endosperm forms from the triploid nucleus. But what happens to the outer coverings? The integuments, which were already present as protective layers around the ovule, undergo a dramatic change. They become thick, hard, and often differentiated into two layers: the outer testa and the inner tegmen. Together, these form the seed coat, which protects the embryo and endosperm from mechanical injury, desiccation, and pathogens.
NoteIn some seeds, the nucellus may persist as a thin layer called the perisperm (e.g., in black pepper and beetroot), but it does not form the main protective coat. The embryo sac degenerates after fertilization, and the megaspore is the cell that gives rise to the embryo sac, not the seed coat. …
- CBSE 2024Set E1 markMCQQ.Scutellum present in the seeds of grass is called(a) Endosperm(b) Cotyledon(c) Seed coat(d) Embryonal axis
›Reveal solutionSolution
The scutellum is the single cotyledon of a grass (cereal) seed.
Grasses are monocots and their seeds have a single cotyledon. This cotyledon is modified into a shield-shaped structure lying against the endosperm, called the scutellum. It secretes enzymes and absorbs the digested food from the endosperm to nourish the growing embryo during g …
- CBSE 2024Set D1 markMCQQ.Persistent nucellus in the seed is known as:(a) Hilum(b) Tegmen(c) Chalaza(d) Perisperm
›Reveal solutionSolution
When the nucellus is not fully consumed during seed development and persists in the mature seed, this residual nucellar tissue is called the perisperm.
During seed development, the nucellus (the tissue surrounding the embryo sac within the ovule) is normally completely used up as the embryo and endosperm grow, providing nutrition to the developing seed.
However, in certain seeds, such as black pepper and beet, some part of the nucellus is not fully consumed and remains in the mature seed as a nutritive tissue. This persistent remnant of the nucellus is specifically termed the perisperm.
…
- CBSE 2024Set ANNUAL1 markMCQQ.An example of a non-albuminous seed is(a) Wheat(b) Maize(c) Pea(d) Castor
›Reveal solutionSolution
Seeds are classed as albuminous (retain endosperm) or non-albuminous (endosperm used up); pea belongs to the non-albuminous group.
During seed development, the endosperm nourishes the growing embryo. In some seeds (e.g., wheat, maize, castor) the endosperm persists in the mature seed and is used during germination — these are called albuminous (endospermic) seeds. In other seeds, such as pea, gram and groundnut, the endosperm is completely consumed by the developing embryo itself before the seed matures, so the mature seed has no resid …
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