201. Match each seed condition with the corresponding fate of endosperm. Each Column II entry is used once.
| Column I | Column II |
|---|
| P. Albuminous seed | 1. Endosperm largely consumed during embryo development |
| Q. Non-albuminous seed | 2. Endosperm persists in the mature seed |
| R. Developing embryo | 3. May use endosperm as a nutritional source |
| S. Mature retained endosperm | 4. Characteristic basis of albuminous condition |
ⓐ. P-1, Q-2, R-4, S-3
ⓑ. P-3, Q-4, R-2, S-1
ⓒ. P-2, Q-1, R-3, S-4
ⓓ. P-4, Q-3, R-1, S-2
Correct Answer: P-2, Q-1, R-3, S-4
Explanation: Seed classification depends partly on what happens to endosperm during development. In albuminous seeds, a substantial amount of endosperm persists into the mature seed, so P maps to retained endosperm. In non-albuminous seeds, endosperm is largely consumed as the embryo develops, giving Q the opposite fate. The developing embryo can use endosperm as a nutrient source, which explains why its presence may diminish during embryogenesis. Persistent mature endosperm is the defining developmental basis of the albuminous condition. The mapping links seed category to developmental history rather than treating albuminous and non-albuminous as arbitrary labels. What matters is whether endosperm remains detectable as a storage tissue at maturity or has already been substantially used during embryo development.
202. Consider the following statements about endosperm fate in mature seeds.
I. Albuminous seeds retain endosperm at maturity.
II. Non-albuminous seeds have generally consumed the endosperm during embryo development.
III. Endosperm persistence and endosperm formation are identical concepts.
IV. A seed may have formed endosperm earlier even if little or none remains at maturity.
ⓐ. I and III only
ⓑ. II and III only
ⓒ. I, II and IV only
ⓓ. I, II, III and IV
Correct Answer: I, II and IV only
Explanation: Albuminous and non-albuminous describe the fate of endosperm by seed maturity, not whether endosperm ever formed after fertilisation. Albuminous seeds retain a noticeable endosperm reserve, while in non-albuminous seeds the developing embryo has used most or all of that tissue. Statement IV captures the important developmental implication: a mature seed can lack persistent endosperm even though endosperm formed normally earlier and served a nutritional role. Statement III incorrectly treats persistence and origin as the same event. Formation begins with the primary endosperm cell after triple fusion, whereas persistence is determined by how much of that tissue remains after embryonic development. The biological contrast prevents mature seed anatomy from being misread as direct evidence that endosperm formation never occurred.
203. Mature seeds from four plants are examined.
| Seed | Endosperm formed after fertilisation | Endosperm remaining at maturity |
|---|
| P | Yes | Abundant |
| Q | Yes | Almost none |
| R | No | Abundant |
| S | No | Almost none |
Under the normal sexual pathway, which record best represents a non-albuminous seed?
ⓐ. Q
ⓑ. P
ⓒ. R
ⓓ. S
Correct Answer: Q
Explanation: A non-albuminous seed does not imply failure of endosperm formation. Endosperm normally develops after triple fusion and supports the growing embryo, but in a non-albuminous seed it is largely consumed during embryo development and little remains at maturity. Record Q captures both parts of that history: endosperm formed after fertilisation, yet almost none persists in the mature seed. Record P instead represents the retained-endosperm condition characteristic of albuminous seeds. The records in which no endosperm formed do not represent the normal sexual pathway specified by the stated conditions. The table separates developmental origin from mature persistence. Classification is based on the final fate of endosperm, while the earlier post-fertilisation pathway can still have proceeded normally.
204. Arrange the following stages of typical dicot embryogeny in developmental order.
P. Heart-shaped embryo
Q. Proembryo
R. Mature embryo
S. Globular embryo
ⓐ. Q → S → P → R
ⓑ. P → S → Q → R
ⓒ. Q → P → S → R
ⓓ. S → Q → R → P
Correct Answer: Q → S → P → R
Explanation: After the zygote begins embryonic development, the early dicot embryo passes through a recognisable sequence of forms. The proembryo represents an early multicellular stage. Continued division and organisation produce the globular stage. As the two cotyledonary regions begin to become evident, the embryo acquires the characteristic heart-shaped appearance. Further differentiation then produces the mature embryo with two cotyledons and an organised embryonal axis. The sequence is Q followed by S, P and R. This developmental order should be understood as progressive differentiation rather than as independent labels. The heart-shaped stage follows the globular stage as the developing cotyledons alter the outline of the embryo, whereas the mature form represents later completion of the major embryonic structures. The proembryo is the earliest listed multicellular stage, the globular form follows, and cotyledon initiation produces the characteristic heart-shaped stage before the mature embryo is established. Morphological differentiation increases along this sequence.
205. Use the arrangement described below. A newly formed zygote lies at the micropylar end of the embryo sac. Nearby endosperm development has already begun before the zygote enters extensive division. Which interpretation best fits this arrangement?
ⓐ. The zygote is positioned at the chalazal end and develops before endosperm
ⓑ. Endosperm originates from the zygote at the micropylar end
ⓒ. The primary endosperm cell occupies the egg position and later develops into the embryo
ⓓ. The micropylar zygote begins substantial embryogeny after early endosperm development
Correct Answer: The micropylar zygote begins substantial embryogeny after early endosperm development
Explanation: Syngamy occurs in the egg of the micropylar egg apparatus, so the newly formed zygote is located at the micropylar end of the embryo sac. Meanwhile, triple fusion establishes the primary endosperm cell in the central region, and endosperm development normally begins before the zygote undergoes substantial embryonic growth. The described arrangement combines position with timing. The zygote does not produce endosperm; the two lineages arise from different fusion products. Likewise, the primary endosperm cell does not replace the egg or generate the embryo. Correct interpretation requires preserving both spatial organisation and developmental identity: micropylar zygote for the embryonic lineage, central-cell endosperm lineage for nutritional support. Endosperm development normally begins before substantial embryo development, providing a nutritive tissue for the young embryo as growth proceeds. Chromosome-set arithmetic follows fusion history: two haploid sets form the zygote, while three haploid contributions establish the usual triploid endosperm nucleus.
206. A fertilised ovule forms a normal zygote, but establishment of endosperm is greatly delayed. The zygote remains at the micropylar end and later begins to divide. Which prediction is most biologically justified?
ⓐ. Embryo growth may be compromised by delayed nutritional support
ⓑ. The zygote must immediately transform into endosperm
ⓒ. The embryo will necessarily become triploid
ⓓ. The ovule will automatically become a fruit without seed formation
Correct Answer: Embryo growth may be compromised by delayed nutritional support
Explanation: Early endosperm formation normally precedes substantial embryo development and provides nutritional support for the growing embryo. If the zygote forms normally but endosperm establishment is greatly delayed, the embryonic lineage is present but the usual timing relationship with its nutritive tissue is disturbed. The best-supported prediction is that coordination between embryo growth and nutrition may be compromised. The evidence does not justify changing the zygote into endosperm or altering its ploidy; those identities were established by distinct fertilisation events. Likewise, an ovule does not simply become a fruit. The ovary forms the fruit while the ovule forms the seed. The changed condition specifically affects the developmental partnership between embryo and endosperm rather than reassigning their origins.
207. Consider the following statements about early dicot embryogeny.
I. The zygote occurs at the micropylar end of the embryo sac.
II. The proembryo precedes the globular stage.
III. The heart-shaped stage follows the globular stage.
IV. The mature embryo normally appears before formation of the proembryo.
ⓐ. The true statements are I and IV only
ⓑ. The true statements are II and IV only
ⓒ. The true statements are I, II and III only
ⓓ. The true statements are I, II, III and IV
Correct Answer: The true statements are I, II and III only
Explanation: The zygote forms from the egg, which lies at the micropylar end of the embryo sac, establishing the location given in statement I. Once embryonic division proceeds, the early dicot developmental sequence progresses through the proembryo, globular stage and heart-shaped stage before reaching the mature embryo. Statements II and III correctly preserve that progression. Statement IV reverses the sequence by placing the mature structure before an early embryonic stage. The developmental pattern represents increasing organisation: early cell divisions establish the proembryo, continued growth produces a globular form, emergence of cotyledonary regions generates the heart-shaped outline, and later differentiation produces the mature embryo. Recognising these stage relationships is more useful than memorising the names separately as each later stage depends on structures established earlier.
208. Match each part of a typical dicot embryo with its correct positional or structural description. Each Column II entry is used once.
| Column I | Column II |
|---|
| P. Epicotyl | 1. Portion of embryonal axis below cotyledons |
| Q. Hypocotyl | 2. Terminal root region with root cap |
| R. Plumule | 3. Portion of embryonal axis above cotyledons |
| S. Radicle | 4. Embryonic shoot at the upper end |
ⓐ. P-1, Q-3, R-2, S-4
ⓑ. P-4, Q-2, R-3, S-1
ⓒ. P-3, Q-4, R-1, S-2
ⓓ. P-3, Q-1, R-4, S-2
Correct Answer: P-3, Q-1, R-4, S-2
Explanation: A typical dicot embryo contains two cotyledons attached to an embryonal axis. The axis above the level of cotyledon attachment is the epicotyl, and its upper end terminates in the plumule, which represents the embryonic shoot. The portion below the cotyledons is the hypocotyl, and its lower end terminates in the radicle, which bears the root cap. The mapping follows a continuous upper-to-lower orientation rather than four independent definitions. Position on the embryonal axis identifies epicotyl and hypocotyl, while the structures at their terminal ends identify plumule and radicle. This spatial framework is especially useful when interpreting a labelled or verbally described embryo since cotyledon position serves as the central reference point for distinguishing the upper and lower regions.
209. A dicot embryo is oriented with two cotyledons attached at the middle of its embryonal axis. Region P lies above their point of attachment and ends in a small embryonic shoot. Region Q lies below them and ends in an embryonic root with a root cap. P and Q are respectively:
ⓐ. epicotyl and hypocotyl
ⓑ. hypocotyl and epicotyl
ⓒ. plumule and radicle
ⓓ. radicle and plumule
Correct Answer: epicotyl and hypocotyl
Explanation: The level at which the cotyledons attach divides the dicot embryonal axis into two principal regions. The portion above this level is the epicotyl, which terminates in the plumule or embryonic shoot. The portion below the cotyledons is the hypocotyl, which continues toward the radicle or embryonic root. The supplied description gives both positional and terminal clues, so Region P is identified as the epicotyl and Region Q as the hypocotyl. Plumule and radicle are not the entire upper and lower axis regions; they are structures located at their ends. Using cotyledon attachment as a fixed reference prevents confusion among these four closely related terms and allows the internal organisation of a dicot embryo to be reconstructed without an external diagram.
210. Four labelled regions of a dicot embryo are summarised below.
| Region | Position or feature |
|---|
| P | Axis above cotyledon level |
| Q | Embryonic shoot at the upper end |
| R | Axis below cotyledon level |
| S | Embryonic root with root cap |
Which sequence correctly identifies P, Q, R and S?
ⓐ. Hypocotyl, radicle, epicotyl, plumule
ⓑ. Plumule, epicotyl, radicle, hypocotyl
ⓒ. Epicotyl, radicle, hypocotyl, plumule
ⓓ. Epicotyl, plumule, hypocotyl, radicle
Correct Answer: Epicotyl, plumule, hypocotyl, radicle
Explanation: The cotyledon level provides the central landmark for interpreting the embryonal axis. Region P lies above that level and is the epicotyl. At its upper end, Region Q is the embryonic shoot or plumule. Region R lies below the cotyledon attachment and is the hypocotyl, while Region S is the terminal embryonic root or radicle, which carries the root cap. The correct sequence preserves the anatomical continuity from upper axis to lower axis. A common confusion is to treat plumule and epicotyl, or radicle and hypocotyl, as interchangeable. They are related but not identical: epicotyl and hypocotyl are axis regions, whereas plumule and radicle are terminal embryonic structures associated with those regions. Reading the axis from the cotyledon level fixes the labels: epicotyl lies above and ends in the plumule, whereas hypocotyl lies below and ends in the radicle. The table encodes one continuous positional sequence rather than four unrelated structures.
211. A young dicot embryo has two normal cotyledons and a normal hypocotyl-radicle region, but the portion of its embryonal axis above the cotyledons fails to differentiate properly. The structure most directly associated with that defective region is the:
ⓐ. root cap at the radicle tip
ⓑ. plumule at the upper embryonic end
ⓒ. lower hypocotyl region
ⓓ. seed coat derived from integuments
Correct Answer: plumule at the upper embryonic end
Explanation: In a typical dicot embryo, the embryonal axis is divided relative to the cotyledon level. The portion above the cotyledons is the epicotyl and terminates in the plumule, while the portion below is the hypocotyl and terminates in the radicle. A defect specifically affecting the upper axis would be expected to involve the epicotyl-plumule region rather than the lower hypocotyl-radicle region. The cotyledons themselves are stated to be normal, and the seed coat is a maternal structure derived from integuments rather than part of the embryonal axis. The positional description is the primary guide: upper axis corresponds to epicotyl and plumule, while lower axis corresponds to hypocotyl and radicle. A typical dicot embryo carries two cotyledons on an embryonal axis whose epicotyl ends in the plumule and whose hypocotyl ends in the radicle.
212. A monocot embryo is described with one shield-shaped cotyledon lateral to the embryonal axis. The shoot apex is enclosed by Structure P, while the radicle and root cap are enclosed by Structure Q. The cotyledon, P and Q are respectively:
ⓐ. coleoptile, scutellum and coleorrhiza
ⓑ. scutellum, coleoptile and coleorrhiza
ⓒ. scutellum, coleorrhiza and coleoptile
ⓓ. plumule, coleoptile and scutellum
Correct Answer: scutellum, coleoptile and coleorrhiza
Explanation: A typical monocot embryo has a single cotyledon called the scutellum, situated toward one side of the embryonal axis. The upper region of the axis bears the shoot apex and leaf primordia, which are enclosed by a protective sheath called the coleoptile. At the lower end, the radicle and its root cap are enclosed within another protective sheath, the coleorrhiza. The three structures have distinct identities and positions: scutellum is the cotyledon, coleoptile protects the embryonic shoot region, and coleorrhiza encloses the embryonic root region. Recognising this upper-lower orientation is important: the two sheaths are often confused despite protecting opposite ends of the monocot embryonal axis. Dicot and monocot embryos share shoot and root poles even though they differ in cotyledon number and in the specialised sheaths described for the monocot embryo.
213. Match each monocot embryonic structure with its correct description. Each Column II entry is used once.
| Column I | Column II |
|---|
| P. Scutellum | 1. Sheath surrounding the radicle and root cap |
| Q. Coleoptile | 2. Single cotyledon |
| R. Coleorrhiza | 3. Embryonic root region |
| S. Radicle | 4. Sheath surrounding the shoot apex and leaf primordia |
ⓐ. P-2, Q-4, R-1, S-3
ⓑ. P-4, Q-2, R-3, S-1
ⓒ. P-2, Q-1, R-4, S-3
ⓓ. P-3, Q-4, R-1, S-2
Correct Answer: P-2, Q-4, R-1, S-3
Explanation: The scutellum is the single cotyledon of the monocot embryo, so P maps to the second description. The coleoptile is the sheath that encloses the shoot apex and young leaf primordia, placing it around the upper embryonic region. The coleorrhiza performs the corresponding protective role at the lower end by enclosing the radicle and root cap. The radicle itself is the embryonic root. The mapping distinguishes a cotyledon, two protective sheaths and the root structure enclosed by one of those sheaths. Coleoptile and coleorrhiza should not be treated as interchangeable names: their similarity is functional protection, but their targets are different and occur at opposite ends of the embryonal axis.
214. A monocot embryo forms a normal scutellum and coleorrhiza, but its coleoptile fails to develop. Which structure is most directly left without its normal embryonic sheath?
ⓐ. Radicle and root cap
ⓑ. Single cotyledon
ⓒ. Seed coat with the persistent micropyle
ⓓ. Shoot apex and leaf primordia
Correct Answer: Shoot apex and leaf primordia
Explanation: The coleoptile is specifically associated with the upper part of the monocot embryonal axis. It encloses and protects the shoot apex together with the young leaf primordia. A failure of coleoptile development most directly affects protection of this embryonic shoot region. The radicle and root cap are enclosed separately by the coleorrhiza, which is stated to be normal. The scutellum is the single cotyledon rather than a shoot-protective sheath, while the seed coat and micropyle are seed structures derived from ovular tissues and are not formed by the coleoptile. The changed condition isolates one component of monocot embryo architecture and shows that the two embryonic sheaths have complementary but non-overlapping positional roles. A monocot embryo has one cotyledon called the scutellum, together with a coleoptile around the shoot region and a coleorrhiza around the root region.
215. Consider the following statements about a typical monocot embryo.
I. Its single cotyledon is called the scutellum.
II. The coleoptile encloses the shoot apex and leaf primordia.
III. The coleorrhiza encloses the radicle and root cap.
IV. The scutellum is a hardened ovular integument forming the seed coat.
ⓐ. The true statements are I and IV only
ⓑ. The true statements are I, II and III only
ⓒ. The true statements are II and IV only
ⓓ. The true statements are I, II, III and IV
Correct Answer: The true statements are I, II and III only
Explanation: Statements I, II and III describe the normal organisation of a monocot embryo. The scutellum is the single cotyledon, the coleoptile protects the upper shoot region, and the coleorrhiza surrounds the radicle and its root cap at the lower end. Statement IV confuses an embryonic structure with a maternal seed covering. Seed coats develop from the integuments of the ovule, whereas the scutellum belongs to the embryo produced from the zygote. The structural distinction is important: seed structure contains tissues of different developmental origins. The monocot embryo itself includes the scutellum and embryonal axis with its protected shoot and root regions, while the surrounding seed coat originates outside the embryonic lineage.
216. Dicot and monocot embryos are compared below.
| Feature | Embryo P | Embryo Q |
|---|
| Cotyledons | Two | One scutellum |
| Shoot region | Plumule exposed within embryo organisation | Shoot apex enclosed by coleoptile |
| Root region | Radicle with root cap | Radicle and root cap enclosed by coleorrhiza |
Which interpretation is best supported?
ⓐ. P is monocot and Q is dicot because Q has protective sheaths
ⓑ. P and Q are both monocots because both possess a radicle
ⓒ. P is dicot; Q is monocot with specialised embryonic sheaths
ⓓ. P and Q differ only in seed-coat structure
Correct Answer: P is dicot; Q is monocot with specialised embryonic sheaths
Explanation: Embryo P has two cotyledons, which identifies the typical dicot pattern. Embryo Q has one cotyledon called the scutellum and additionally shows the coleoptile and coleorrhiza, structures characteristic of the monocot embryo described here. Both embryos possess an embryonal axis and root and shoot regions, so the presence of a radicle alone cannot distinguish the two groups. The important comparison combines cotyledon number with the specialised protective sheaths surrounding the monocot shoot and root regions. The table demonstrates both a shared embryonic plan and a structural difference. Dicot and monocot embryos are not simply distinguished by seed coats; the decisive features here belong to the embryo itself. Coleoptile and coleorrhiza are both protective sheaths, but they act at opposite poles of the monocot embryonal axis and cannot substitute for one another.
217. A mature seed is opened without damaging its contents. A protective outer covering surrounds an embryo with cotyledonary tissue and an embryonal axis, while a small pore remains in the covering at a position corresponding to an opening once present in the ovule. The pore is the:
ⓐ. chalazal region of the seed coat
ⓑ. persistent micropylar opening
ⓒ. funicular attachment scar
ⓓ. persistent nucellar remnant
Correct Answer: persistent micropylar opening
Explanation: During seed formation, the fertilised ovule matures into a seed and its integuments harden to form the protective seed coat or coats. The micropyle, however, does not disappear completely. It persists as a small pore in the mature seed coat. Since the pore is traced back to an opening that was already present between the integuments of the ovule, the structure is identified as the persistent micropyle. The chalaza is the opposite ovular region, the funicle is the attachment stalk, and nucellus is internal ovular tissue. This developmental continuity becomes functionally important later: the micropyle can provide a route for water and oxygen to enter when a viable seed encounters suitable conditions for germination.
218. Fertilisation and embryonic development proceed normally, but the ovular integuments remain soft and fail to harden during seed maturation. Which consequence is most directly expected?
ⓐ. The embryo will necessarily become triploid
ⓑ. The mature seed will have defective seed coats
ⓒ. The endosperm will convert into pericarp
ⓓ. The persistent micropyle will become the radicle
Correct Answer: The mature seed will have defective seed coats
Explanation: The integuments of the ovule are the developmental precursors of the seed coat or coats. Their hardening during seed maturation creates an important protective covering around the embryo and storage tissues. If the integuments remain soft and fail to mature normally, the direct defect is inadequate seed-coat formation and reduced physical protection of the seed contents. This change does not alter the ploidy of the embryo, which was established by syngamy, nor does it change endosperm into the ovary-derived pericarp. The micropyle is an opening retained in the seed coat, not a precursor of the radicle. The biological relation links maternal ovular tissue with its later structural function in the mature seed. The ovular integuments give rise to seed coats, whereas the ovary wall gives rise to the pericarp, so these coverings have different structural origins.
219. Developmental tracing of a normal seed and its associated tissues gives four origins. Which set is entirely correct?
ⓐ. Seed coat — integuments; embryo — zygote; endosperm — nucellus; persistent perisperm — primary endosperm cell
ⓑ. Seed coat — ovary wall; embryo — zygote; endosperm — primary endosperm cell; persistent perisperm — nucellus
ⓒ. Seed coat — integuments; embryo — primary endosperm cell; endosperm — zygote; persistent perisperm — nucellus
ⓓ. Seed coat — integuments; embryo — zygote; endosperm — primary endosperm cell; persistent perisperm — nucellus
Correct Answer: Seed coat — integuments; embryo — zygote; endosperm — primary endosperm cell; persistent perisperm — nucellus
Explanation: Seed development brings together tissues with different developmental origins. The protective seed coat forms from the ovular integuments, so it is maternal sporophytic tissue. The embryo develops from the zygote produced by syngamy and represents the new sporophyte. Endosperm develops from the primary endosperm cell established after triple fusion and provides nutritional support during seed development. Perisperm, when present, is persistent residual nucellus and is also maternal in origin. The four-way relation is useful as these tissues can coexist within one mature seed while belonging to different developmental lineages. Identifying them by origin prevents the common error of treating every seed component as a direct product of the zygote or of double fertilisation.
220. A mature seed has a hardened outer coat traced to the ovular integuments, a small persistent pore in that coat and an embryo containing an embryonal axis with cotyledonary tissue. Which developmental interpretation fits all three observations?
ⓐ. The seed coat is zygotic, the pore is newly formed after fertilisation and the embryo is maternal nucellus
ⓑ. The coat and embryo both arise from the ovary wall, while the pore is a ruptured stigma
ⓒ. The seed coat comes from integuments, the pore is the persistent micropyle, and the embryo is zygotic
ⓓ. The coat is endospermic tissue, the pore is the hilum and the embryo develops from the pericarp
Correct Answer: The seed coat comes from integuments, the pore is the persistent micropyle, and the embryo is zygotic
Explanation: During normal seed formation, the fertilised ovule matures into the seed while several of its structures retain distinct developmental identities. The integuments harden to form the protective seed coats, and the opening that was present between the integuments at the ovular stage commonly persists as the micropyle. The embryo develops from the zygote and contains the embryonal axis together with cotyledonary structures appropriate to the embryo type. These origins show why a mature seed is not developmentally uniform. Its protective coat is maternal sporophytic tissue, its persistent pore reflects earlier ovular architecture, and its embryo belongs to the new sporophytic generation established by syngamy. Tracing each feature back to the ovule or zygote resolves all three observations in one developmental interpretation.
