Set-I: Past Entrance Papers

Hint

(a) Fabaceae was earlier called Papilionoideae. Flowers of Fabaceae are zygomorphic(%),
hermaphrodite, have 5 fused sepals \(\left(K_{(5)}\right)\), have 5 petals out of which 2 are fused \((1+2+(2))\) have 9 united stamens and 1 free stamen \((C 9)+1)\) and have 1 superior ovary \(\left(\underline{G}_{1}\right)\).

This way the floral formula is made and thus, similarly to Brassicaceae, Liliaceae, and Solanaceae.

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(d) The roots that originate from the base of the stem are fibrous roots. In a fibrous root system, the primary roots stop growing and become rudimentary, while new roots for anchorage and absorption develop from the base of the stem. This type of root formation is observed in monocot like a wheat plant.

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(d) Grass leaves are isobilateral or typical monocot leaves. In such leaves, at places, the upper or adaxial epidermis contains groups of larger, thin-walled, colourless cells called bulliform cells. These cells are highly vacuolated and can store water, if available. However, these cells lose water and become flaccid in case of water deficiency.

Hint

(a) Option (a) is correct. It can be explained as A flower, that has four different whorls arranged successively on the swollen end of the stalk or pedicel called thalamus or receptacle. In mustard, the flower is hypogynous, i.e., the gynoecium occupies the highest position while the other parts are situated below it. The ovary in such flowers is said to be superior.

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(d) Ray floret have inferior ovary. Ray floret is a condition in flower where any of a number of strap-shaped and typically sterile florets that form the ray e.g., Sunflower Epigynous flower are formed in the family Asteraceae.

Neuter flowers have undeveloped or nonfunctional sexual organs. They have pistils and stamens that are nonfunctional or absent. Ray florets of sunflower are neuter flowers; disc florets are bisexual, also in some more Asteraceae, e.g. Centaurea.

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(c) The ovary is half inferior in Plum. A half inferior ovary is embedded or surrounded by the receptacle. Such flowers are termed perigynous or half-epigynous. In some classifications, half-inferior ovaries are not recognized and are instead grouped with either the superior or inferior ovaries.

The apple is a pome (fleshy) fruit, in which the ripened ovary and surrounding tissue both become fleshy and edible. The apple flower of most varieties requires cross-pollination for fertilization.

Hint

(a) Both mango and coconut are drupe, belonging to the class of simple succulent fruits. These are also called stone fruit as the endocarp is stony and non-edible. These fruits develop from the monocarpellary ovary. In coconut, epicarp is membranous and mesocarp is fibrous. In mango, the mesocarp is fleshy and pulpy.

Thus, statements (i), (iii), (iv) are correct while (ii) is incorrect.

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(d) The attachment point of the funicle and body of ovule is known as the hilum. It is the point where the ovule attaches to the base. It is generally present as an eye of the seed as it is present as a scar.

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(c) Floral formula of Liliaceae is

It represents bracteate, actinomorphic, bisexual flowers having six tepals and six epitepalous stamens. The ovary is superior with a three-lobed stigma.

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(c) Alstonia shows whorled phyllotaxy. In a whorled phyllotaxy, more than two leaves arise at a node and form a whorl. Mustard and China rose show alternate phyllotaxy. Calotropis shows the opposite phyllotaxy.

Hint

(c) In parietal placentation the ovules develop on the inner wall of an ovary or in the peripheral part and the number of placentae corresponds to the number of carpels. It occurs in bicarpellary or multicarpellary but unilocular ovary, e.g. mustard, Argemone, etc.

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(d) Bicarpellary ovary with obliquely placed septum is seen in the members of the family Solanaceae. e.g. Solanum tuberosum.

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\(\begin{array}{lll}\text { (d) Basal } & : & \text { Sunflower } \\ \text { Axile } & : & \text { China rose } \\ \text { Parietal } & : & \text { Mustard } \\ \text { Free central } & : & \text { Dianthus }\end{array}\)
In flowering plants, placentation is the attachment of ovules inside the ovary. The ovules inside a flower’s ovary (which later become the seeds inside a fruit) are attached via funiculi, the plant part equivalent to an umbilical cord. The part of the ovary where the funiculus attaches is referred to as the placenta.

Hint

(a) Persistent nucellus in the seed is known as perisperm. The albuminous seeds usually retain a part of endosperm as it is not completely used up during embryo development. But in some seeds, remnants of nucellus are also persistent, e.g. black pepper and beet.

Hint

(a) Some lateral roots of mangroves become specialised as pneumatophores in saline mud flats. These are lateral roots that grow upward (negative geotropism) for varying distances and function as the site of oxygen intake for the submerged primary root system.

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(c) Winged pollen grains are present in Pinus. Each pollen grain has two wing-like structures which enables it to float in the air, as an adaptation for dispersal by the wind.

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(d) Coconut fruit is a fibrous drupe with a fibrous mesocarp.

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(b) Thorns are hard, pointed straight structures for protection against grazing animals. These are modified stems.

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(b) The edible part of the coconut is the endosperm. Coconut water is free nuclear endosperm and the white kernel is the cellular endosperm.

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(a) Halophytes growing in saline soils show vivipary for seed germination and have pneumatophores for gaseous exchange.

Psammophytes are plant that thrives in shifting sands, primarily in deserts. They are marked by a number of adaptations that enable them to exist on wind-blown sands. In such an environment, the plants are often covered with sand, or their root system is exposed.

Hint

(a) Phylloclades are flattened green stems which have taken over the function of photosynthesis while cladodes are only the branches of the stem that are modified to take over the function of leaves. Cladodes may not be flattened as in Ruscus aculeatus, cladodes are leaf-like with spiny tip whereas, in Asparagus, they are slightly flattened, fleshy, straight, or curved pointed structures which develop in clusters in the axil of scale leaves.

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(c) Pitcher of Nepenthes is a modification of leaf. In Nepenthes, the pitchers are meant for catching and digesting insects. The lamina is modified into pitcher. The leaf apex gives rise to a coloured lid for attracting insects.

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(c) Members of Liliaceae possess tricarpellary, syncarpous gynoecium with superior ovary. The ovary is trilocular with two to many ovules in each loculus.

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(b) Only Salvia, mustard, radish, and turnip have stamens of different length in their flowers. Hence, the correct answer is (b).

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(b) Polyadelphous condition represents the cohesion of stamens. In this condition stamens of a flower are fused by their filaments only to form many groups, e.g., Citrus.

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(a) Free central placentation is found in Dianthus. Parietal placentation is present in Argemone and Brassica whereas Citrus has axile placentation in the ovary.

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(a) The flowers of Brassica are radially symmetrical whereas the flowers of Trifolium, Pisum, and Cassia are zygomorphic.

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(b) The cotyledons are known as seed leaves, they are attached to the embryonic axis. Dicotyledons typically have two cotyledons and monocotyledons have only one cotyledon. The single shield-shaped cotyledon in grains is known as scutellum.

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(d) Coconut water is the clear liquid inside young green coconuts (fruits of the coconut palm). In early development, it serves as a suspension for the endosperm of the coconut during the nuclear phase of development. As growth continues, the endosperm matures into its cellular phase and deposits into the rind of the coconut meat.

Hint

(a) The seeds of monocotyledonous plants have only one cotyledon. In the family Poaceae (e.g., wheat, maize, etc.), this cotyledon is called scutellum, situated towards the lateral side of the embryonal axis. It provides nourishment to the developing embryo.

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(d) China rose, mustard, brinjal, potato, onion, and tulip are the plants that have superior ovary whereas, in guava and cucumber, the ovary is inferior.

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(d) Axile placentation occurs in syncarpous pistils. The ovary is partitioned into two or more chambers. Placentae occur in the central region where the septa meet so that an axile column bearing ovules is formed e.g., shoe flower (pentalocular), lemon (multilocular), etc.

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(d) Pistia (water lettuce) is a floating aquatic plant. In aquatic plants, roots are generally poorly developed and do not take part in the absorption of water. Water is absorbed by the general body surface in these plants.

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(a) The given floral formula is of Family Solanaceae. Among the given options, only Petunia belongs to Family Solanaceae. Allium is a member of Family Liliaceae, Sesbania is of Family Leguminosae and Brassica is a member of Family Brassicaceae or Cruciferae.

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(b) 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.

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(d) The flowers of Family Papilionaceae have butterfly-shaped corolla (papilionaceous corolla). The posterior or outermost petal is the largest and is called standard or vexillum, two lateral petals are similar and generally clawed, are called wings or alae and the two anterior petals called keel are fused enclosing stamens and carpels. This type of petal arrangement is found in beans, gram, pea, Indigofera, etc.

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(c) In xerophytic plants, the leaves modify into sharp, pointed spines e.g. Aloe, Solanum surattense, Opuntia, Asparagus, etc. This modification is either for the protection of plants or to lessen transpiration or for both.

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(a) Coconut water is the free nuclear endosperm which is used.

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(c) Parthenocarpic fruits (eg – banana) are produced without fertilization of ovule.

Parthenogenesis is a natural form of asexual reproduction in which growth and development of embryos occur without fertilization by sperm. In animals, parthenogenesis means the development of an embryo from an unfertilized egg cell. In plants, parthenogenesis is a component process of apomixis.

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(a) The flowers of cucumber are unisexual, which means they have only male flowers or only female flowers.

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(c) A true fruit consists of a pericarp (fruit wall) formed from ovary wall and seeds formed from ovules. Pericarp is divisible into epicarp, mesocarp and endocarp. Tomato is a berry fruit derived from bicarpellary, syncarpous, bi-to tetralocular ovary with swollen placentae. Berry consists of a membranous skin represented by epicarp. Mesocarp is the middle fleshy part. Endocarp, septa, and placentae are pulpy and edible. All parts of the fruit, except the small seeds, are edible.

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(b) Aestivation is the arrangements of accessory floral organs (sepals or petals) in relation to one another in floral bud. It may be of open, valvate, twisted, or imbricate type. In imbricate aestivation, there is an irregular overlapping of petals by one another. It has three subtypes besides imbricate proper i.e., quincuncial, ascending imbricate, and descending imbricate or vexillary. Cassia, Pisum, etc., show imbricate aestivation.

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(c) Grass seeds are endospermic. Mango is a seeded fruit. A sterile pistil is called pistillode and a sterile stamen is called staminode. Maize grains consist of fruit wall, seed coat, endosperm, and embryo. The endosperm occupies most of the grains interior and consists of two parts, horny aleurone layer and mainly storage layers. The aleurone layer lies immediately below the grain covering and is 1-3 cell thick. Aleurone cells are thick-walled with cytoplasm filled with aleurone grains which produce enzymes during seed germination to mobilise stored nutrients.

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(d) Carrot and sweet potato are root modifications while the edible part of groundnut is seeds. Potato is an edible underground stem.

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(a) 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. All the given plants except bitter gourd, pumpkin, cucumber, guava, plum, and rose have the hypogynous flower.

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(c) In China rose the flowers are actinomorphic i.e., it can be divided into two equal radial halves in any radial plane passing through the centre; they are hypogynous, i.e., the gynoecium occupies the highest position, while the other parts are situated below it; they have twisted aestivation \(i . e\)., one margin of petal overlaps that of the next one, and so on.

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(b) The mode of arrangement of the sepals or petals with respect to one another in the floral bud is termed as aestivation. Aestivation is of different types – valvate, twisted or contorted, imbricate, quincuncial, vexillary, convolute, and plicate. In valvate aestivation, sepals or petals or tepals just touch each other without any overlapping. Calotropis, tulip, Asparagus, Colchicum, Petunia, mustard, and tobacco have valvate aestivation.

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(d) Racemose inflorescence is also called indefinite and indeterminate type. The growth of the peduncle is indefinite. Here the terminal bud will not modify into a flower. Flowers develop in acropetal succession i.e., mature flowers are towards the base and the younger ones towards the tip of the peduncle. Flowers open in centripetal succession i.e., the opening of flowers proceeds from the periphery to the centre of the inflorescence. Peduncle may be unbranched or branched. Soybean belongs to the family Fabaceae which has racemose inflorescence.

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(d) Cymose inflorescence is also called definite or determinate inflorescence. The growth of the peduncle is definite. Here, the terminal bud is modified into a flower. Flowers develop in basipetal succession, i.e., mature flowers are towards the apex and young flower buds are towards the base. Flowers open in centrifugal sequence, i.e., flowers open from centre to the periphery of the inflorescence e.g., Solanum, Ranunculus, Datura, Gossypium, etc.

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(b) Seed coat is thick in coconut seed and thin, membranous in groundnut, gram and maize seeds.

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(b) The main difference between perisperm and endosperm is that perisperm is present in seeds and endosperm is present in the developing embryo as its reserved food which is completely consumed by it during development.

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(d) Placentation is the arrangement of ovules within the ovary. It is of different types namely, marginal (pea), parietal (mustard, Argemone), axile (China rose, tomato, lemon), and free central (Dianthus, Primrose).

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(a) Cymose infloresence is present in Solanum. Cymose inflorescence is the name of determinate or definite inflorescence in which the tip of the main axis terminates in a flower and further growth continues by one or more lateral branches which also behave like the main axis.

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(c) In several species of Acacia found in the deserts of Australia the bipinnate lamina is absent Instead petiole and part of the rachis become flattened into the sickle-shaped structure for performing the function of food synthesis. Such a flattened petiole which carries out the functions of the lamina is called phyllode. The formation of phyllode is a mechanism to reduce transpiration because (i) it is vertically placed and (ii) has fewer stomata.

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(d) Gynoecium is the female reproductive organ of a flower. It may be apocarpous (pistils separated) e.g., Michelia or syncarpous (fused) e.g., tomato.

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(a) Coconut fruit is a drupe. It has a membranous epicarp, fibrous mesocarp, and stony endocarp. The endocarp encloses a single seed with brown testa that contains a small embryo and a white oily endosperm (edible part) with a watery fluid called coconut water.

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(a) This type of aestivation is seen in Fabaceae. Here, the posterior largest petal overlaps the petals that are lateral, which in turn overlap the two anterior petals.

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(c) Onion – Bulb – Underground stems -Imbricate aestivation -Axile placentation Member of Liliaceae.

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(c) Gram, arhar, sunhemp, moong, pea, and lupin belong to Family Fabaceae which is characterized by marginal placentation.

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(d) Tulip is the common name for any member of the thousands of varieties and about 100 species of bulbous perennial plants comprising the genus Tulipa of the flowering plant Family Liliaceae. A bulb is an underground vertical shoot that has modified shoot (or thickened leaf bases). A flower is regarded as a modified stem with shortened internodes and bearing at its nodes and structures that may be highly modified leaves. A flower structure forms on a modified shoot or axis with an apical meristem that does not grow continuously.

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(b) The chili pepper is the fruit of plants from the genus Capsicum which are members of the nightshade family, Solanaceae. Chili peppers are widely used in many cuisines as a spice to add heat to dishes. The substances giving chili peppers their intensity when ingested or applied topically are capsaicin and related compounds known as capsaicinoids.

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(b) Flowers of gulmohur have bilateral symmetry. So, they are called zygomorphic. Datura, mustard, and tomato have actinomorphic flowers.

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(a) 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.

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(a) Drupe is a fleshy fruit that develops from either one or several fused carpels and contains one or many seeds. The seeds are enclosed by the hard protective endocarp (pericarp) of the fruit, e.g., mango. In mango, the pericarp is well-differentiated into an outer thin epicarp, a middle fleshy edible mesocarp, and an inner stony hard endocarp.

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(b) The figure given in option (b) represents the free central placentation. In free central placentation, ovary is unilocular and ovules are borne on the axis in the center of the ovary and septa are absent. It is seen in Dianthus and Primrose.

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(d) In Alstonia, five or more leaves arises from each node, so it shows whorled phyllotaxy. The leaves are leathery, sessile, and simple which are elliptical or ovate or wedge-shaped at the base. It is used in traditional medicines.

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(d) Sweet potato is homologous to turnip as both are having the same origin i.e., both are root but modified for different functions. Sweet potato is a modified root for storage and vegetative propagation while turnip is modified for storage only.

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(b) Aleurone cells are the outer cell layer of the endosperm, usually only one cell thick in wheat and the only endosperm tissue alive at maturity. The cell layers of this layer are responsible for the de-novo synthesis of enzymes needed during germination. The chromosome number is 63 of a plant with 42 chromosomes in its root tip cells.

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(c) Eyes of potato tubers are axillary buds. As tuber is oval or spherical swollen
underground modified stem lacking adventitious roots. It possesses a number of spirally
arranged depressions called eyes. Each eye represents a node and consists of 1-3
axillary buds in the axil of small scally leaves.

Hint

(a) In opposite phyllotaxy, two leaves are borne on the opposite sides of a single node. It is of two types; (i) opposite and superposed, (ii) opposite and decussate. Ocimum, guava and Calotropis have opposite decussate phyllotaxy.