31 Years NEET Previous Year Questions: Morphology of Flowering - 1 Free

• Flowers can be classified based on their symmetry into two main types: actinomorphic and zygomorphic flowers.
• Actinomorphic flowers: These flowers are radially symmetrical, meaning they can be divided into equal halves along multiple planes. Examples include mustard, chilli, and datura.
• Zygomorphic flowers: These flowers are bilaterally symmetrical, meaning they can only be divided into equal halves along one particular plane. Examples include pea, gulmohar, cassia and bean.
• A flower is asymmetric (irregular) if it cannot be divided into two similar halves by any vertical plane passing through the centre, as in canna.

• A floral formula is a symbolic representation of the structure of a flower using specific symbols and abbreviations to denote its various characteristics.
• It provides information about the symmetry of the flower, the number and arrangement of floral organs, and the position of the ovary.

Key symbols used in a floral formula include:

• ⊕: Represents actinomorphic (radially symmetrical) flowers.
• %: Represents zygomorphic (bilaterally symmetrical) flowers.
• G : Represents an inferior ovary (the ovary is below other floral parts).
• G: Represents a superior ovary (the ovary is above other floral parts).

Therefore, Statement I is incorrect but Statement II is correct

Aleurone layer:

• The aleurone layer is a single layer of specialized cells found at the interface of the endosperm and the seed coat.
• The outer covering of the endosperm separates the embryo by a proteinous layer called the aleurone layer.
• It is rich in proteins and plays a crucial role during seed germination by secreting enzymes such as amylase and protease.
• These enzymes break down starch and proteins stored in the endosperm into simpler compounds, which are then utilized by the growing embryo.
• The aleurone layer also contributes to the seed's nutritional value in cereal grains.

• (A) Scutellum: The scutellum is a specialized cotyledon found in monocot seeds, such as those of grasses. It is part of the monocotyledonous embryo and assists in the absorption of nutrients from the endosperm during seed germination.
• (B) Non-albuminous seeds: Non-endospermous seeds (also known as non-albuminous seeds) do not contain endosperm at maturity because it is absorbed by the developing embryo. Non- albuminous seeds have no residual endosperm as it is completely consumed during embryo development. Examples include groundnut,bean, gram, and pea seeds.
• (C) Epiblast: Epiblast refers to a structure in some monocot seeds, such as grasses. It is a rudimentary or vestigial structure. The epiblast in seeds is typically a small, scale-like outgrowth that does not develop into a significant part of the plant but may assist in some way during germination or early seedling development
• (D) Persiperm: In some seeds such as black pepper and beet, remnants of nucellus are also persistent. This residual, persistent nucellus is the perisperm.
  

• A is incorrect because in cymose inflorescence, the flowers are borne in a basipetal (from the bottom upwards) rather than acropetal (from the top down) succession.
• B is incorrect because the flowers of gulmohar are zygomorphic (bilaterally symmetrical) and not actinomorphic (radially symmetrical).
• C is correct as described in the cucumber flowers, where the thalamus grows upward and fuses with the ovary.
• D is correct as bracts are modified or reduced leaves found at the base of the pedicel (flower stalk).
• E is correct as mustard flowers are hypogynous, meaning the ovary is at the base, and other parts (sepals, petals, stamens) are above it.

Thus, the correct answer is (D). C, D, E only.

• A. Polyadelphous refers to the condition where the filaments of stamens are united into more than two bundles. This corresponds to I.
• B. Syncarpous refers to the condition where the carpels are fused. This corresponds to IV.
• C. Staminode refers to a sterile stamen, which is a stamen that does not produce pollen. This corresponds to II.
• D. Epipetalous refers to the condition where the stamens are attached to the petals. This corresponds to III.

Therefore, the correct answer is (A). A-I, B-IV, C-II, D-III.

• A. Vexillary aestivation refers to the arrangement of petals in a flower, where the largest petal (standard) overlaps the two lateral petals (wings), which in turn overlap the smallest petal (keel). This arrangement is found in Pea (III).
• B. Epipetalous stamens means that the stamens are attached to the petals. This is characteristic of Brinjal (I).
• C. Epiphyllous stamens refers to stamens attached to the leaves. This arrangement is found in Lily (IV).
• D. Perigynous flower refers to a flower where the ovary is placed at the centre, and the other floral parts (petals, sepals, and stamens) are attached to the rim of the ovary. This is seen in Peach (II).

Thus, the correct answer is (A). A- III, B-I, C-IV, D-II.

• A. China rose: The ovary in China rose is axile (I), meaning the ovules are attached to the central column (axis) of the ovary, with chambers formed by the partition.
• B. Mustard: The ovary in mustard is parietal (IV), meaning the ovules are attached to the walls of the ovary.
• C. Primrose: The ovary in primrose is free central (I), meaning the ovules are attached to a central column without partition.
• D. Marigold: The ovary in marigold is basal (II), meaning the ovary is positioned at the base of the flower, and the ovules are attached to the base.

Thus, the correct answer is (C). A- III, B-IV, C-I, D-II.

The correct answer is: Option A: A-IV, B-II, C-I, D-III
Monoadelphous: Stamens united into a single bundle by their filaments. Example: China rose
Diadelphous: Stamens united into two bundles by their filaments. Example: Pea
Polyadelphous: Stamens united into more than two bundles by their filaments. Example: Citrus
Epiphyllous: Stamens arise from the perianth (sepals and petals) rather than from the receptacle. Example: Lily

The radicle is the part of the seed that will develop into the root when the seed germinates.
In the provided diagram, 'C' represents the radicle.
Topic in NCERT: Structure of a Dicotyledonous Seed
Line in NCERT: "The embryo is made up of a radicle, an embryonal axis and one (as in wheat, maize) or two cotyledons (as in gram and pea)."

Rose has a half-inferior ovary, thus it is a Perigynous flower.
Pea: The placenta forms a ridge along the ventral suture of the ovary, and ovules are borne on this ridge forming two rows.
Cotton: Twisted aestivation is present.
Mango: The fruit is a drupe.

An actinomorphic flower is one that can be divided into two equal halves along any plane passing through its center. This is also known as radial symmetry.
Datura flowers exhibit radial symmetry, as their petals are arranged in a circular pattern around the center.

The other options are incorrect:

• Cassia: Zygomorphic (bilateral symmetry)
• Pisum: Zygomorphic (bilateral symmetry)
• Sesbania: Zygomorphic (bilateral symmetry)