NCERT Exemplar: Morphology of Flowering Plants

MULTIPLE CHOICE QUESTIONS

Q.1. Rearrange the following zones choose the correct option as seen in the root in vertical section and choose the correct option.
(A) Root hair zone
(B) Zone of meristems
(C) Root cap zone
(D) Zone of Maturation
(E) Zone of elongation
Option:
(a) C, B, E, A, D
(b) A, B, C, D, E
(c) D, E, A, C, B
(d) E, D, C, B, A
Ans. (a)
Solution.
(C) Root cap zone
(B) Zone of meristems
(E) Zone of elongation
(A) Root hair zone
(D) Zone of maturation

Q.2. In an inflorescence where flowers are borne laterally in an acropetal succession, the position of the youngest floral bud shall be
(a) Proximal 
(b) Distal 
(c) Intercalary 
(d) Anywhere
Ans. (b)
Solution.
In racemose type of inflorescences the main axis continues to grow, the flowers are borne laterally in an acropetal succession, i.e. youngest flower is present at apex and oldest flower is present at the base. In racemose, inflorescence the growth of floral axis is unlimited or indefinite.
In cymose type of inflorescence the main axis terminates in a flower, hence is limited in growth. The flowers are borne in a basipetal. order, i.e. youngest flower is present at the base and oldest flower is present at the apex. In cymose inflorescence oldest flower remains in center and youngest towards the periphery. This type of arrangement is called centrifugal.

Q.3. The mature seeds of plants such as gram and peas, possess no endosperm, because
(a) These plants are not angiosperms
(b) There is no double fertilization in them
(c) Endosperm is not formed in them
(d) Endosperm gets used up by the developing embryo during seed development.
Ans. (d)
Solution.
The mature seeds of plants such as gram and peas, possess no endosperm, because endosperm gets used up by the developing embryo during seed development.

Q.4. Roots developed from parts of the plant other than radicle are called
(a) Tap roots 
(b) Fibrous roots
(c) Adventitious roots 
(d) Nodular roots
Ans. (c)
Solution.
Roots developed from parts of the plant other than radicle are called adventitious roots.

Q.5. Venation is a term used to describe the pattern of arrangement of
(a) Floral organs 
(b) Flowers in inflorescence
(c) Veins and veinlets in a lamina 
(d) All of them
Ans. (c)
Solution.
Venation is a term used to describe the pattern of arrangement of veins and veinlets in a lamina.

Q.6. Endosperm, a product of double fertilization in angiosperms is absent in the seeds of
(a) Coconut 
(b) Orchids 
(c) Maize 
(d) Castor
Ans. (b)
Solution.
Endosperm, a product of double fertilization in angiosperms is absent in the seeds of orchids.

Q.7. Many pulses of daily use belong to one of the families below (tick the correct answer).
(a) Solanaceae 
(b) Fabaceae 
(c) Liliaceae 
(d) Poaceae
Ans. (b)
Solution.
Many pulses of daily use belong to one of the family fabaceae.
Solanaceae (potato family)
Liliaceae (lily family)
Poaceae (cereal or grass family).

Q.8. The placenta is attached to the developing seed near the
(a) Testa 
(b) Hilum 
(c) Micropyle 
(d) Chalaza
Ans. (b)
Solution.
The placenta is attached to the developing seed near the hilum.

Q.9. Which of the following plants is used to extract the blue dye?
(a) Trifolium 
(b) Indigofera 
(c) Lupin 
(d) Cassia
Ans. (b)
Solution.
Blue dye is obtained from Indigofera tinctoria which belongs to family fabaceae.

Q.10. Match the followings and choose the correct option.

Options:
(a) A-i, B-ii, C-iii, D-iv 
(b) A-ii, B-i, C-iv, D-iii 
(c) A-iv, B-ii, C-i, D-iii 
(d) A-ii, B-iv, C-i, D-iii
Ans. (b)
Solution.

VERY SHORT ANSWER TYPE QUESTIONS

Q.1. Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of O₂, root growth is restricted or completely stopped. How do the plants growing in marshlands or swamps obtain their O₂ required for root respiration?
Ans. In some plants such as Rhizophora and Sonneratia (mangrove plant) growing in swampy areas near river mouths (saline marshy soil or halophytes), many roots come out of the ground and grow vertically upwards (negatively geotropic: against gravitational force). Such roots, called pneumatophores or breathing roots or respiratory roots, help to get oxygen for respiration.

Q.2.Write floral formula for a flower which, is bisexual; actinomorphic; pentamerous sepal, petal, stamens free with ovary, syncarpous, superior, trilocular with axile placentation.
Ans. 

Q.3. In Opuntia the stem is modified into a flattened green structure to perform the function of leaves (i.e., photosynthesis). Cite two other examples of modifications of plant parts for the purpose of photosynthesis.
Ans. Some plants of arid regions modify their stems into flattened (Opuntia), or fleshy cylindrical (Euphorbia) structures. These modified stems of indefinite growth are called phylloclades or cladodes. They contain chlorophyll and carry out photosynthesis.

Q.4. In swampy areas like the Sunderbans in West Bengal, plants bear special kind of roots called __________ .
Ans. Pneumatophores

Q.5. In aquatic plants like Pistia and Eichhornia, leaves and roots are found near _____________.
Ans. Node

Q.6. Reticulate and parallel venation are characteristic of ________ and ______ respectively.
Ans. Dicotyledons and monocotyledons

Q.7. In epigynous flower, ovary is situated below the _______.
Ans. Calyx, corolla and androecium.

Q.8. Add the missing floral organs of the given floral formula of Fabaceae.

Ans.

Q.9. Name the body part modified for food storage in the following
(a) Carrot __________________________
(b) Colocasia __________________________
(c) Sweet potato __________________________
(d) Asparagus __________________________
(e) Radish __________________________
(f) Potato __________________________
(g) Dahlia __________________________
(h) Turmeric __________________________
(i) Gladiolus __________________________
(j) Ginger __________________________
(k) Portulaca __________________________
Ans. 
(a) Carrot - Tap root
(b) Colocasia - Stem (corm)
(c) Sweet potato - Root
(d) Asparagus - Root
(e) Radish - Root
(f) Potato - Stem (tuber)
(g) Dahlia - Adventitious root (tuberous roots)
(h) Turmeric - Stem (rhizome)
(i) Gladiolus - Stem (corm)
(J) Ginger - Stem (rhizome)
(k) Portulaca - Adventitious root

SHORT ANSWER TYPE QUESTIONS

Q.1. Give two examples of roots that develop from different parts of the angiospermic plant other than the radicle.
Ans. The root that arise from parts of plant other than radicle are called adventitious roots.
Examples:
- Pneumatophores - for respiration (e.g., Rhizophora)
- Stilt roots or prop roots - for support (e.g., Banyan, maize brace roots)

Q.2. The essential functions of roots are anchorage and absorption of water and minerals in the terrestrial plant. What functions are associated with the roots of aquatic plants. How are roots of aquatic plants and terrestrial plants different?
Ans. The roots of aquatic plants help mainly in anchorage and balance rather than extensive absorption; they may be reduced or modified. Terrestrial roots absorb water and minerals and provide strong anchorage. Differences include:

• Aquatic plant roots are often reduced, floating or clasping; terrestrial roots are well developed and branched.
• Aquatic roots may lack root hairs; terrestrial roots have root-hair zones for absorption.

Q.3. Draw diagrams of a typical monocot and dicot leaves to show their venation pattern.
Ans.

Q.4. A typical angiosperm flower consists of four floral parts. Give the names of the floral parts and their arrangements sequentially.
Ans. A typical flower has four different kinds of whorls arranged successively on the swollen end of the stalk or pedicel, called thalamus or receptacle. These are:

• Calyx - outermost whorl; members are sepals.
• Corolla - second whorl; members are petals.
• Androecium - third whorl; composed of stamens (male reproductive organs).
• Gynoecium - innermost whorl; composed of one or more carpels (female reproductive organs).

Q.5. Given below are floral formulae of some plants. Draw floral diagrams from these formulae.

Ans.

Q.6. Reticulate venation is found in dicot leaves while in monocot leaves venation is of parallel type. Mention one exception to this generalization .
Ans. Smilax and Dioscorea are monocots having reticulate venation. Calophyllum and Eryngium are dicots having parallel venation.

Q.7. You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a 'pitcher'? How does this modification help the plant for food even though it can photosynthesize like any other green plant?
Ans. In Nepenthes, the lamina (leaf blade) is modified into a pitcher. These plants usually grow in nitrogen-poor soils. The pitcher traps insects and digests them to absorb nitrogenous compounds and other minerals, supplementing their nutrition while leaves perform photosynthesis.

Q.8. Mango and coconut are 'drupe' type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?
Ans. The edible part of coconut is the endosperm (seed). The milk of tender coconut represents free-nuclear liquid endosperm - the watery nutritive tissue present in the cavity of the developing seed.

Q.9. How can you differentiate between free central and axile placentation?
Ans. Free central placentation: ovules are borne on a central axis and septa are absent (e.g., Dianthus, Primrose). Axile placentation: ovules are attached to a central axis in a multilocular ovary formed by fused carpels (e.g., China rose, tomato, lemon).

Q.10. Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils.
(a) Cucumber
(b) Peas
(c) Pumpkins
(d) Grapevine
(e) Watermelons
Ans. 
(a) Cucumber - stem tendrils
(b) Peas - leaf tendrils
(c) Pumpkins - stem tendrils
(d) Grapevine - stem tendrils
(e) Watermelons - stem tendrils

Q.11. Why is maize grain usually called as a fruit and not a seed?
Ans.  Maize is an example of caryopsis - a simple, one-seeded dry indehiscent fruit in which pericarp and testa are fused. Because a fruit wall (pericarp) is present and fused with the seed coat, maize grain is botanically a fruit (caryopsis) and not just a seed.

Q.12. Tendrils of grapevines are homologous to the tendril of pumpkins but are analogous to that of pea. Justify the above statement.
Ans. Tendrils of grapevines and pumpkins are both derived from stem (stem tendrils); hence they are homologous (same origin). Tendrils of grapevines and peas perform the same function (support) but have different origins (grapevine: stem; pea: leaf), so they are analogous (different origin, similar function).

Q.13. Rhizome of ginger is like the roots of other plants that grows underground. Despite this fact ginger is a stem and not a root. Justify.
Ans.  A rhizome is an underground stem growing horizontally. Ginger is a stem because it has nodes, internodes and scale leaves and bears axillary buds - features of stems, not roots.

Q.14. Differentiate between.
(a) Bract and Bracteole
(b) Pulvinus and petiole
(c) Pedicel and peduncle
(d) Spike and spadix
(e) Stamen and staminode
(f) Pollen and pollenium
Ans.
(a) A reduced leaf found at the base of the pedicel is called a bract, while a small leaf-like structure present between bract and flower is called a bracteole.
(b) Pulvinus is a swollen leaf base (often movable) seen in some legumes; petiole is the stalk connecting lamina to the stem (mesopodium).
(c) Pedicel is the stalk of an individual flower; peduncle is the stalk of an inflorescence or a solitary flower.
(d) Spike - sessile flowers attached along an elongated axis (e.g., Achyranthes). Spadix - a specialised fleshy spike with a large bract called a spathe (e.g., Colocasia, banana inflorescence).
(e) Stamen is a fertile male organ; a sterile stamen is called a staminode.
(f) Pollen is the male gametophyte or microspore; a compact mass of pollens forming a unit is called a pollinium (found in Calotropis and many orchids).

LONG ANSWER TYPE QUESTIONS

Q.1. Distinguish between families Fabaceae, Solanaceae, Liliaceae on the basis of gynoecium characteristics (with figures). Also write economic importance of any one of the above family.
Ans. 

(a) Gynoecium - diagnostic characters
(i) Fabaceae - Usually monocarpellary or bicarpellary depending on subfamily; ovary often unilocular or seemingly marginal; placentation commonly marginal (in papilionaceous flowers) or variable.

(ii) Solanaceae - Usually bicarpellary, syncarpous; carpels often placed obliquely; ovary bilocular with axile placentation.

(iii) Liliaceae - Typically tricarpellary, syncarpous, ovary superior with axile placentation.

(b) Economic importance of Fabaceae:

• Source of pulses: gram (chickpea), arhar (pigeon pea), lentil, etc.
• Edible oils: soybean, groundnut (note: groundnut is actually in Fabaceae? Groundnut is Fabaceae - Arachis hypogaea).
• Dyes: Indigofera (indigo dye).
• Fibres: sunhemp (for ropes and textiles).
• Fodder and green manuring: Sesbania, Trifolium (clovers).
• Ornamentals: lupin.
• Medicinal plants: e.g., Glycyrrhiza glabra (liquorice).

Q.2. Describe various stem modifications associated with food storage, climbing and protection.
Ans. Stems show many modifications adapted to particular functions:
Storage:

• Tuber: Swollen underground stem storing starch - potato.
• Rhizome: Horizontal underground stem (ginger, turmeric) storing food and aiding perennation.
• Corm: Short, vertical, swollen underground stem with scale leaves (Colocasia, Gladiolus).
• Bulb: Short stem with fleshy scale leaves (onion, tulip).

Climbing:

• Tendrils: Modified axillary buds or stems that coil and support climbing (grapevine, cucumber).
• Twining stems: Entire stem twines around a support (Ipomoea).

Protection:

• Thorns: Modified stems that are hard and pointed, providing protection (Bougainvillea, Citrus).

Photosynthetic modification:

• Phylloclades / cladodes: Flattened or fleshy photosynthetic stems (Opuntia, Euphorbia).

Q.3. Stolon, offset and rhizome are different forms of stem modifications. How can these modified forms of stem be distinguished from each other?
Ans. Distinctions among these stems:

• Stolon (runner): An elongated, horizontal above-ground or near-ground stem with long internodes; it gives rise to new plants at nodes (strawberry runner).
• Offset: A short, lateral branch with short internodes forming a rosette and producing new plantlets (found in aquatic plants like Pistia, Eichhornia).
• Rhizome: Horizontal underground stem (e.g., ginger, turmeric, lotus) with nodes, scale leaves and axillary buds; aids vegetative propagation.

Q.4. The mode of arrangements of sepals or petals in a floral bud is known as aestivation. Draw the various types of aestivation possible for a typical pentamerous flower.
Ans. Aestivation describes how sepals or petals in a whorl are arranged in the floral bud. Major types are:

• Valvate: Margins just meet without overlapping (e.g., Calotropis).
• Twisted (contorted): Each petal/sepal overlaps the next in one direction (e.g., China rose, cotton).
• Imbricate: Overlapping occurs but not in a definite direction (e.g., Cassia, Gulmohar).
• Vexillary (papilionaceous): Specialized imbricate: the large standard petal overlaps two wing petals which overlap the two keel petals (fabaceous flowers like pea).

Q.5. The arrangements of ovules within the ovary is known as placentation. What does the term placenta refer to? Name and draw various types of placentations in the flower as seen in T.S. or V.S.
Ans. The placenta is the region or cushion of tissue inside the ovary where ovules are attached. Types of placentation include:

• Parietal: Ovules attached to inner wall of a unilocular ovary (e.g., × many cucurbits).
• Marginal: Ovules borne on the margin of a single carpel (typical of many legumes).
• Axile: Ovules attached to a central column in a multilocular ovary formed by fused carpels (e.g., tomato, China rose).
• Free central: Ovules on a central axis in an otherwise unilocular ovary (e.g., Dianthus).
• Basal: Single ovule attached at the base of the ovary (e.g., sunflower).

Q.6. Sunflower is not a flower. Explain.
Ans. Sunflower is an inflorescence called a capitulum or head. The flattened receptacle bears many small flowers (florets) and is surrounded by an involucre of bracts. Two types of florets are present:

• Ray florets: Zygomorphic, often female or sterile, with a strap-shaped corolla on the periphery.
• Disc florets: Actinomorphic, bisexual tubular florets in the centre.

Examples include members of the family Asteraceae (Compositae): Helianthus (sunflower), Tagetes (marigold), Dahlia.

Q.7. How do you distinguish between hypogeal germination and epigeal germination? What is the role of cotyledon (s) and the endosperm in the germination of seeds?
Ans.
Hypogeal germination: Epicotyl elongates first and plumule emerges while cotyledons remain below ground (e.g., many monocots such as maize, rice; some dicots like pea, gram).
Epigeal germination: Hypocotyl elongates first, lifting cotyledons above soil (e.g., sunflower, mustard, cucumber, bean).
The cotyledons act as storage organs and sometimes photosynthetic organs; the endosperm provides nutritive reserve (starch, proteins, oils). In some seeds (e.g., pea, gram) the endosperm is consumed during embryo development and mature seed appears without free endosperm.

Q.8. Seeds of some plants germinate immediately after shedding from the plants while in other plants they require a period of rest before germination. The later phenomena is called as dormancy. Give the reasons for seed dormancy and some methods to break it.
Ans. Seed dormancy is a period when viable seeds do not germinate even under favourable external conditions. Causes include:

• Hard impermeable seed coat preventing water/gas entry.
• Presence of chemical inhibitors (e.g., abscisic acid, phenolic compounds).
• Immature embryos.

Methods to break dormancy:

• Scarification: Mechanical or chemical weakening of hard seed coats.
• Stratification: Chilling (pre-cold treatment) of seeds to overcome physiological dormancy.
• Passage through animal digestive tract or microbial action in soil can naturally scarify seeds.
• Application of growth regulators like gibberellic acid (GA3), nitrates, or treatment with auxins/cytokinins in some cases.
• Changing environmental cues such as light or temperature cycles to suit species requirements.