NEET Biology Morphology of Flowering Plants MCQs Set 13

Answer: (a) Fusiform root

Explanation:
1. Radish is a modified tap root that is swollen in the middle and tapers at both ends.
2. That spindle shape is called fusiform.

Teacher's Note:
1. Fusiform: radish. Conical: carrot. Napiform: turnip and beetroot.

Answer: (c) Nodulated roots

Explanation:
1. Root nodules of legumes such as pea, gram and bean house Rhizobium bacteria.
2. Roots bearing such nodules are called nodulated roots.

Teacher's Note:
1. Nodulated roots are a storage-free modification, useful for nitrogen fixation. Link them with the family Fabaceae.

Answer: (b) Modified tap root

Explanation:
1. Turnip develops from the radicle, so it is a tap root.
2. The tap root becomes swollen and almost round, which is the napiform type.

Teacher's Note:
1. Turnip, sugar beet and beetroot are napiform tap roots. Sweet potato, by contrast, is an adventitious root.

Answer: (d) Stilt root

Explanation:
1. Napiform, fusiform and tuberous roots all store reserve food.
2. Stilt roots arise from the lower nodes of the stem (as in sugarcane and maize) and only support the plant.

Teacher's Note:
1. Stilt roots and prop roots are for support, not storage. Remember storage roots: fusiform, conical, napiform, tuberous, nodulated is for nitrogen fixation.

Answer: (a) Plumule

Explanation:
1. In the embryo the plumule is the future shoot and the radicle is the future root.
2. So the stem and leaves of the plant arise from the plumule.

Teacher's Note:
1. Plumule gives the shoot; radicle gives the primary root. Endosperm is only stored food.

Answer: (b) Eichhornia

Explanation:
1. An offset is a short, thick lateral branch of an aquatic plant that gives rise to a new plant, as in water hyacinth (Eichhornia) and Pistia.
2. Cynodon has a runner, Fragaria a stolon and Mentha a sucker.

Teacher's Note:
1. Offset: aquatic plants (Eichhornia, Pistia). Sucker: Mentha, banana, chrysanthemum. Runner: grass. Stolon: strawberry, jasmine.

Answer: (a) Defensive organs

Explanation:
1. Thorns (modified stems, as in Citrus and Bougainvillea) and spines (modified leaves, as in Opuntia) protect the plant from browsing animals.
2. They play no role in respiration or storage.

Teacher's Note:
1. Thorn = modified axillary bud/stem. Spine = modified leaf or stipule.

Answer: (b) Grass

Explanation:
1. Parallel venation is a feature of monocot leaves, and grass is a monocot.
2. Castor, gram and mustard are dicots with reticulate venation.

Teacher's Note:
1. Monocots: parallel venation, fibrous roots, trimerous flowers. Dicots: reticulate venation, tap roots.

Answer: (c) Phylloclade

Explanation:
1. In a phylloclade the stem becomes flat and green and does photosynthesis, while the leaves are reduced to spines to cut water loss.
2. This is seen in Opuntia.

Teacher's Note:
1. Phylloclade: flattened or cylindrical green stem of xerophytes. Cladode: a phylloclade of only one or two internodes.

Answer: (c) Providing support to the big tree

Explanation:
1. Prop roots hang from the horizontal branches of the banyan and grow into the soil as pillars.
2. Their function is mechanical support for the heavy crown.

Teacher's Note:
1. Respiration is done by pneumatophores (Rhizophora), not prop roots. Prop roots are adventitious.

Answer: (c) Pitcher of Nepenthes

Explanation:
1. The pitcher of Nepenthes is a modified leaf that traps insects.
2. Rhizome, corm and tuber are all underground stems.

Teacher's Note:
1. Leaf modifications: pitcher, tendrils of pea, spines, phyllode. Stem modifications: thorn, tendril of grape, tuber, rhizome.

Answer: (a) Phyllode

Explanation:
1. In Australian Acacia the petiole becomes flat and green and acts as a leaf blade, called a phyllode.
2. Phylloclade and cladode are modified stems and corm is an underground stem.

Teacher's Note:
1. Phyllode is a petiole; phylloclade and cladode are stems.

Answer: (d) Scorpioid cyme

Explanation:
1. In a scorpioid cyme the flowers appear alternately on the right and left of the axis, which gives a zig-zag arrangement (as in Heliotropium and Solanum).
2. Helicoid cyme is one-sided and coiled, while cyathium and capitulum are special inflorescences.

Teacher's Note:
1. Remember: helicoid is a one-sided coil; scorpioid is a zig-zag.

Answer: (b) Thalamus

Explanation:
1. The thalamus (receptacle) is the swollen tip of the pedicel on which sepals, petals, stamens and carpels are borne.
2. All four whorls arise from it.

Teacher's Note:
1. Thalamus = receptacle. Pedicel is the stalk below it.

Answer: (b) Cladode

Explanation:
1. Ruscus has a cladode, a green flattened branch of limited growth (about two internodes) that does photosynthesis.
2. Asparagus has a one-internode cladode.

Teacher's Note:
1. Cladode = short phylloclade (Asparagus: 1 internode, Ruscus: 2 internodes).

Answer: (a) Monoadelphous

Explanation:
1. Stamens united by their filaments into one bundle are monoadelphous, as in China rose.
2. Two bundles is diadelphous and many bundles is polyadelphous.

Teacher's Note:
1. Mono = 1 bundle (China rose), di = 2 (pea), poly = many (lemon).

Answer: (a) Flowers

Explanation:
1. Flowers are borne only by angiosperms, the flowering plants.
2. Roots, stems and seeds also occur in gymnosperms.

Teacher's Note:
1. Flower is the reproductive organ unique to angiosperms.

Answer: (a) Union of dissimilar parts

Explanation:
1. Adhesion means union of different whorls, such as stamens with petals (epipetalous).
2. Union of similar parts is cohesion.

Teacher's Note:
1. Adhesion = unlike parts; cohesion = like parts.

Answer: (c) Papilionaceous

Explanation:
1. The corolla of pea has five petals arranged as standard, wings and keel, resembling a butterfly.
2. This is the papilionaceous corolla.

Teacher's Note:
1. Campanulate is bell-shaped and rotate is wheel-shaped.

Answer: (c) Carpel(s)

Explanation:
1. The whorls from outside are calyx (sepals), corolla (petals), androecium (stamens) and gynoecium (carpels).
2. The fourth whorl is the gynoecium.

Teacher's Note:
1. Order: calyx, corolla, androecium, gynoecium.

Answer: (a) Cruciferae

Explanation:
1. Siliqua is a long, dry fruit with a false septum (replum), typical of mustard and radish.
2. Its short form is called a silicula.

Teacher's Note:
1. Cruciferae: siliqua fruit, parietal placentation, tetradynamous stamens.

Answer: (a) Berry

Explanation:
1. Brinjal fruit has a fleshy pericarp throughout and many seeds.
2. That is a berry.

Teacher's Note:
1. Berry: tomato, brinjal, banana, guava, grape.