Majority of angiosperms, the pollen grains are shed from the anther at the bicelled (2-celled) stage. But in some genera (both the monocots and dicots), the generative cell divides prior to the dehiscence of the anther and pollen grain is shed at 3-celled stage Answer : (b)

Statement (i) correct: Vegetative propagation is a form of asexual reproduction. Organisms that reproduce through asexual reproduction. The new plants contain the genetic material of only one parent Statement (ii) correct: In ginger, the vegetative propagation occurs through the underground stem called rhizome. Staement (iii) correct : totipotency is the genetic potential of a plant cell to produce the entire plant. Micropropagation is the practice of rapidly multiplying stock plant material to produce many progeny plants thus totepotency heps in microprpagation as micropropagation is in vitro clonal propagation of plants from shoot tips or nodal explants. Answer : (b)

The tapetum is a specialised layer of nutritive cells found within the anther, of flowering plants, where it is located between the sporangenous tissue and the anther wall. Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat Answer : (b)

Sporopollenin occurs in the area of germ pores only is not correct as it is a major component of the tough outer (exine) walls of plant spores and pollen grains. Answer : (c)

Answer:(d)

Answer:(a)

the megaspore develops into the female gametophyte (the embryo sac) in a process called megagametogenesis. Megaspore: The female gametophyte (an oval structure in the nucellus of the ovule) of flowering plants, formed by the division of the haploid megaspore nucleus, and the site of fertilization of the egg and development of the embryo. It consists of 6 haploid cells without cell walls (2 synergidae, 3 antipodal cells, and an egg cell) and 2 haploid nuclei (polar nuclei). Sometimes the 2 haploid, polar nuclei fuse to form a single, endosperm moter cell. At fertilization, 1 male nucleus fuses with the egg nucleus to form a zygote which develops into the embryo. The second male nucleus fuses with the primary endosperm nucleus to form the endosperm nucleus. This then divides to form the endosperm. A megaspore mother cell, or megasporocyte, is a diploid cell in plants in which meiosis will occur, resulting in the production of four haploid megaspores. At least one of the spores develop into haploid female gametophytes hence 'a' not correct option Answer : (b)

Xenogamy is the transfer of pollen grains from the anther to the stigma of a different plant. Allogamy isthe fertilization of a flower by pollen from another flower, especially one on a different plant. Thus Xenogamy is a type of Allogamy Autogamy is self-fertilization, especially the self pollination of a flower. Homogamy Inbreeding can be referred to as homogamy. Cleistogamy is self-fertilization that occurs within a permanently closed flower. The main difference between allogamy and xenogamy is that allogamy is the deposition of pollen grains from the anther of the one flower on the stigma of another flower, either in the same plant or a in a different plant of the same species whereas xenogamy is the deposition of pollen grains from the anther of one flower on the stigma of a genetically different flower of the same species. Answer : (c)

Megasporogenesis: The formation of megaspores inside the ovules of seed plants Megagametogenesis is the development of a megaspore into an embryo sac Answer : (b)

> ploidy: the number of sets of chromosomes in a cell, or in the cells of an organism. A diploid female having 2n chromosomes on meiosis will produce a haploid gamete having ’n ‘ chromosomes. And tetraploid male having 4n chromosomes on meiosis will produce gamete having 2n chromosomes. When these gametes undergo fertilization, the resulting zygote will have 3n chromosomes, that is triploid in nature. N (from female) +2N(from male) = 3N(zygote) Endosperm is formed by the process of triple fusion, wherein one male gamete fuses with the two polar nuclei. In this case, the two polar nuclei are haploid but the male gamete is diploid (2n). Hence, the endosperm would be tetraploid (n + n + 2n = 4n) Answer : (a)

Cleistogamy is observed in the underground flowers of Commelina benghalensis All Ficus species are characterized by an enclosed spherical inflorescence (syconium) with a minute opening (ostiole). Each syconium also called fig contains along the inner side hundreds of unisexual flower. Figs are pollinated by wasps that belong to Hymenoptera, family Agaonidae. Anthocephalus (Kadam tree) shows Chiropterophily :flowers and open at night emit a good fragrance. other examples are e.g., Kigelia pinnata (Sausage tree), Adansonia (Baobab tree), Bauhinia megalandra, , etc. Vallisneria plants are dioecious (bearing only male or female flowers) and feature a unique aquatic pollination system Answer : (b)

The central cell in the ovule of angiosperms is present in the centre of the embryo sac. It contains two polar nuclei. The two polar nuclei get fused prior to fertilisation and form a diploid secondary nucleus. Hence, prior to fertilisation, there is one diploid secondary nucleus in the angiospermic ovule. So, the correct answer is b. Answer : (b)

Polyembryony is the phenomenon of two or more embryos developing from a single fertilized egg Polyembryony is quite common in Onion, Groundnut, Mango, Lemon, Orange. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. Answer : (b)

Pollen tube eventually reaches the micropyle of an ovule and for this purpose, it may follow one of the following three routes: 1. Porogamy- when the pollen tube enters the ovule through micropyle. It is common in most of the angiosperms. 2. Mesogamy- when the pollen tube enters through the integuments or through funiculus. 3. Chalazogamy- when the pollen tube enters through the chalazal tissues. Since, the end opposite to micropyle is chalaza, entry of pollen tube through this end will be from chalaza i.e. this will be Chalazogamy. So, the correct answer is "b". Answer : (b)

The first mitotic division in the megaspore forms two nuclei. One nucleus moves towards the micropylar end while the other nucleus moves towards the chalazal end. Then, these nuclei divide at their respective ends and re-divide to form eight nucleate stages. As a result, there are four nuclei each at both the ends i.e., at the micropylar and the chalazal end in the embryo sac. At the micropylar end, out of the four nuclei only three differentiate into two synergids and one egg cell. Together they are known as the egg apparatus. Similarly, at the chalazal end, three out of four nuclei differentiates as antipodal cells. The remaining two cells (of the micropylar and the chalazal end) move towards the centre and are known as the polar nuclei, which are situated in a large central cell. Hence, at maturity, the female gametophyte appears as a 7-celled structure, though it has 8 nucleate. Answer : (b)

Xenia (also known as the Xenia effect) in plants is the effect of pollen on seeds and fruit of the fertilized plant. The effect is separate from the contribution of the pollen towards the next generation Xenia and metaxenia terms are related with pollen and endosperm. The effect of pollen on endosperm is called xenia whereas pollen of stomatic cell lying outside the endosperm is known as metaxenia. Definition of metaxenia. : the effect of a pollen parent on the developing maternal tissues of a seed or fruit outside the embryo and endosperm due to hormones produced by the embryo and endosperm after double fertilization Answer : (c)

Allogamy is the fertilization of a flower by pollen from another flower, especially one on a different plant. Answer : (b)

Answer:(b)

Answer:(c)

Tapetum is the innermost layer and completely surrounds the sporogenous tissue. The cells of tapetum have dense cytoplasm and generally more than one nuclei. It nourishes the developing pollen grains. Endosperm is the nutritive tissue that nourishes the developing embryo. It is formed from the fusion of male gamete with the diploid secondary nucleus resulting in the formation of a triploid primary endosperm mother cell which then develops into endosperm. Integuments a tough outer protective layer, especially that of an animal or plant. Palisade parenchyma is present in the leaves and is the primary site of photosynthesis in plants. Thus, palisade parenchyma has nutritive function. Hence, among all the options given in the question, integuments is the non-nutritive structure. So, the correct answer is C. Answer : (c)

Strasburger He was the first to provide an accurate description of the embryonic sac in gymnosperms (such as conifers) and angiosperms (flowering plants), along with demonstrating double-fertilization in angiosperms. Answer : (c)

Double fertilization is the process in which two male gametes fuse with the female gamete and the secondary nucleus respectively to form the zygote and the endosperm Answer : (d)

After reaching ovary, the pollen tube enters the ovule. Pollen tube may enter the ovule by any one of the following routes : (i) Porogamy : When the pollen tube enters the ovule through micropyle. (ii) Chalazogamy : The entry of pollen tube into the ovule from chalazal region is known as chalazogamy. (iii) Mesogamy : The pollen tube enters the ovule through its middle part. Answer : (d)

Megaspore mother cell is diploid in nature. Thus, if 2n= 10, the number of chromosomes in aleurone layer will be triploid in nature. The number of chromosomes is thus, 3n = 15. Answer : (c)

Endosperm is triploid in most species (3n) 3n = 24 n= 8 Answer : (a)

Triple fusion is a fusion that involves a sperm nucleus and two polar nuclei which occurs in the double fertilization in a seed-bearing plant that results in the endosperm formation Answer : (d)

Mesogamy is a pollen tube that enters the embryo sac through the funiculus or the integument. Isogamy sexual reproduction by the fusion of similar gametes. Porogamy the fertilization of a seed plant involving passage of the pollen tube into the ovule by the micropyle. Chalazogamy a process of fertilization in which the pollen tube penetrates to the embryo sac through the tissue of the chalaza Answer : (c)

Angiosperm families, ovule is anatropous ovule - a completely inverted ovule turned back 180 degrees on its stalk. Answer : (a)

Entomophily or insect pollination is a form of pollination whereby pollen of plants, especially but not only of flowering plants, is distributed by insects Answer : (a)

Cleistogamous flowers are bisexual flowers which never open, i.e. always remain closed to each other. When anthers dehisce in the flower buds, pollen grains come in contact with the stigma of the same flower, i.e. autogamy occurs. So, these flowers produce assured seed set, even in the absence of pollinators. Answer : (d)

Each of the microsporocytes in the microsporangia undergoes meiosis, producing four haploid microspores. These develop into pollen grains, each consisting of four cells and a pair of external air sacs Thus four microsporocytes will produce 16 pollen grains Answer : (d)

Porogamy : When the pollen tube enters the ovule through micropyle. Answer : (c)

Sporopollenin is the major component of exine of spores and pollen. It is extremely resistant to non-oxidative chemicals, enzymes and strong chemical Answer : (a)

Xenogamy is fertilization of a flower by pollen from a flower on a genetically different plant. Answer : (a)

Ubisch bodies are involved in external thickening of the outer layer of pollen grain i.e. these help in exine formation. Answer : (c)

Malacophily : Pollination by slugs and snails is called malacophily. Land plants like Chrysanthemum and water plant like lemna shows malacophily. Arisaema (aroid; snake plant) is often visited by snails Answer : (d)

Palynology, scientific discipline concerned with the study of plant pollen, spores, and certain microscopic planktonic organisms, in both living and fossil form. Answer : (a)

A megaspore mother cell, or megasporocyte, is a diploid cell in plants in which meiosis will occur, resulting in the production of four haploid megaspores Reason is not correct statement Answer : (c)

Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges and rushes. Entomophily or insect pollination is a form of pollination whereby pollen of plants, especially but not only of flowering plants, is distributed by insects. Zoophily is a form of pollination whereby pollen is transferred by animals, usually vertebrates but may include invertebrates, particularly by hummingbirds and other birds, and bats, but also by monkeys, marsupials, lemurs, bears, rabbits, deer, rodents, lizards, and other animals. malacophily pollination by snails. Answer : (a)

Answer:(c)

Answer:(d)

Eusporangiate development is found in all vascular plants (Pteridophytes, Gymnosperms and Angiosperms) except Leptosporangiopsida. Leptosporangiate development is present only in some advanced Pteridophytes (members of Leptosporangiopsida called true ferns). Answer : (a)

Hydrophily A rare form of pollination in which pollen is carried to a flower by water. In vallisneria, the female flower reach the surface of water by the long stalk and the male flower or pollen grains are released into the surface of water They are carried by water currents reaching the female flowers and the stigma. In Water lily pollination takes place through wind or insect, female flower imerges above the surface of water and gets pollinated. Answer : (d)

Double fertilization, occurs only in angiosperms. Importance: It gives stimulus to the plant due to which ovary develops into fruit and ovules develop into seeds. It restores the diploid condition by fusion of haploid male and female gametes. Answer : (a)

The ovules after fertilization, develop into seeds. A seed is made up of a seed coat and an embryo. The embryo is made up of a radicle, an embryonal axis and one (wheat, maize) or two cotyledons (gram and pea). Answer : (a)

Apomixis does not involve gamete formation and fertilisation as found in amphimixis. Adventive embryo formation is a type of apomixis in which embryos are formed from diploid integumental or nuceller cells. Answer : (a)

A single large megasporocyte arises within the nucellus near the micropyle and undergoes meiotic division, resulting in a single linear tetrad of megaspores. Answer : (b)

Cross-pollination, also called allogamy, occurs when pollen is delivered from the stamen of one flower to the stigma of a flower on another plant of the same species. Answer : (c)

In angiosperms, single large megasporocyte arises within the nucellus near the micropyle and undergoes meiotic division, resulting in a single linear tetrad of megaspores. Three of the four megaspores degenerate, and the surviving one enlarges. The resulting megagametophyte produces the female gametes (eggs). This development (called megagametogenesis) involves free-nuclear mitotic divisions. Answer : (d)

The staminate flower are male flowers will give rise to two male gametes each with "t" genotype. The pistillate flower are female flowers will produce secondary nucleus with the genotype "TT". Therefore the genotype of endosperm would be t+TT ie TTt Answer : (b)