Morphology of Plants MCQ Quiz - Objective Question with Answer for Morphology of Plants - Download Free PDF

The correct answer is Pea

Explanation:

• 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.

The correct answer is A-II, B-III, C-IV, D-I 

Explanation:

• 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.

Fig: L.S. of an embryo of grass

The correct answer is Aleurone layer

Explanation:

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.

Incorrect Options:

• Coleoptile: This is a protective sheath that covers the emerging shoot or plumule of monocot seeds during germination.
• Coleorhiza: The coleorhiza is a protective covering that encloses the emerging radicle (root) in monocot seeds.
• Integument: The integument is the protective outer layer of the ovule that eventually develops into the seed coat.

The correct answer is Statement I is incorrect but Statement II is correct

Explanation:

• 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.
  • ​​\(\overline{G}\): Represents an inferior ovary (the ovary is below other floral parts).
  • \(\underline{G}\): Represents a superior ovary (the ovary is above other floral parts).

Therefore, Statement I is incorrect but Statement II is correct

The correct answer is i - D, ii - C, iii - A, iv - B

Explanation:

The floral formula is a way to represent the structure of a flower using specific symbols. This formula includes information on the number of parts, symmetries, and fusion of different floral parts.

Brassicaceae (Cruciferae)

• Symmetry: Actinomorphic (radially symmetrical)
• Sepals (K): 4, free (or slightly united at the base)
• Petals (C): 4, arranged in a cross shape
• Stamens (A): 6 (tetradynamous: 4 long + 2 short)
• Carpels (G): 2, united (syncarpous)
• Floral Formula: 

Fabaceae (Leguminosae)

• Symmetry: Zygomorphic (bilaterally symmetrical)
• Sepals (K): 5, usually united (forming a calyx tube)
• Petals (C): 5 (papilionaceous: standard, wings, keel)
• Stamens (A): 10 (9 united + 1 free, or all 10 united)
• Carpels (G): 1, superior ovary
• Floral Formula: % K₍₅₎ C_1+2+(2) A_{(9)+1 or (10)} G₁

Liliaceae

• Symmetry: Actinomorphic
• Sepals (K): 3 and Petals (C): 3 (often similar in appearance, collectively referred to as 6 tepals)
• Stamens (A): 6
• Carpels (G): 3, united (syncarpous)
• Floral Formula: 

Solanaceae

• Symmetry: Actinomorphic
• Sepals (K): 5, united
• Petals (C): 5, united, often forming a tube
• Stamens (A): 5
• Carpels (G): 2, united (syncarpous)
• Floral Formula:

Concept: 

• Fruit refers to a mature or ripened ovary, developed after fertilization.
• The fruit consists of a wall or pericarp and seeds.
• When the pericarp is thick and fleshy, it is differentiated into the outer epicarp, the middle mesocarp, and the inner endocarp. 

Explanation:

• Fruit is said to be false fruit when the fruit is formed from the other parts of the flower as well as the ovary like the receptacle (base), the perianth, thalamus, inflorescence, or calyx.

• Examples of such fruits are strawberries, pineapple, mulberry, apples, pears, etc.

• The given figure is of a false fruit.

• False fruit develops from other floral parts and the thalamus along with the development of the ovary wall.

• Therefore, the correct answer is option 4.

Additional Information If the fruit is formed without fertilization of the ovary, it is called a parthenocarpic fruit.

Concept: 

• When a flower can be divided into two similar halves only in one particular vertical plane, it is called zygomorphic symmetry.
• When a flower can be divided into two equal radial halves in any radial plane passing through the center, it is said to be actinomorphic symmetry. 
• Asymmetry means dividing any object into two parts that are not equally divided. 

​

Explanation:

Option 1: Datura and chilly show actinomorphic flowers. zygomorphic: Cassia.

Option 2: Mustard show actinomorphic flowers. zygomorphic: Gulmohar, and Cassia.

Option 3: Zygomorphic for e.g. Pea, Gulmohar, bean, Cassia.

Option 4: Datura and chilly show actinomorphic flowers. 

So, the correct answer is Option 3.

Concept:

• Stem helps in providing structure and support to the plant, as well as helps in conduction. But sometimes stems get modified to perform functions other than conduction & support
• Some of the types of stem modification include
• Underground Stem Modification - In plants like ginger and potato, the stem stores large amounts of food and remains under the soil.
• Sub-Aerial Modification - In grass and pumpkin, the stem lies horizontally and helps in vegetative propagation.
• Aerial-Stem Modification - Auxiliary buds get transformed into tendril for protection in plants like Pea, Rose. Phylloclade in xerophytes like Opuntia.

Explanation

• Phylloclade is the aerial modification of stem, having several nodes and internodes and is modified into a flat, fleshy, and green leaf-like structure and carries out photosynthesis like a leaf and also stores food.
• It is seen in Opuntia.

Additional Information

The correct answer is lamina.Key Points

• The broad green part of the leaf is known as lamina, which is also referred to as the leaf blade.
• The lamina is the main part of the leaf that is responsible for photosynthesis, as it contains the chlorophyll pigment.

Additional Information

• The petiole is the stalk that attaches the leaf blade to the stem of the plant.
• Veins are the small tubes that run through the leaf blade, transporting water and nutrients to the cells.
• The midrib is the central vein that runs down the center of the leaf blade, providing support and structure to the leaf.

Concept:

• Stamens are the male reproductive organs of flowering plants.
• Stamens consist of an anther, the site of pollen development, and in most species a stalk-like filament, which transmits water and nutrients to the anther.

• Stamens in a flower may either remain free (polyandrous) or may be united in varying degrees.
• When the stamens are united into one bunch or one bundle are called monadelphous, and when united into two bundles are called diadelphous.

​Explanation: 

•  In china rose, the stamens are united into one bunch or one bundle (monadelphous).
• In Citrus the stamens are united into more than two bundles (polyadelphous). 
• In peas, the stamen are united into two bundles (diadelphous).

​

Therefore, the correct answer is option 4, Pea.

The correct answer is Neither 1 nor 2.

Key Points

• The two parts of a typical stamen are the long and slender stalk called the filament and the terminal generally bilobed structure called the anther. Hence statements 1 and 2 are not correct.
• The proximal end of the filament is attached to the thalamus or the petal of the flower.
• The number and length of stamens are variable in flowers of different species.
• If you collect a stamen each from ten flowers (each from different species), you would be able to appreciate the large variation in size seen in nature.
• Careful observation of each stamen under a dissecting microscope and making neat diagrams would elucidate the range in shape and attachment of anthers in different flowers.
• A typical angiosperm anther is bilobed with each lobe having two thecae, i.e. they are dithecous.
• Often a longitudinal groove runs lengthwise separating the theca.
• The bilobed nature of an anther is very distinct in the transverse section of the anther.
• The anther is a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe.
• The microsporangia develop further and become pollen sacs.
• They extend longitudinally all through the length of an anther and are packed with pollen grains.

Concept: 

• Stems are modified to perform different functions. 
• Some stems perform the function of storage of food, support, protection and vegetative propagation.
• For example, Underground stems of potato, ginger, turmeric, zaminkand, Colocasia are modified to store food in them. 

Explanation:

Statement a:  The leaflets are modified into pointed hard thorns in Citrus and Bougainvillea. This statement is incorrect as axillary buds of stems get modified into woody, straight and pointed thorns. Thorns are found in many plants such as Citrus and Bougainvillea. . They protect plants from browsing animals.  

Statement b: Axillary buds form slender and spirally coiled tendrils in cucumber and pumpkin. This statement is correct.

Statement c: Stem is flattened and fleshy in Opuntia and modified to perform the function of leaves. This statement is correct.

Statement d: Rhizophora shows vertically upward growing roots that help to get oxygen for respiration. This statement is correct.

Statement e: Subaerially growing stems in grasses and strawberries help in vegetative propagation.  This statement is correct.

Only option 4 comprises all correct statements. Therefore, option 4 is the correct answer.

The correct answer is pistil.Key Points

• The pistil is the female reproductive part of a flower, consisting of three parts: the stigma, style, and ovary.
• The stigma is the sticky top of the pistil that collects pollen.
• The style is a tube-like structure that connects the stigma to the ovary.
• The ovary contains the ovules, which develop into seeds after fertilization.

Additional Information

• The anther and filament are parts of the male reproductive system in flowers, collectively called the stamen.
• Filament is the slender stalk that holds the anther in the flower's male portion.
• The part of the stamen called the anther is where pollen is made.
• The pollen is carried to the pistil for fertilization by insects or wind.

Concept:

• There are two types of leaves Simple leaf & Compound leaf
• Simple leaf: A leaf is said to be simple, when its lamina is entire or when incised, the incisions do not touch the midrib.
• Compound leaf: When the incisions of the lamina reach up to the midrib breaking it into a number of leaflets, the leaf is called a compound leaf.
• The compound leaves may be of two types Pinnately compound leaf & Palmately compound leaf

​Explanation:

The correct option is ''Palmately compound leaf''

• In palmately compound leaves, the leaflets are attached at a common point, i.e. at the tip of the petiole, as in silk cotton.

​

      Silk Cotton Leaf

Important Points  

• Leaf and leaflets can be differentiated as:
• A bud is present in the axil of the petiole in both simple and compound leaves, but not in the axil of leaflets of the compound leaf.

Additional Information

• Pinnately Compound leaf: In a pinnately compound leaf, a number of leaflets are present on a common axis, the rachis, which represents the midrib of the leaf as in neem.

                      Leaf of Neem

Concept:

• The flower is the reproductive unit in the angiosperms. It is meant for sexual reproduction.
• A typical flower has four different kinds of whorls arranged successively on the swollen end of the stalk or pedicel, called the thalamus or receptacle.
• These are calyx, corolla, androecium and gynoecium. Calyx and corolla are accessory organs, while androecium and gynoecium are reproductive organs.

Explanation:

• Based on the position of calyx, corolla and androecium in respect of the ovary on the thalamus, the flowers are described as hypogynous, perigynous and epigynous.

Hypogynous flower:

• In the hypogynous flower, the gynoecium occupies the highest position while the other parts are situated below it. The ovary in such flowers is said to be superior, e.g., mustard, china rose and brinjal.

Thereby, the hypogynous flower has a superior ovary seated on the thalamus

Position of floral parts on thalamus : (a) Hypogynous, (b) and (c) Perigynous, (d) Epigynous

Additional Information

• Perigynous flower: If gynoecium is situated in the centre and other parts of the flower are located on the rim of the thalamus almost at the same level, it is called perigynous. The ovary here is said to be half inferior, e.g., plum rose, peach.
• Epigynous flower: In epigynous flowers, the margin of the thalamus grows upward enclosing the ovary completely and getting fused with it, the other parts of the flower arise above the ovary. Hence, the ovary is said to be inferior as in flowers of guava and cucumber, and the ray florets of sunflower.