Sponsor Area
C.
fruit developed without fertilizationSponsor Area
T.S. of Anther
Fig. (A) Transverse section (B) Enlarged view of one microsporangium showing wall layers
a. The outermost is the single layer of epidermis.
b. The second layer is endothecium, where cells develop thickenings.
c. Middle layer is of 2-4 cells.
d. Tapetum, the innermost layer which provides nutrition to the developing pollen cells. The cells of tapetum may be multinucleate.
2. There are four pollen sacs.
3. There is a group of compactly arranged homogenous cells called sporogenous tissue in the centre of each sac.
Microsporogenesis and formation of pollen grains.
1. Every cell of the sporogenous tissue is a potential pollen mother cell (PMC) and can give rise to microspore tetrad/ pollen grains.
2. But some of them forego this potential and others become differentiated into the pollen mother cells or microspore mother cells.
3. Each microspore mother cell undergoes meiosis to form a cluster of four haploid cells, called microspore tetrad.
4. As the anther matures, the microspores dissociate from the tetrad and develop into pollen grains or the male gametophyte.
Fig.Microsporogenesis.
Sponsor Area
1. Self-pollination. It is also called autogamy. The pollen grains are transferred from the anther to the stigma of the same flower. e.g hibiscus.
2. Cross-pollination. It is also called allogamy. If the transfer of pollen takes place from anther to stigma of a different flower of same plant, it is known as Geitonogamy. e.g Maize.
On the other hand, if cthe transfer occurs from anther to stigma of a different flower of different plant, it is called the Xenogamy. e.g papaya.
(2) It leads to the formation of Primary endosperm nucleus which provides nutrition to the developing embryo.
(3) It restores the diploid condition.
(4) It results in combination of characters and hence variations in the offspring.
Anthers are removed before they dehisce from the flower of the female plant if it is bisexual. This step is referred to as emasculation. There is no need to remove the anthers if the flower is unisexual. The flowers are then covered with a bag of suitable size, generally made up of butter paper, to prevent contamination of its stigma with unwanted pollen. This process is called bagging.
Advantages of bagging technique
1. It is necessary for cross-breeding and to prevent pollination by unwanted species in plant breeding.
2. Commercially superior hybrid varieties can be obtained by cross pollination of different useful species.
3. It helps to avoid inbreeding depression caused by self pollination.
Emasculation is applied by plant breeders to carry out artificial hybridization. It helps them to achieve cross-pollination and prevent self pollination. It helps in producing commercially superior varieties of plant and combining desirable qualities of two plants in one by cross pollination.
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Non-endospermic Seed |
Endospermic Seed |
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1. The testa is soft and thin. 2. The endosperm is absent. 3. The cotyledons are thick. 4. The food is stored in the cotyledons. Examples : Pea, Bean and Mustard. |
1. The testa is very hard and brittle. 2. The endosperm is present. 3. The cotyledons are thin and papery. 4. The food is stored inside the endosperm. Examples : Rice, wheat, maize, castor. |
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Microsporogenesis |
Megasporogenesis |
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1. Formation of microspores and production of male gametophyte is termed micro-sporogenesis. 3. Many microspore mother cells are differentiated in a microsporangium. 4. All the four cells of the microspore tetrads are functional. |
1. Formation of megaspores , female gametophyte from megaspore mother cells is called megasporogenesis. 2. It occurs in the nucellus of the ovule/megasporangium. 3. Only one megaspore mother cell is differentiated in a megasporangium. 4. Only one of the four cells in the megaspore tetrad continues to grow. |
The type of cell division that occurs during these events is Meiosis or Reduction division which produces haploid gametes from diploid cells.
The structures formed at the end of the two events are2. Out of 7 cells of mature female gametophyte, the egg cell fuses with male gamete to form zygote, one synergid degenerates and the other synergid directs the pollen tube entry, the central cell fuses with the male gamete to form triploid primary endosperm nucleus and the three antipodals degenerate before or after fertilization.
Example. Viola (common pansy), Oxalis and Commelina.
(ii) Cleistogamous flowers cannot cross pollinate because the flowers do not open at all. In such flowers anthers and stigma lie close to each other. When anther dehisces in the flower the pollen grain come in close contact with the stigma to affect self-pollination. Thus there is no chance of cross pollination and only self pollination occurs.
1. Unisexuality. The Plants bear unisexual flowers i.e. stamens and carpels occur in different flowers. They may be present on same plant e.g., in maize or on different plants e.g. in Papaya. The first condition is called monoecious and second is called dioecious. Since the male and female flowers are different the chances of self pollination are less.
2. Dichogamy. When stamens and carpels of bisexual flowers mature at different times, it is called as dichogamy. If stamens mature first it is called protandrous condition, or if carpels mature first it is called protogynous condition. since the stamens and the carpels mature at different time they cannot self pollinate.
What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?
It occurs in embryo sac. Triple fusion occurs when during fertilization the other male nuclei moves towards the central two polar nuclei and fuse with them forming 3n primary endosperm nucleus.
Nuclei involved are two polar nuclei and one nucleus of male gamete.
In the mature ovule, within the nucellus towards the micropylar end is a large cell called embryo sac. It is also called female gametophyte. It contains cytoplasm, two free nuclei and six small cells. Two free nuclei fuse to form secondary nucleus. Out of these three cells constitute egg apparatus (two synergids and one oosphere or egg cell). The other three cells lie at chalazal end of embryo sac and are called antipodal cells. They are small and enclosed in thin cell walls.
In egg apparatus egg fuses with male gamete to form zygote or oospore which later gives rise to embryo. Synergids help in fertilization. Secondary nucleus fuses with the second male gamete to form primary endosperm nucleus which later on forms endosperm.
The three antipodal cells degenerate.
Structure of typical embryo sac.
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Self-pollination |
Cross-pollination |
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1. It is transference of pollen grains from anther to the stigma of the same flower. 2. Self-pollination always occurs through touch or wind. 3. Both anthers and stigmas mature simultaneously. 4. It can occur in closed flowers. 5. Race is almost constant i.e., homozygous. 6. It gives rise to pure lines. 7. It preserves the parental characters. |
1. It is transference of pollen grains from anther to the stigma of another flower of another plant. 2. Cross-pollination always occurs through an external agent. 3. The anthers and stigmas mature at different times. 4. It occurs only when the flowers are open. 5. The race is changing i.e. heterozygous. 6. It gives rise to offspring having variations or hybrids. 7. It does not preserve the parental characters. |
These flowers have the following characters :
(1) The size of flower is very small.
(2) Bright coloured corolla, nectar glands and fragrance are absent.
(3) Flowers are grouped together in clusters.
(4) Pollen grains are produced in large quantities.
(5) Versatile fixation of anthers aid idispersal of pollen grains by air.
(6) Pollen grains are dry, smooth and very light. e.g. coconut palm, date palm, Cannabis (Bhang), maize and grasses.
Characters of Entomophilous flowers
(1) The flowers are of large size.
(2) Corolla of flowers is brightly coloured to attract insects. Bracts may become bright coloured
(3) If the flowers are small they are grouped together to form inflorescence which helps attracting insects.
(4) They may produce nectar to lure insects.
(5) The pollen grains are heavy with rough and spiny surface so that they stick to the insects body.
(6) The stigma surface is sticky.
(7) the flowers have fragrance to attract insects . some have foul odour to attract insects like flies and beetles.
Fig.(A)enlarged view of an egg apparatus showing entry of pollen tube into a synergid
(B) Discharge of male gametes into a synergid and the movements of the sperms, one into the egg and the other into the central cell.
1. Protection of seeds in the early stages till they become fully mature.
2. Dispersal of seeds.
3.They provide nutrition to germinating seedlings. On their decay provide raw material for the benefit of developing seedling.
4. Many fruits are consumed by animals and human being as a source of food. They act as a source of vitamins , glucose, proteins etc.
1. The fruit protects seeds against hostile climate conditions and animals.
2. It aids in dispersal of seeds to distant places through wind, water and animals.
Economic importance of fruits.
1. Fruits are eaten as food by man and other animals.
2. They are source of sugars, pectin, organic acids, vitamins and minerals.
3. Food grains of wheat, rice, maize constitute a staple food as cereals.
(a) Integument forms seed coat.
(b) Ovary wall forms fruit wall.
(c) Egg cell forms embryo.
(d) Secondary nucleus forms endosperm.
(e) Antipodal cells degenerate.
(a) hypocotyl and epicotyl
(b) Coleoptile and coleorhiza
(c) Integument and testa
(d) Perisperm and pericarp.
(a) Hypocotyl is part of embryonic axis below level of cotyledons. It terminates with the radicle or root tip where as Epicotyl is part of embryonic axis above the level of cotyledon. It terminates with the plumule or stem tip.
(b) Coleoptile is hollow foliar sheath that surrounds the plumule where as Coleorhiza is a sheath enveloping the radical or root cap.
(c) Integument is the protective covering around ovule. It is thin and living. It is formed before fertilization where as Testa is outer covering of seed coat. It is non-living. It is formed after fertilization
(d) Perisperm is remnant of nucellus in a seed. It is dry where as Pericarp is wall of ripened ovary or fruit and may be fleshy or dry.
In case of apple thalamus forms the fruit.
Oranges, lemon , water melon , grapes and guavas are certain economically important fruits which can be grown by inducing parthenocarpy using growth hormones to obtain seedless fruits without fertilization.
During microsporogenesis, the cells of tapetum provide various enzymes, hormones, amino acids and other nutritive materials to the dividing microsporocytes.
The main functions of tapetum are :
1. Transportation of nutrients into inner side of anther.
2. Secretion of enzymes and hormones.
3. It helps in the formation of exine which is composed of sporopollenin.
4. It provides nutrition to the developing pollen grain.
Importance of Apomixis
1. It helps in producing hybrid seeds.
2. It is cost effective and time efficient.
3. It helps in the production of hybrid varieties with increased yield.
4. It helps preserve the good characters. As their is no seggregation the farmers can use the seeds again and again for new crops.
Draw labelled structures of some selected seeds.
Seeds of angiosperm:
Fig. Seeds of angiosperm.
1. Unisexuality. The flowers are unisexual i.e. stamens and carpels occur in different flowers. They may be present on same plant e.g., in maize or on different plants e.g. in Papaya. The first condition called monoecious and second is called dioecious.
2. Dichogamy. When stamens and carpels of bisexual flowers mature at different times, it is called as dichogamy. If stamens mature first it is called protandrous condition, or if carpels mature first it is called protogynous condition. Dichogamy prevents self-pollination and ensure cross-pollination.
3. Self sterility. In orchids, pollen grains of one flower do not geminate on stigma of the same flower. This is called self-sterility. The pollen grains germinates on the stigma of some other plant and thus ensure cross-pollination.
4. In some species the anther and stigma are placed at different levels so that the pollen does not come in contact with the stigma of the same flower.
5. Plants bears flowers which have characteristics to favour cross pollination like attractive color, smell, may produce nectar. be very light and feathery pollen grains, sticky stigma etc .
(i) Funiculus is stalk-like structure by which ovule is attached to the placenta.
(ii) Hilum. It is the point of attachment of the body of the ovule with the funiculus.
(iii) Raphe. It is the longitudinal ridge formed by lengthwise fusion of funiculus with the body of ovule in a typical anatropous ovule.
(iv) Nucellus. It is a mass of diploid cell called megas-porangium. It provides nourishment in the development of embryo sac.
(v) Embryo sac. It is the female gametophyte which contains the egg apparatus, antipodal and polar nuclei.
(vi) Integuments form seed coats i.e. testa and tegmen.
(vii) Micropyle. It is small opening which is left by the integument in the ovule for the passage of pollen tube into the ovule.
(viii) Chalaza. The basal region of ovule from where the integuments arise is called chalaza.
(vii) Micropyle. It is small opening which is left by the integument in the ovule for the passage of pollen tube into the ovule.
(viii) Chalaza. The basal region of ovule from where the integuments arise is called chalaza.
V.S. of mature ovule to show various parts.
Development of embryo.
The zygote undergoes a series of mitotic divisions to form a multicellular, undifferentiated embryo. At the micropylar end there develops a basal stalk or suspensor, which disappears after a very short time and has no obvious function in angiosperms. At the chalazal end (the region opposite the micropyle) is the embryo proper. Differentiation of the embryo—e.g., the development of cells and organs with specific functions—involves the development of a primary root apical meristem (or radicle) adjacent to the suspensor from which the root will develop and the development of one cotyledon (in monocotyledons) or two cotyledons (in dicotyledons) at the opposite end from the suspensor. A shoot apical meristem then differentiates between the two cotyledons or next to the single cotyledon and is the site of stem differentiation. The mature embryo is a miniature plant consisting of a short axis with one or two attached cotyledons. An epicotyl, which extends above the cotyledon, is composed of the shoot apex and leaf primordia; a hypocotyl, which is the transition zone between the shoot and root; and the radicle
Fig. Stages of embryo development in a (dicot) angiosperm.
Describe apomixis , parthenocarpy and polyembryony
1. Apomixis (Agamospermy). It is a modified form of reproduction in which seeds are formed without fusion of gametes. It includes the process whereby a diploid cell of nucellus develops into an embryo, giving a diploid seed with a genetic constitution identical to the parent. It is helpful in theproduction of hybrid seeds
2. Parthenocarpyis the condition where the fruits are formed without fertilization. Seedless varieties of gfruits can be obtained.
3. Polyembryony. Formation of more than one embryo in the seed. Lemon, oranges are some of examples. Polyembryony is very common among conifers.
Sponsor Area
Pollen germination starts with the pollen grain landing on stigma. The cell of the pollen grain divides into two cells one of these is smaller in size and called generative cell and bigger one the tube cell. The intine grows out through the germ pore and form pollen tube. It grows into the tissue of the style towards the ovary. By this time the tube nucleus degenerates and the generative nucleus divides to form two male gametes . The pollen tube bursts open and the male gametes are released one of which then fuse with the egg cell and other nuclei with two polar nuclei.
Germination of pollen grain and formation of male gametophyte in an angiosperm.
Development of female gametophyte
1. The functional megaspore undergoes a mitotic division forming the 2-nucleate embryo sac.
2. Two successive mitotic divisions in each of these two nuclei result in the formation of an 8-nucleate embryo sac.
3. Cell wall formation starts at the eight-nucleate stage, resulting in the formation of a typical female gametophyte.
4. Three cells that is 2 synergids and 1 egg cell are grouped together at the micropylar end to form the egg apparatusl.
5. Three cells are grouped together at the chalazal end; and are called antipodal cells. The remaining two move to the centre and are called polar nuclei.
6.Thus, a typical angiosperm embryo sac is 8-nucleate and 7-celled.
Fig. Development of embryosac.
Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
The pollen grain or the male gametophyte develops inside the pollen sacs of the anther. While the female gametophyte or the egg develops inside the ovule.
Explain any three advantages that seeds offer to angiosperms.
Seeds offer the following advantages to angiosperms:
(i) Seed formation is more dependable as the reproductive processes like pollination and fertilisation are independent of water.
(ii) The hard seed coat protects the young embryo from harsh environmental conditions.
(iii) Seed have better adaptive strategies for the dispersal to new habitats.
Coconut palm is monoecious, while date palm is dioecious. Why are they so called?
Coconut palm is monoecious because both male and female flowers are borne on the same plant.
Date palm is dioecious because male and female flowers are borne on different plants. A single plant has either male flowers or female flowers.
Draw a sectional view of human ovary and label the different follicular stages, ovum and Corpus luteum.
Diagram showing sectional view of a mature embryo sac of an angiosperm
(a) Draw a diagrammatic sectional view of a mature anatropous ovule and label the following parts in it:
(i) that develops into seed coat.
(ii) that develops into an embryo after fertilization.
(iii) that develops into an endosperm in an albuminous seed.
(iv) through which the pollen tube grains entry into the embryo sac.
(v) that attaches the ovule to the placenta.
(b) Describe the characteristic features of wind pollinated flowers.Mature anatropous ovule
(b) Characteristics of wind pollinated flowers:
(i) Large number of pollen grains are produced.
(ii) Pollen grains are light and non-sticky.
(iii) Well exposed stamens so that pollen grain are easily dispersed.
(iv) Large and feathery stigma to trap pollen grains.
Mention the unique flowering phenomenon exhibited by Strobilanthus kunthiana (neelakuranaji).
Strobilanthus kunthiana exhibits the unique flowering phenomenon that it flowers once in 12 years.
Where is sporopollenin present in plants? State its significance with reference to its chemical nature.
Sporopollenin is present in exine of pollen grains in plants. It is one of the most resistant organic substances and can withstand high temperature, strong acids and alkali. No enzyme has been found that degrades sporopollenin is so far known. This sporopollenin helps the pollen grain to be well preserved.
Differentiate between albuminous and non-albuminous seeds, giving one example of each.
The differences between albuminous and non-albuminous seeds are as under:
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Albuminous seeds |
Non-albuminous seeds |
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These seeds have endosperm. |
These seeds do not have endosperm because it is consumed by the growing embryo. |
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Examples: wheat and maize |
Examples: pea and beans |
Following is the labelled diagram of a male gametophyte of an angiosperm.
Sporopollenin is considered to be the most resistant organic material because it is chemically very stable and it can withstand high temperatures, acidic and alkaline conditions, and enzymes. No enzyme that degrades sporopollenin is so far known.
State what is apomixis. Comment on its significance. How can it be commercially used?
Apomixis is a form of asexual reproduction in which seeds are formed without fertilisation. It is a form of asexual reproduction that mimics sexual reproduction.
Significance:
Apomixis allows certain species of plants belonging to Asteraceae, and grasses to produce seeds which do not produce seeds by the process of fertilisation.
Name the part of the flower which the tassels of the corn-cob represent.
Tassels of the corn represent stigma and the style of the flower.
(a) Explain the different ways apomictic seeds can develop. Give an example of each.
(b) Mention one advantage of apomictic seeds to farmers.
(c) Draw a labelled mature stage of a dicotyledonous embryo.a. Different ways by which we can develop apomictic seeds include-
1. Formation of diploid egg i.e embryo without undergoing reduction division or fertilization e.gAsteraceae
2. Some nuclear cell divides surrounding the embryo sac divide continuously surrounding before protrude into embryo sac ultimately develop into embryo e.g Mango
b. Advantage of apomitic seeds for farmers include reduce cost of seed purchase, They can keep the hybrid seeds once purchases for next season.
(c)
How do the pollen grains of Vallisneria protect themselves?
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Perisperm |
Endosperm |
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Perisperm is the remnant of nucellus which are persistent. It encloses the embryo and provides nourishment to it in certain seeds. |
Endosperm is the tissue formed after double fertilisation. It surrounds, stores food and provide nourishment to the embryo in an angiosperm seed. |
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It is diploid in nature. |
It is triploid in nature because it is formed as a result of triple fusion. |
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Example- Black pepper |
Example- Wheat |
Out of many papaya plants growing in your garden, only a few bear fruits. Give reason.
Papaya is dioecious because the staminate and pistillate flowers are born on two different plants. Self fertilization is not found in papaya, thus in different plants the flower may be developing at different time and that is why few plants having fruits
(a) Explain the post-pollination events leading to seed production in angiosperms.
(b) List the different types of pollination depending upon the source of pollen grains.
(a) Pollination is the process of transfer of pollen grains from the anther to stigma.
i. When the pollen grains fall on the stigma, the pollen tube enters one of the synergids and releases two male gametes.
ii. One of the male gametes moves towards the egg cell and fuses with it to form zygote.
iii. The other male gamete fuses with the two polar nuclei and forms the primary endosperm nucleus. This is termed as triple fusion.
iv. After the triple fusion, the central cell becomes the primary endosperm cell (PEC). The primary endosperm nucleus gives rise to endosperm, while the zygote develops into an embryo.
v. Seeds are the fertilised ovules that are developed inside a fruit.
vi. The integuments of ovules harden to form the seed coat, and the micropyle facilitates the entry of oxygen and water into the seed.
b) Depending on the source of pollen grains, pollination can be divided as follows:
i. Autogamy - When the pollen grains are transferred from anther to stigma of the same flower. Autogamy requires the anther and the stigma to in lie close proximity and also requires synchrony between the pollen release and the stigma receptivity. For example - plants like Viola and Oxalis produce two kinds of flowers: Chasmogamous flowers (with exposed anther and stigma) and cleistogamous flowers (plants that do not open at all and in which only autogamy occurs).
Geitonogamy - It is the transfer of pollen grains from the anther of one flower to the stigma of another flower on the same plant. Genetically, it is similar to autogamy, but it requires pollinating agents like winds, water or insects.
Xenogamy - It is the transfer of pollen grains from the anther to the stigma of a different plant.
A. Draw a labelled diagram of L.S. of an embryo of grass (any six labels).
B, Give reason for each of the following:
(i) Anthers of angiosperm flowers are described as dithecous.
(ii) Hybrid seeds have to be produced year after year.
(A) L.S. of an embryo of grass.
. 
B
i. Each anther of the angiosperm flower is bilobed in nature with two layered protection called theca (dithecous). Each theca is separated by longitudinal grooves. Bilobed nature is distinct in transverse section, microsporangia is located at the corners of the tetragonal structure.
State the importance of water to plants.
Water is important for plants because of the following reasons:
(i) Water helps in the germination of seeds.
(ii) Water helps in the process of photosynthesis by which plants prepare their food.
(iii) Water helps in the transport of nutrients and minerals from the soil to the plants.
(iv) Water helps in the maintenance of the plant structure by providing the appropriate pressure to the plant tissues
(v) Water provides habitat in the form of ponds, rivers, lakes and sea for a large number of plants.
Differentiate between:
Absortion Spectrum and Action Spectrum
Differentiate between:
Racemose and cymose inflorescence
A pollen grain in angiosperm at the time of dehiscence from an anther could be 2-celled or 3-celled. Explain. How are the cells placed within the pollen grain when shed at a 2-celled stage ?
In majority angiosperms, pollens are released in 2-celled stage whereas in other species, the generative cell divides into 2 male gametes & forms 3-celled stage. When the pollen grain is shed at 2-celled stage - it has two unequal cells - bigger vegetative cell and smaller generative cell.
(a) Can a plant flowering in Mumbai be pollinated by pollen grains of the same species growing in New Delhi ? Provide explanations to your answer.
(a) It is possible by Artificial Hybridisation where pollen grain of one flower is introduced artificially on the stigma of another flower. But there should not be self-incompatibility.
* For this in One flower emasculation is removal of anthers & by choice by then flower is bagged.
* After some time, the bag is removed and then desired pollen grains are introduced on its stigma.
(a) When a seed of an orange is squeezed, many embryos, instead of one are observed. Explain how it is possible.
(b) Are these embryos genetically similar or different ? Comment.
(a) It is due to polyembryony. Occurrence of more than one embryos in a seed is called as POLYEMBRYONY. In orange, the nucellar cells, synergid or integument cells develops into a number of embryos of different sizes. eg : - Citrus.
* Sometimes formation of more than one egg in an embryo sac can lead to polyembryony.
(b) In such embryos parental characters are maintained hence they are genetically similar. In this process, there is no segregation of characters in the offspring (progeny).
Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy.
Autogamy: Transfer of pollen grains from the anther to the stigma of the same flower.
Geitonogamy: Transfer of pollen grains from the anther to the stigma of another flower of the same plant.
Two devices that prevent both autogamy and geitonogamy are:
(i) Self – incompatibility: This is a genetic mechanism & prevents self-pollen from fertilising the ovules by inhibiting pollen germination or pollen tube growth in the pistil.
(ii) Dioecious plants: Male and female flowers are present on different plants, that is each plant is either male or female.
Explain the events up to double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm.
The events seen after the pollen tube enters one of the synergids in an ovule are as follows :
Which one of the following statements is not true?
Exine of pollen grains is made up of sporopollenin
Pollen grains of many species cause severe allergies
Stored pollen in liquid nitrogen can be used in the crop breeding programmes
Tapetum helps in the dehiscence of anther
D.
Tapetum helps in the dehiscence of anther
Tapetum is the inner layer of microsporangium which provides nourishment to developing pollen grains after meiotic division.
In bryophytes and pteridophytes, transport of male gametes requires
insects
birds
water
wind
C.
water
In some primitive plants like pteridophytes and bryophytes water is the medium through which the male gametes are transferred to the female reproductive organ for fertilsation.
Proximal end of the filament of stamen is attached to the
connective
placenta
thalamus
anther
C.
thalamus
The proximal end is attached to the thalamus and the distal end bears the anthers
The coconut water from tender coconut represents
fleshy mesocarp
free-nuclear proembryo
free-nuclear endosperm
endocarp
C.
free-nuclear endosperm
Coconut milk represents free-nuclear endosperm where the division of primary endosperm nucleus is not followed by formation of cell walls, thus nucleus remains in liquid form
Whic of the following statements is not correct?
Insects that consume pollen or nectar without bringing about pollination are called pollen nectar robbers
Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil
Some reptiles have also been reported as pollinators in some plant species
Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style
D.
Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style
Pollen grains of others species are not compatible and do not germinate on the stigma of the flower of a different species.
Seed formation without fertilisation in flowering plants involves the process of
budding
Somatic hybridisation
Apomixis
Sporulation
C.
Apomixis
Apomixis is the special mechanism found in flowering plants to produce seeds without fertilisation.
Megasporangium is equivalent to
embryo sac
fruit
nucellus
ovule
D.
ovule
An Ovule (megasporangium) generally has a single embryo sac formed from a megaspore through reduction division. It is small structure attached to the placenta by means of a stalk called funicle.
Ovule →Megaspore Mother Cell (MMC) by meiosis →Megaspore
Each has one or two protective envelopes called integuments. Nucellus is a mass of cells enclosed with the integuments. Fruits develop from the ovary of a flower, other floral parts degenerate and fall off.
Read the following statements (IV) and answer the question which follows them
I. In liverworts, mosses and ferns gametophytes are free living.
II) Gymnosperms and some ferns are heterospores.
III) Sexual reproduction in Fucus, Volvox and Albugo is oogamous.
IV) The sporophyte in liverworts is more elaborate than that in mosses.
How many of the above statements are correct?
One
Two
Three
Four
C.
Three
The statement, I II and III are correct. In IV-sporophyte in mosses is more elaborate than in liverworts. V-Pinus is a monoecious plant, producing male and female cones every year.In Marchantia, plant body is strictly dioecious and isomorphic. Sex organs are found in specialised sexual receptacles called anthridiophore and archegoniophore.
Which one of the following statement is correct?
Hard outer layer of pollen is called intine
Sporogenous tissue is haploid
Endothecium produces the microspores
Tapetum nourishes the developing pollen
D.
Tapetum nourishes the developing pollen
The tapetum is the innermost layer of microsporangium. It nourishes the pollen grains. The inner wall of the pollen grain is called intine. Endothecium is the wall around the microsporangium, which provide protection and help in dehiscence of anther to release the pollen. The sporogenous tissue is diploid. It undergoes meiotic division to form microspore tetrads.
Product of sexual reproduction generally generates
longer viability of seeds
prolonged dormancy
new genetic combination leading to variation
large biomass
C.
new genetic combination leading to variation
Sexual reproduction leads to new genetic combination leading to variation in new products. The longer viability of seeds, prolonged dormancy and large biomass are not related to sexual reproduction.
Advantage of cleistogamy is
higher genetic variability
more vigorous offspring
no dependence on pollinators
vivipary
C.
no dependence on pollinators
In cleistogamous flowers, anthers and stigma lie close each other. When anthers dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, these flowers produce assured seed set even in the absence of pollinators. The higher genetic variability and more vigorous offsprings are the produced to variations obtained by sexual reproduction. Vivipary relates to the birth of young babies from mammals.
Perisperm differs from endosperms in
being a haploid tissue
having no reserve food
being a diploid tissue
its formation by fusion of secondary nucleus with several sperms
C.
being a diploid tissue
In some seeds like black pepper and beet remnants of nucellus are also persistent this persistent nucellus is called perisperm.The cells of endosperm tissue are filled with reserve food materials and are used for the nutrition of the developing embryo. The main difference is perisperm is present in seed and endosperm is present in developing embryo as its reserved food which is completely consumed by is during development.
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Which one of the following is not the function of the placenta? It
facilitates the supply of oxygen and nutrients to the embryo
secretes oestrogen
facilitates removal of carbon dioxide and waste material from embryo
secretes oxytocin during parturition
D.
secretes oxytocin during parturition
Which is Mendelian idea depicted by a cross in which the F1 generation resembles both the parents?
Incomplete dominance
Law of dominance
Inheritance of one gene
Codominance
D.
Codominance
In Codominance, both alleles of a pair express themselves fully in F1 hybrid, so, it resembles both the parents. In incomplete dominance, the two genes of an allelomorphic pair are not related as dominant or recessive but each of them expresses itself partially. Law of dominance states that when a cross is made between two homozygous individuals considering a contrasting trait of simple character then the trait that appears in F1 hybrids is called dominant. Inheritance of one gene is based the on crossing between single traits.
Filiform apparatus is characteristic feature of
Generative cell
Nucellar embryo
Aleurone cell
Synergids
D.
Synergids
Filiform apparatus are finger-like projections present at the micropylar end of synergids of embryo sac.
In angiosperms, microsprogenesis and megasporogenesis
occur in anther
form gametes without further divisions
Involve meiosis
occur in ovule
C.
Involve meiosis
Both event microsporogenesis and megasporogenesis involve the process of meiosis which results in the formation of haploid gametes from the microspore or megaspore mother cells.
Flowers are unisexual in
Pea
Cucumber
China rose
Onion
B.
Cucumber
Cucumber is a member of the family - Cucurbitaceae. In the members of this family, the flowers are unisexual, with male and female flowers on different plants (dioecious) or on the same plant (monoecious).
Placenta and pericarp are both edible portions in
apple
banana
tomato
potato
C.
tomato
Tomato is botanically a fruit but it is considered as a vegetable for various purpose. It is rich in lycopene. Its edible parts are both placenta and pericarp. The placenta is the connecting tissue which supplies nutrition for embryo and pericarp is the remains of the ovular wall.
Which of the following statements is correct?
The seed in grasses is not endospermic
Mango is a parthenocarpic fruit
A proteinaceous aleurone layer is present in maize grain
A sterile pistil is called a staminode
C.
A proteinaceous aleurone layer is present in maize grain
A proteinaceous aleurone protein layer of maize start developing approximately 10-15 day after pollination in the stack that takes 40 days for the aleurone to mature completely. Thus is the correct statement. Correct sentence for other options are
a) Seed in grasses are endospermic
b) Banana is a parthenocarpic fruit
c) Sterile pistil is called pistillode
Coconut water from a tender coconut is
Immature embryo
Free nuclear endosperm
Innermost layers of the seed coat
Degenerated nucellus
B.
Free nuclear endosperm
The coconut water from tender coconut that we are familiar with, is nothing but free nuclear endosperm (made up of thousands of nuclei) and the surrounding white kernel is the cellular endosperm. In the most common types of endosperm development, the Primary Endosperm Nucleus (PEN) undergoes successive
Which one of the following fruits is parthenocarpic?
Brinjal
Apple
Jackfruit
Banana
D.
Banana
Parthenocarpy is a process of developing fruits without involving fertilisation/seed formation. Therefore, the seedless varieties of economically important fruits like orange, banana, watermelon, lemon, etc. are produced using this technique. This technique involves inducing fruit formation by the application of plant growth hormones such as auxins.
Male gametophyte in angiosperms produces
Two sperms and a vegetative cell
Single sperm and a vegetative cell
Single sperm and a two vegetative cells
Three sperms
A.
Two sperms and a vegetative cell
Pollen grain or male gametophyte in angiosperms contain one generative cell. The generative cell. The generative cell further divides mitotically to form two male gametes(sperms). So, a mature male gametophyte in angiosperms contains two sperms and one vegetative cell.
Geitonogamy involves
Fertilisation of a flower by the pollen from another flower of the same plant
Fertilisation of a flower by the pollen from the same flower
Fertilisation of a flower by the pollen from a flower of another plant in the same population
Fertilisation of a flower by the pollen from an another plant belonging to a distant population
A.
Fertilisation of a flower by the pollen from another flower of the same plant
Geitonogamy is a type of self-pollination. IN other word geitonogamy is a transfer of pollen grain from the anther of one flower of the either same or genetically similar plant.
Pollen tablets are available in the market for
In vitro fertilisation
breeding programmes
supplementing food
Ex situ conservation
C.
supplementing food
The pollen grain is rich in nutrients. In recent years pollen tablets are used as food supplements as they are rich in isoprotein. It is used for bleeding problems, coughing, vomiting, bloody diarrhoea and brain haemorrhage. Pollen tablets are also used by athletes for instant energy.
Function of filiform apparatus is to
recognise the suitable pollen at the stigma
stimulate the division of generative cell
produce nectar
guide the entry of pollen tube
D.
guide the entry of pollen tube
Filliform apparatus is the finger-like projections of synergids which help in the absorption and conduction of food materials from the nucleus into embryo sac and directs the pollen tube towards embryo sac by secreting some chemicals.
Non -albuminous seed is produced in
maize
castor
wheat
pea
D.
pea
Non-albuminous or non-endospermic seeds are those in which cotyledons are usually smaller and less developed. Such seeds are termed when most or all of the endosperm is used up much before germination. Thus, out of all examples given in the option, the non-albuminous seed is produced in pea( i.e., Pisum sativum)
Both, autogamy and geitonogamy are prevented in
papaya
cucumber
castor
maize
A.
papaya
Autogamy involves pollination within the same flower, while geitonogamy involves transfer of pollen grains from the anther of one flower to the stigma of another flower of the same plant. Both the process are prevented in papaya because it is dioecious plant(i.e, male and female sex organs are borne on separate plants) and it always needs cross-pollination.An organic substance that can withstand environmental extremes and cannot be degraded by any enzyme is
cuticle
sporopollenin
lignin
cellulose
B.
sporopollenin
Sporopollenin is a fatty substance present in the exine of pollen grains. It is resistant to microbial and chemical decomposition and can withstand the extreme environmental conditions. Due to presence of sporopollenin, pollen grains are well preserved during fossilization.
Even in absence of pollinating agents seed-setting is assured in
Commellina
Zostera
Salvia
fig
A.
Commellina
Commellina benghalensis or kankauoa bears aerial, chasmogamous (stigma and anthers exposed to pollinating agents), insect pollinated flowers and underground cleistogamous flowers. Cleistogamous flowers are bisexual flowers which never open, i.e., always remain closed. In such flowers the anthers and stigma lie very close 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.
Assisted reproductive technology, IVF involves transfer of
ovum into the Fallopian tube
zygote into the Fallopian tube
zygote into the uterus
embryo with 16 blastomeres into the Fallopian tube
B.
zygote into the Fallopian tube
In vitro fertilisation is a process in which an egg is fertilised by sperm outside the women's womb. IVF is a major treatment for infertility. The process involves hormonally controlled ovulatory process, removing ova from the woman's ovaries and letting sperm fertilise them in a fluid medium.
The zygote or the embryo up to 8- celled stage in then transferred into the patient's Fallopian tube with the zygote is more than 8 blastomere stage, it is placed directly into the uterus.
The coconut water and the edible part of coconut are equivalent to
endosperm
endocarp
mesocarp
embryo
A.
endosperm
The coconut water obtained from the tender coconut is nothing but free nuclear endosperm (made up of thousands of nuclei) and the surrounding white kernel is the cellular endosperm.
What is the function of germ pore?
Emergence of radicale
Absorption of water for seed germination
Initiation of pollen tube
Release of male gametes
C.
Initiation of pollen tube
The pollen grain has two layers - outer exine and inner intine. Exine is made up of highly resistant sporopollenin while intine is pectocellulosic. At certain places exine is thin or absent called germpore or germinal furrow. After reaching on stigma the pollen grain absorbs water and nutrients from the stigmatic secretion through its germ pore. The tube or pollen grain through one of the germ pores or germinal furrows to form a pollen tube.
Which one of the following statements is wrong?
When pollen is shed at two-celled stage, double fertilization does not take place
Vegetative cell is larger than generative cell
Pollen grains in some plants remain viable for months
Intine is made up of cellulose and pectin
A.
When pollen is shed at two-celled stage, double fertilization does not take place
Before pollination the protoplast of pollen grain divides into two unequal cells small generative cell and large tube or vegetative cell. In some species the generative cell divides into two male gametes prior to dehiscence of pollen grain. Therefore at the time of pollination the pollen grain is either 2-celled or 3-celled.
Which one of the following may require pollinators, but is genetically similar to autogamy?
Geitonogamy
Xenogamy
Apogamy
Cleistogamy
A.
Geitonogamy
Geitonogamy is functionally cross pollination but genetically it is autogamy because in geitonogamy the pollens come from the same plant. Pollens are being transferred to the stigma of one flower to another flower of /on the same plant, which is genetically same. Therefore, geitonogamy is a cross pollination phenomenon but is equivalent to autogamy genetically.
Which one of the following statements is not true?
Pollen grains are rich in nutrients, and they are used in the form of tablets and syrups
Pollen grains of some plants cause severe allergies and bronchial afflictions in some people
The flowers pollinated by flies and bats secrete foul odour to attract them
Honey is made by bees by digesting pollen collected from flowers
D.
Honey is made by bees by digesting pollen collected from flowers
Honey is made by bees by nectar and pollens. Bees collect pollen and nectar in the spring when most flowers and plants are in bloom. They collect them in their stomach about an hour, the nectar mixes with the proteins and enzymes produced by bees, which convert nectar into honey.
Which one of the following statements is not true?
Pollen grains are rich in nutrients, and they are used in the form of tablets and syrups
Pollen grains of some plants cause severe allergies and bronchial afflictions in some people
The flowers pollinated by flies and bats secrete foul odour to attract them (c) Honey is made by bees by digesting
Honey is made by bees by digesting pollen collected from flowers
D.
Honey is made by bees by digesting pollen collected from flowers
Honey is made by nectar and pollens. Bees collect pollen and nectar in the spring when most flowers and plants are in bloom. They collect them in thier stomach but an hour, the nector mixes with the proteins and enzymes produced by bees, which convert nectar into honey.
Which of the following are the important floral rewards to the animal pollinators?
Colour and large size flower
Nectar and pollen grains
Floral fragrance and calcium crystals
Protein pellicle and stigmatic exudates
B.
Nectar and pollen grains
Nectar and pollen grains are important floral rewards to the animal pollinators such as moths, butterflies, wasps, bees, birds, etc. They visit the flowers for nectar, edible pollen grains and shelter and nursing (as in fig and Yucca). Besides, edible floral parts and young seeds are also usual rewards for pollinatiors. In turn, while visiting flowers, they come in contact and adhere pollen grain and bring about pollination, which they visit another flower.larger but to have smaller sex organs
larger and to haver larger sex organs
smaller and to have smaller sex organs
smaller but to have larger sex organs
C.
smaller and to have smaller sex organs
As we proceed from thallophyta to angiosperms, there is gradual reduction in gametophte with reduced size of sex organs. From thallophyta to angiosperms, there is progressive elaboration of sporophytes.
| Phase | Thallophyta | Bryophyta | Pteridophyta | Gymnosprems | Angiosperms |
| Gametophyte(%) | 90 | 75 | 50 | 25 | 10 |
| Sporophyte(%) | 10 | 25 | 50 | 75 | 90 |
Which one of the following statements is correct?
Seeds of orchids have oil-rich endosperm
Placentation in primrose is basal
Flower of tulip is a modified shoot
In tomato, fruit is a capsule
C.
Flower of tulip is a modified shoot
Flower is highly condensed and modified shoot meant for sexual reproduction (Dr. Goethe; 1790). During the course of evolution, the nodes of the axis of shoot came in contact so, that internodes got reduced, and leaves got modified and specialized to form floral leaves.
Filiform apparatus is a characteristic feature of
egg
synergid
zygote
suspensor
B.
synergid
Filiform apparatus is finger-like projection of the cell membrane of synergids or help cells at the micropylar end of the ovule. Filiform apparatus is rich in polysaccharides and chemottracts pollen tube towards micropyle.
The gametophyte is not an independent, free-living generation in
Adiantum
Marchantia
Pinus
Polytrichum
C.
Pinus
Unlike bryophytes and pteridophytes, in gymnosperms (e.g., Pinus, Cycas, etc.), the male and female gametophytes do not have an independent free-living existence. They remain within the sporangia retained on the sporophytes.
Wind pollination is common in
lilies
grasses
orchids
legumes
B.
grasses
Pollination by the wind (anemophily) is more common amongst abiotic pollinations. Wind pollination is quite common in grasses.
Nucellar polyembryony is reported in species of
Gossypium
Triticum
Brassica
Citrus
D.
Citrus
The occurrence of more than one embryo in a seed is referred as polyembryony. In many Citrus and mango varieties, some of the nucellar cells surrounding the embryo sac and develop into the embryos in such species each ovule contain many embryos (nucellar polyembryony).
In which one of the following pollination is autogamous?
Xenogamy
Chasmogamy
Cleistogamy
Geitonogamy
C.
Cleistogamy
Bisexual flowers which remain always closed are called the cleistogamous and such condition of flowers is called cleistogamy. In such flowers, the anthers and stigma lie close to each other. When anthers dehisce in the flowers buds, pollen grains come in contact with stigma to effect pollination. Thus, cleistogamous flowers are invariably autogamous.
In angiosperms, functional megaspore develops into
embryo sac
ovule
endosperm
pollen sac
A.
embryo sac
In angiosperms, the unit of female gametophyte (embryo sac) is functional megaspore.
Apomictic embryos in Citrus arise from
Synergids
maternal sporophytic tissue in ovule
antipodal
diploid egg
B.
maternal sporophytic tissue in ovule
Substitution of usual sexual reproduction by a form of reproduction which does not involve meiosis and syngamy is called apomixis. In Citrus, apomictic embryo arises from diploid cells. (maternal sporophytic tissue) of the ovule occurring outside the embryo sac.
Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called
xenogamy
geitonogamy
karyogamy
autogamy
B.
geitonogamy
Geitonogamy (Greek geiton = neighbour and gameiu = to marry) involves the transfer of pollen grains from a male flower to the stigma of another female flower origination on the same plant. Thus, geitonogamy operates only in monoecious plants i.e plants having male and female flowers on different places but on the same plant, e.g maize (zea mays). In animal pollinated system, thisis accomplished by pollinator visiting multiple flowers on the same plant. It is also possible within species that are wind pollinated.
Wind pollinated flowers are
small, brightly coloured, producing large number of pollen grains
small, producing large number of dry pollen grains
large, producing abundant nectar and pollen
small, producing nectar and dry pollen
B.
small, producing large number of dry pollen grains
Pollination taking place by means of wind is known as anemophily, eg, Zea mays, Cannabis Pinus, etc. Some features of wind-pollinated flowers are -
i) Non -essential Whorls such as calyx, corolla and bracts, bracteoles are not showy.
ii) The perianth lobes are undeveloped or reduced and sometimes absent.
iii) Flowers are devoid of scent and nectars.
iv) Plants produce a very large quantity of dusty pollen grains.
v) Pollen grains are dry, very small sized, non-sticky and unwettable
These features are helpful for the individuality of pollen grains.
Synapsis occurs between
a male and female gamete
mRNA and ribosomes
spindle fibres and centromere
two homologous chromosomes
D.
two homologous chromosomes
In zygotene of prophase-I, homologous chromosomes pair up. This process is called synapsis. One chromosome of the pair is from the male parent and one from the female parent.
Cotyledons and testa are edible parts of
groundnut and pomegranate
walnut and tamarind
french bean and coconut
Cashew nut and litchi
A.
groundnut and pomegranate
Cotyledons and testa are edible parts of groundnut and pomegranate respectively.
The edible part of walnut is cotyledon; tamarind-mesocarp; french bean seeds, coconut-endosperm, testa, cotyledons and embryo, cashew nut-cotyledons and fleshy pedicles and of litchi is fleshy aril.
An example of a seed with endosperm, perisperm and caruncle is
Cotton
coffee
lily
castor
D.
castor
The seeds of castor (Ricinus communis, family -Euphorbiaceae) are endospermic dicot seeds. They possess endosperm which acts at the food storgage tissue of seed. They also possess perisperm and cruncle.
Which one of the flowing pairs of plants structures has haploid number of chromosomes?
Megaspore mother cell and antipodal cells
Egg cell and antipodal cells
Nucellus and antipodal cells
Egg nucleus and secondary nucleus
B.
Egg cell and antipodal cells
In angiosperms, a single diploid megaspore mother cell matures within the ovule. Through meiosis, it gives rise to four megaspores (haploid). In most plant, only one of these megaspore divides three times by mitosis and produces eight haploid nuclei enclosed with a 7 celled embryo sac. One nucleus is located near the opening of embryo space in the middle of embryo sac and is called polar nuclei, two nuclei are contained in cells called antipodals, located at the end of the embryo sac, opposite the egg cell.
Nucellus is centrally located mass of thin-walled parenchymatous cells covered by integuments in ovule.
Unisexuality of flowers prevents
autogamy, but not geitonogamy
Both geitonogamy and xenogamy
geitonogamy, but not xenogamy
autogamy and geitonogamy
A.
autogamy, but not geitonogamy
The transfer of pollen from the anther to stigma is called pollination. Autogamy also called self-pollination involves the transfer of pollen grains on one flower to the stigma of the same flower. Self-pollination occurs only in bisexual or hermaphrodite flowers.
Geitonogamy involves the transfer of pollen grains from a male flower to the stigma of the female flower of the same plant. Thus, geitonogamy operates only in monoecious plants ie, the plants having male and female flowers on different places.
Allogamy or xenogamy knew as cross-pollination involves the transfer of pollen grains of the male flower to the stigma of the gentically different female flower. It takes place via, various agencies like wind, water, insects etc.
What does the filiform apparatus do at the entrance into ovule?
It helps in the entry of pollen tube into a synergid
It prevents entry of more than one pollen tube into the embryo sac
It brings about opening of the pollen tube
It guides pollen tube from a synergid to egg
A.
It helps in the entry of pollen tube into a synergid
In most cases, the mature embryo sac contains 7-cells and nuclei. The cells are arranged egg apparatus (two synergid cell and one egg cell,) a central cell with two nuclei and antipodal cells ( 3 in number). The synergid cells occur laterally to the egg cell. These cells are characterised by finger- like projections called filiform apparatus towards the micropylar end. Fill form apparatus is formed due to invaginations of cell wall into the protoplasm and is made up of pectocellulosic fibres evolved in the non-cellulosic sheath. Secretion of chemotactic substances for the attraction of pollen tube during fertilisation is the function of synergies. One synergid becomes degenerate during pollen entry into the embryo sac and thus, provides a way for the entry of pollen tube into the embryo sac.
Importance of day length in flowering of plants was first shown in
Lemna
tobacco
Cotton
Petunia
B.
tobacco
The phenomenon of photoperiodism was first discovered by Garner and Allard (1920, a mammoth variety of tobacco could be made to flower only by reducing the light hours with artificial darkening. On the basis of photoperiodic response to flowering, plants (tobacco), long day plant (eg, wheat, hanbane), short - long day plant (eg Campanula), long short day plants, (eg, wild kidney bean) and day neutral plants (eg, cotton).
Male gametes in angiosperms are formed by the division of
microspore
generative cell
vegetative cell
microspore mother cell
B.
generative cell
Before pollination the pollen grain cytoplasm divides in generative cell and vegetative cell. The generative cell divides to form two male gametes.
Which one of the following is surrounded by a callose wall?
Microspore mother cell
Male gamete
Egg
Pollen grain
A.
Microspore mother cell
The wall of the pollen mother cell (microspore mother cell) is deposited by callose 
Parthenocarpic tomato fruits can be produced by
Removing androecium of flowers before pollen grains are released
Treating the plants with low concentrations of gibberellic acid and auxins
Raising the plants from vernalized seeds
Treating the plants with phenylmercuric acetate
B.
Treating the plants with low concentrations of gibberellic acid and auxins
Parthenocarpy is the development of fruits without prior fertilization which results in the formation of seedless fruits. In some plant species, parthenocarpic (seedless) fruits may be produced naturally or they may be induced by treatment of the unpollinated flowers with auxin e.g. Parthenocarpic tomato fruits can be produced by treating the plants with low concentration of gibberellic acid (promotes fruit set) and auxin (completes the development process).
Removal of androecium, before pollen release, is called emasculation which is helpful in preventing unwanted poor pollination.
Vernalized seeds are the chill treated seeds for breaking dormancy.
Phenyl mercuric acetate is an antitranspirant.
Long filamentous threads protruding at the end of a young cob of maize are
anthers
styles
ovaries
hairs
B.
styles
In cob of maize, each ovary has a long silky (hairy) style, called as corn silk. Collectively these styles protrude at the end of a young cob. The grains are formed on the cob which remain covered by the leafy bracts.
Conifers differ from grasses in the
production of seeds from ovules
lack of xylem tracheids
absence of pollen tube
formation of endosperm before fertilization
D.
formation of endosperm before fertilization
The conifers (gymnosperm) differ from the endosperm before fertilization. In fact, in gymnosperms, the endosperm is formed before the fertilization, thus, it is a haploid tissue while in angiosperms, endosperm is formed after fertilization as a result of triple fusion or double fertilization, thus, it is a triploid tissue.
In both conifers and grasses seeds are produced from ovules.
Xlem tracheids are present in both conifers and grasses.
Pollen tubes are also formed in both conifers and grasses.
The arrangement of the nuclei in a normal embryo sac in the dicot plants is
2+4+2
3+2+3
2+3+3
3+3+2
B.
3+2+3
In angiosperms (dicots), the Polygonum type of embryosac is most common. In this embryosac, the arrangement of the nuclei is 3+2+3 i.e., 3 in antipodal cells, 2 as polar nuclei (which later fuse and form a diploid secondary nucleus); and 3 in egg appratus (2 in synergids and 1 in egg cell).
An enzyme that can stimulate germination of barley seeds is
α-amylase
lipase
protease
invertase
A.
α-amylase
Barely seeds are rich in carbohydrate (Starch). The starch is hydrolysed by α-amylase to monosaccharides unit at the time of germination of seeds.
A dioecious flowering plant prevents both:
Autogamy and xenogamy
Autogamy and geitonogamy
Geitonogamy and xenogamy
Cleistogamy and xenogamy
B.
Autogamy and geitonogamy
Functional megaspore in an angiosperm develops into
Ovule
Endosperm
Embryo sac
Embryo
C.
Embryo sac
Megaspore is the first cell of female gametophytic generation in angiosperm. It undergoes three successive generations of free nuclear mitosis to form 8-nucleated and 7-celled embryo sac.
Double fertilization is
Fusion of two male gametes of a pollen tube with two different eggs
Fusion of one male gamete with two polar nuclei
Syngamy and triple fusion
Fusion of two male gametes with one egg
C.
Syngamy and triple fusion
Double fertilization is a phenomenon that occurs in angiosperms only.
Syngamy + Triple fusion = Double fertilization
Pollen grains can be stored for several years in liquid nitrogen having a temperature of
–120°C
–80°C
–160°C
–196°C
D.
–196°C
Pollen grains can be stored for several years in liquid nitrogen at –196°C (Cryopreservation)
Which of the following has proved helpful in preserving pollen as fossils?
Pollenkitt
Cellulosic intine
Sporopollenin
Oil content
C.
Sporopollenin
Sporopollenin cannot be degraded by the enzyme; strong acids and alkali, therefore it is helpful in preserving pollen as fossil.
Pollenkitt – Help in insect pollination.
Cellulosic Intine – Inner sporoderm layer of pollen grain known as intine made up cellulose & pectin.
Oil content – No role is pollen preservation.
Offsets are produced by
Meiotic divisions
Mitotic divisions
Parthenogenesis
Parthenocarpy
B.
Mitotic divisions
Offset is a vegetative part of a plant, formed by mitosis.
– Meiotic divisions do not occur in somatic cells.
– Parthenogenesis is the formation of an embryo from ovum or egg without fertilisation.
– Parthenocarpy is the fruit formed without fertilisation, (generally seedless).
Winged pollen grains are present in
Mustard
Cycas
Pinus
Mango
C.
Pinus
In Pinus, winged pollen grains are present. It is extended outer exine on two lateral sides to form the wings of pollen. It is the characteristic feature, only in Pinus. Pollen grains of Mustard, Cycas & Mango are not winged shaped.
With respect to angiosperms, identify the incorrect pair from the following
antipodal - 2n
Vegetative all of male gametophyte - n
Primary endosperm nucleus-3n
Cell of nucellus of ovule -2n
A.
antipodal - 2n
Out of the given pairs in the option, the only antipodal is wrongly matched because antipodals are haploid cells (n) found within the mature embryo sac towards the chalazal end. Rest all three options are correctly matched.
Which one of the following statements is correct?
Hard outer of pollen is called intine
Sporogenous tissue is haploid
ENdothelium produces the microspores
Tapetum nourishes the developing pollen
D.
Tapetum nourishes the developing pollen
Endosperm of gymnosperms is
Haploid
Tetraploid
Diploid
None of these
A.
Haploid
The endosperm of a gymnosperm is a pre-fertilisation tissue. It is basically the female gametophyte hence it is haploid unlike triploid in angiosperm.
When pollen tube enters through micropyle, the process is called
Porogamy
Chalazogamy
Mesogarny
Apogamy
A.
Porogamy
The pollen tube may enter the ovule by following one of three routes given below:
(a) Porogamy Pollen tube enters the ovule through micropyle, e.g., most angiosperms.
(b) Mesogamy Pollen tube enters the ovule through integuments (e.g., Cucurbita) or through funiculus (e.g., Pistacia).
(c) Chalazogamy Pollen tube enters the ovule through chalazal tissues, e.g., Casuarina, Beta vulgaris, Juglens regia, etc.
Outer wall of pollen grain is made up of
Cellulose
Sporopollenin
Pectocellulose
Lignin
B.
Sporopollenin
A pollen grain contains two-layered cell wall, the outer exine and inner intine. Sporopollenin is found in the exine of pollen grains, which is the most resistant biological material known, of microbial and chemical decomposition. Due to this, pollen grains are well preserved during fossilization. Intine of pollen grain is made up of pectocellulose.
Which of the following floral parts forms pericarp after fertilization?
Nucellus
Outer integument
Ovary wall
Inner integument
C.
Ovary wall
After fertilization, the mature, ripened ovary develops into fruit. The ovary wall forms the covering of the fruit called fruit wall or pericarp. Some other post fertilization changes also occur like nucellus develops into perisperm, ovules develop into seeds, outer integument forms testa, inner integument forms tegmen, etc.
Unisexuality of flowers prevents
Autogamy, but not geitonogamy
Both geitonogamy and xenogamy
Geitonogamy, but not xenogam
Autogamy and geitonogamy
A.
Autogamy, but not geitonogamy
Rarely among angiosperms, the pollen grains influenced the endosperm. This is called as
Meta xenia
Nemec phenomenon
Xenia
Mesogamy
C.
Xenia
The direct or indirect effect of pollen is seed or fruit has been termed by Foke (1881) as Xenia. This phenomenon is seen is Zea mays alone and in limited to the endosperm part only.
When two unrelated individuals or lines are crossed, the performance of F1 hybrid in often superior to both of its parents. This phenomenon is called
Transformation
Heterosis
Splicing
Meta Morphosis
B.
Heterosis
The superiority of hybrids over either of the parent is called heterosis or hybrid.
An irregular mode of reproduction resulting in the development of an embryo without fertilization is called
(I) parthenogenesis
(II) apogamy
(III) sporophytic budding
Select the correct answer using the code given below.
Only I
Only II
II and III
I, II and III
D.
I, II and III
In parthenogenesis formation of fruit occurs without fertilisation In apogamy haploid (n) vegetative cell forms embryo without gametogenesis and fertilisation, In sporophytic budding diploid (2n) vegetative cell forms embryo from bud by vegetative reproduction Thus, all of these processes are irregular modes of reproduction.
Compare the statement I and II and choose the correct option.
Statement I In the flowering plants due to higher accumulation of auxins dormancy of lateral buds occurs.
Statement II In Maryland Mammoth (a tobacco variety) flowering occurred at a different time at different latitude due to gibberellins concentration.
Statement I is true, but II is false
Statement I is false, but II is true
Both statements are true
Both statements are false
A.
Statement I is true, but II is false
Auxin is responsible for apical dominance in apical buds, which inhibits the lateral buds to grow. Plants require a certain day length to flower. This relative length of day and night needed for flowering is called as photoperiod. The effect of photoperiod or daily duration of light hours and dark periods on the growth and development of plants, especially flowering, is called photoperiodism. This phenomenon was first discovered by Garner and Allard (1920, 1922) on Maryland Mammoth variety of tobacco. They observed that the Maryland Mammoth could be made to flower only by reducing the light hours with artificial darkening. It could be made to remain vegetative in winter by providing extra light.
Which one of the given pollination technique/adaptation is different than others?
Herkogamy
Geitonogamy
Dichogamy
Heterostyly
B.
Geitonogamy
Geitonogamy is a technique of self-pollination, in which pollen of one flower is deposited on the stigma of another flower of the same plant. While others are mechanisms adopted by bisexual flowers to avoid self-pollination and promote Cross-pollination.
• Dichogamy The condition where the maturing time of anther and stigma is different. Anther matures first, i.e.protandry, stigma matures first, i.e. protogyny.
• Herkogamy Includes mechanical barrier in flower to ensure cross-pollination.
• Heterostyle The height of stigma and Anther is different to avoid self-pollination.
Pappus helps in the dispersal of pollen in
Asteraceae
Brassicaceae
Malvaceae
Solanaceae
A.
Asteraceae
Pappus are modified bracts of Asteraceae family.These hairy structures help in dispersal of pollen by
wind.
The one advantage of cleistogamy is
It leads to greater genetic diversity
Seed dispersal is more efficient and wide spread
seed set is not dependent on pollinators
Each visit of pollinator results in the transfer of hundreds of pollen grains
C.
seed set is not dependent on pollinators
Cleistogamous flowers do not open so, they self-pollinate and thus, do not depend on pollinators.
Double fertilization occurs in
Riccia
Pteridium
Cycas
Capsella
D.
Capsella
Double fertilization is the characteristic feature of angiosperms, e.g, Capsella. It includes fusion of one male gamete with egg and second male gamete with a secondary nucleus (this forms endosperm).
In gymnosperms, the pollen chamber represents
A cell in the pollen grain in which the sperms are formed
A cavity in the ovule in which pollen grains are stored after pollination
An opening in the megagametophyte through which the pollen tube approaches the egg
The microsporangium in which pollen grains develop
B.
A cavity in the ovule in which pollen grains are stored after pollination
In gymnosperms, the pollen chamber is a cavity in the ovule in which pollen grains are stored after pollination.
Ubisch bodies are present in
pollen tube
pollen grain
microspore
tapetum
D.
tapetum
Tapetum is the innermost layer of another wall which surrounds the sporogenous tissue. These cells are nutritive in function. also, ubisch bodies are present that helps in the formation of microspore wall or exine of pollen grains.
Pollen grain (microspore) is a round haploid structure from which gametophyte is developed.
Pollen tube helps in carrying male gametes to female gametes for fertilisation.
In Cycas, pollination takes place in
3- celled stage
4- celled stage
2- celled stage
1- celled stage
A.
3- celled stage
| Plant | Pollination takes place in |
| Cycas | 3- celled stage |
| Pinus | 4 to 5 celled stage |
| Angiosperm | 2 to 3 celled stage |
In Pinus, male cone bears a large number of
ligules
anthers
micro- sporophylls
mega- sporophylls
C.
micro- sporophylls
Micro-sporophylls or mega- sporophylls are the leaf like structures on which microsporangia and megasporangia are borne on the same plant of Pinus.
(a) Male cones (microstrobili)- are small
(b) Female cones (ovulate strobili)- are large
Each male cone consists of an elongated axis containing number of micro- sporophylls. Underside of same develops 2 microsporangia and gets filled with microspores (pollen grains).
Anther or microsporangium is the male reproductive structure of angiosperm.
Ligule, is a tongue- like membranous outgrowth, present on upper surface, near the base of the microphyllous leaf in pteridophytes.
Cleavage polyembryony occurs in
Pinus
Mini Cycas
Cycas
Ephedra
A.
Pinus
Polyembryony is common in gymnosperms. It is because more than one archegonia are fertilized and more than one zygotes are formed. All develop into embryos but only one of them succeeds in developing complete embryo.
In Cycas, pollination takes place in
3- celled stage
4- celled stage
2- celled stage
1- celled stage
A.
3- celled stage
in Cycas, pollination takes place in 3- celled stage, ie, pollen grain divides to form three cells, which are
(i) Prothalial cell
(ii) Generative cell
(iii) Tube cell
Nucellus forms which of the following part of fruit?
Seed coat
Perisperm
Seed
Raphe
B.
Perisperm
The post fertilization changes in the seeds are as follows-
(i) Ovule - Seed
(ii) Ovary - Fruit
(iii) Nucellus - Perisperm (a nutritive tissue)
(iv) Integument - Seed coat
Growth of pollen tube towards embryo sac is
geotropism
thigmotaxis
chemotaxis
All of these
C.
chemotaxis
Chemotaxis is a locomotory movement in response to presence of chemicals, eg. growth of pollen tube towards egg.
Perisperm is
degenerate part of synergids
peripheral part of endosperm
degenerate part of secondary nucleus
remnant of nucellus
D.
remnant of nucellus
Perisperm is the remnant of nucellus. It is found in Piperaceae and Scitaminaceae. It is formed when the nucellus is not completely used up and is present in the form of a thin layer in the seed enclosing the embryo and the endosperm
An orthotropus ovule is one in which micropyle and chalaza are
in straight line of funiculus
parallel of funiculus
at right angles to funiculus
oblique to funiculus
A.
in straight line of funiculus
Orthotropous ovule is also called atropous. In this type of ovule the micropyle, chalaza and funicle lie in one straight line, e.g., Polygonaceae, Piperaceae etc.
In a type of apomixis known as adventive embryony, embryos develop directly from the
nucellus or integuments
synergids or antipodals in an embryo sac
accessory embryo sacs in the ovule
zygote
A.
nucellus or integuments
Apomixis does not involve gamete formation and fertilization is found in amphimixis. Adventive embryo formation is a type of apomixis in which embryos are formed from diploid integumental or nucellar cells.
Through which cell of the embryo sac, does the pollen tube enter the embryo sac?
Egg cell
Central cell
Persistant synergid
Degenerated synergid
D.
Degenerated synergid
Egg apparatus is present towards the micropylar end of an ovule. It has two lateral synergid cells and one centrally located egg cell. During entry of pollen tube within the ovule, synergid cells become disintegrate and provide path for entry of pollen tube within the chamber of embryo sac.
Which one of the following represents an ovule, where the embryo sac becomes horse-shoe shaped and the funiculus and micropyle are close to each other?
Circinotropous
Anatropous
Amphitropous
Atropous
C.
Amphitropous
In an amphitropous ovule, the embryo sac becomes horse- shoe shaped and the funiculus and micropyle are close to each other. It is found in Alismaceae, Butamaceae families.
Circinotropous ovule- The nucellus and the axis are in the same line in the beginning but due to rapid growth on one side, the ovule becomes anatropous.
Anatropous ovule is a completely inverted ovule turned back 180 on its stalk.
Double fertilisation was discovered by
Nawaschin
Starsburger
Emerson
None of the above
A.
Nawaschin
The two gametes released by the pollen tube move in opposite direction most probably the streaming currents of cytoplasm. One gamete fuses with egg called fertilisation and second fuses with two polar nuclei called triple fusion i.e. fertilisation and triple fusion jointly called double fertilisation. It was first observed by Nawaschin (1848) in Lilium and Fritillaria. This phenomenon is unique to angiosperm.
Among plants 'pheromones' are secreted by the cells of the following plants for given function
all plants for growth and development
Yeast for facilitating mating
all fungi for sexual reproduction
Rhizopus for formation of zygospore
B.
Yeast for facilitating mating
Pheromone is a substance secreted to outside by an individual and received by a second individual of the same specie in which it induces a specific reaction e.g. fusion of two yeast cells during sexual reproduction.
If the pollen tube enters the ovule through funiculus, the phenomenon is known as
porogamy
chalazogamy
mesogamy
heterogamy
C.
mesogamy
In porogamy the pollen tube enters the ovule through micropyle, in chalazogamy pollen tube enters through chalaza and in mesogamy pollen tube enters through funiculus.
Which of the following is the most resistant material in pollen grain
Sporopollenin
Intine
Exine
Certicle
A.
Sporopollenin
Sporopollenin is most resistant chemical substance in pollen grains wall.
For the formation of tetrasporic embryosac, how many megaspore mother cells are required?
1
2
3
4
D.
4
Tetrasporic is the development when all the four megaspore nuclei takes part in the formation of the female gaemtophyte (embryo sac). In tetrasporic embryo sac, meiosis is not accompained by wall formation.
Double fertilization means
fusion of nucleus of male gamete with the egg nucleus
fusion of two polar nuclei
fusion of sperm nucleus with secondary nucleus
fusion of one sperm nucleus with nucleus and fusion of other sperm nucleus with secondary nucleus
D.
fusion of one sperm nucleus with nucleus and fusion of other sperm nucleus with secondary nucleus
Double fertilization was first observed by Nawaschin (1892) in Lilium and Fritillaria and confirmed by Grignard. It is characteristic of angiosperms. In double fertilization first fertilization is normal and second, as it involves three nuclei is known as triple fusion.
If there are 4 microspore mother cells in an anther, what will be the number of pollen grains?
4
8
12
16
D.
16
Each microspore mother cell divides meiotically to form 4 pollen grains (4 4 = 16).
After double fertilisation, a mature ovule has
I diploid and I haploid cell
1 diploid and I triploid cell
2 haploid and I triploid cell
1 haploid and I triploid cell
B.
1 diploid and I triploid cell
Double fertilisation is found only in angiosperms. In this group of plants, the pollen tube on entering the embryo sac bursts open in one of the two synergids to release the two male gametes.
One male gamete fuses with the egg or oosphere to form a diploid zygote or oospore. It is called generative fertilisation.
The second male gamete descends down and fuses with the diploid secondary nucleus of the central cell to form a triploid primary endosperm cell. It is known as vegetative fertilisation.
Thus, after double fertilisation, a mature angiospermous ovule contains one diploid cell (zygote) and one triploid cell (primary endosperm cell). The haploid cells of the ovule such as antipodals and synergids degenerate after fertilisation
Identify the parts labelled A, B, C and D in the given figure and select the correct option.
A- Scutellum, B- Epiblast, C- Coleoptile, D- Coleorhiza
A- Scutellum, B- Coleorhiza, C- Coleoptile, D- Epiblast
A- Scutellum, B- Coleoptile, C- Coleorhiza, D- Epiblast
A- Epiblast, B- Coleoptile, C- Coleorhiza, D- Scutellum
C.
A- Scutellum, B- Coleoptile, C- Coleorhiza, D- Epiblast
Scutellum is a thin cotyledon in monocots found in the members of the grass family. It is situated towards one side of the embryonal axis.
Coleoptile is a sheath protecting a young shoot tip in a grass or cereal.
Coleorhiza is a sheath protecting the root of a germinating grass or cereal grain.
Epiblast is a flap- like projection of the coleorhiza, inserted opposite the scutellum.
Match column I with column II and select the correct option from the given codes.
| Column I | Column II |
| A. Parthenocarpy | (i) Seed formation without fertilisation |
| B. Polyembryony | (ii) More than one embryo in same seed |
| C. Apomixis | (iii) Seedless fruits without fertilisation |
| D. Somatic embryogenesis | (iv) Embryo develops from a somatic cell |
A- (iv), B- (ii), C- (iii), D- (i)
A- (iii), B- (ii), C- (i), D- (iv)
A- (i), B- (iv), C- (iii), D- (ii)
A- (ii), B- (iii), C- (i), D- (iv)
B.
A- (iii), B- (ii), C- (i), D- (iv)
Parthenocarpy is the development of a fruit without prior fertilization.
Polyembryony is the formation of more than one embryo from a single fertilized ovum or in a single seed.
Apomixis is the asexual reproduction in plants, in particular agamospermy.
Somatic embryogenesis is an artificial process in which a plant or embryo is derived from a single somatic cell.
What is the correct sequence of the formation of female gametophyte in angiosperms
Nucellus, megapore tetrad, megaspore mother cell, megaspore, female gametophyte
Megaspore tetrad, nucellus, megaspore mother cell, megaspore, female gametophyte
Nucellus, megaspore mother cell, megaspore tetrad, megaspore, female gametophyte
Megaspore mother cell, megaspore tetrad, megaspore, nucellus, female gametophyte
C.
Nucellus, megaspore mother cell, megaspore tetrad, megaspore, female gametophyte
In angiosperms, the body of the ovule consists of a mass of parenchymatous cells called nucellus. In the hypodermal region of nucellus towards the micropylar end develops a primary archesporial cell, which by further divisions forms a diploid megaspore mother cell. The latter undergoes meiosis to form megaspore tetrad. Usually the chalazal megaspore remains functional while the other three degenerate. The functional megaspore is the first cell of female gametophyte (embryo sac).
Primary endosperm nucleus (PEN) is formed by the fusion of
2 polar nuclei + I synergid cell nucleus
I polar nucleus + I antipodal cell nucleus + I synergid cell nucleus
2 polar nuclei+ I male gamete nucleus
2 antipodal cell nuclei + I male gamete nucleus
C.
2 polar nuclei+ I male gamete nucleus
During the event of double fertilisation in angiosperms, the second male gamete fuses with the two haploid polar nuclei or diploid secondary nucleus of the central cell to form a triploid primary endosperm nucleus (PEN). This second fertilisation is called vegetative fertilisation.
Tetradynamous condition is found in
Hibiscus rosa-sinesis
Ocimum sanctum
Helianthus annuus
Brassica campestris
D.
Brassica campestris
In tetradynamous condition there is 4 + 2 arrangement of stamens i.e., out of six stamens, 4 are long and 2 are short. It is a characterstic feature of members of family Brassicaceae.
Apomixis is
formation of seeds by fusion of gametes
formation of seeds without syngamy and meiosis
formation of seeds with syngamy but no meiosis
none of the above
B.
formation of seeds without syngamy and meiosis
Apomixis (Gk. apo-without, mixismixing) is a mode of reproduction which does not involve formation of zygote through gametic fusion. It is, therefore, akin to asexual reproduction. In plants apomixis commonly mimics sexual reproduction but produces seeds without fertilisation, e.g., some species of Asteraceae and grasses.
A- Connective tissue, B- Pollen grain, C- Endothecium
A- Endothecium, B- Connective tissue, C- Pollen grains
A- Pollen grains, B- Connective tissue, C- Endothecium
A- Endothecium, B- Pollen grains, C- Connective tissue
A.
A- Connective tissue, B- Pollen grain, C- Endothecium
Anther consists of two lobes, each with two elongated microsporangia or pollen sacs. The anther lobes are fused together by the connective tissue.
Assertion : Endothecium layer of anther wall plays an important role in dehiscence of anther.
Reason : The presence of fibrous bands and differential expansion of inner and outer tangential walls of endothecial cells cause dehiscence of anther.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
A.
If both assertion and reason are true and reason is the correct explanation of assertion
Dehiscence is the splitting along a built- in line of weakness in a plant structure in order to release its contents and is among fruits, anthers and sporangia.
How many haploid nuclei are present in a mature pollen grain
One
Two
Three
Four
B.
Two
Mature pollen grain carries two haploid nuclei which moves into the cytoplasm of the synergid.
One of the male gametes moves towards the egg cell and fuses with its nucleus thus completing the syngamy. This results in the formation of a diploid cell, the zygote. The other male gamete moves towards the two polar nuclei located in the central cell and fuses with them to produce a triploid primary endosperm nucleus (PEN)
Cotton fibres mainly contains
cellulose
glycogen
protein
lipid
A.
cellulose
The cotton fibres represent epidermal prolongations of seed coat cells. A raw cotton fibre, on average, gives the following values on analysis:
Cellulose, 94%, Protein - 1.3%, Pectic substances - 0.9%, Ash- 1.2%, Wax - 0.6%, Sugars -0.3% and traces of pigments and mineral matter.
Upon fertilization, what structure develops from carpel?
Testa
Tegmen
Pericarp
Perisperm
C.
Pericarp
Ripened ovary or fertilized ovary is called fruit. The wall of the ovary forms fleshy or dry fruit wall known as pericarp. It means that the pericarp is developed from pistil or carpel.
Testa is the hard external coating or integument of a seed.
Tegmen is a covering or integument, usually referring to a thin layer or membrane in an organism.
Perisperm in some seeds is a mass of nutritive material outside the embryo sac.
Even after killing the generative cell with a laser beam, the pollen grain of a flowering plant germinates and produces normal pollen tube because
laser beam stimulates pollen germination and pollen tube growth
the laser beam does not damage the region from which pollen tube emerges
the contents of killed generative cell permits germination and pollen tube growth
the vegetative cell has not been damaged
D.
the vegetative cell has not been damaged
During the post-pollination development, germination of pollen grain takes place. The pollen grain absorbs water and nutrients on the stigma from the stigmatic secretion through its germ pores. The tube or vegetative cell enlarges and comes out of the pollen grain through one of the germ pores or germinal furrows to form a pollen tube. Generative cell does not produces pollen tube instead it passes into the pollen tube and divides into 2 male gametes. Thus even after killing the generative cell with a laser beam, the pollen grain produces normal pollen tube because the vegetative cell has not been damaged.
Assertion : Protandry and protogyny ensures cross fertilization.
Reason : Cross fertilization introduces variation in progeny.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
B.
If both assertion and reason are true but reason is not the correct explanation of assertion
In some lower animals, the organs of both the sexes are found in the same individual. Hence, they are called bisexual or monoecious animals or hermaphrodites. In these animals, testes and ovaries do not mature simultaneously.
For example in earthworm, testes mature earlier, while in others, e.g., sea-squirt, ovaries mature earlier. These conditions are respectively called protandry and protogyny. They ensure cross fertilization.
Cross fertilization is a process in which gametes derived from different individuals are united to form zygote. It involves the mixing of two different genetic materials. This is better than self-fertilization as it introduces variation by combining traits of two individuals.
Assertion : Pollen mother cells (PMCs) are the first male gametophytic cells.
Reason : Each PMC gives rise to two pollens.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
D.
If both assertion and reason are false
Primary sporogenous cell gives rise to microspore mother cells or pollen mother cells (PMCs). They are sporophytic in nature i.e., diploid. These cells undergo meiosis (reduction division) which gives rise to 4 microspores or pollens and this formation of microspores or pollens is called microsporogenesis. Microspores represent the beginning of the gametophytic phase and they are haploid in nature.
Which one of the following pairs of plant structures has haploid number of chromosomes
Nucellus and antipodal cells
Egg nucleus and secondary nucleus
Megaspore mother cell and antipodal cells
Egg cell and antipodal cells
D.
Egg cell and antipodal cells
The egg cell is one of the haploid cell of egg apparatus present in the micropylar end of embryo sac in seeded plants. It is also cal led oosphere and represents the single female gamete of the embryo sac. Antipodal cells are the haploid cells, usually three in number, present in embryo sac at the opposite end of micropyle. Their function is unknown and at fertilization, they may disintegrate or multiply and enlarge.
Assertion : Emasculation prevents self- pollination in flowers.
Reason : Emasculation is the removal of anthers from a bisexual flower.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
A.
If both assertion and reason are true and reason is the correct explanation of assertion
Emasculation is the removal of the anthers of a flower in order to prevent self- pollination or the undesirable pollination of neighbouring plants. It is mainly done in plants, by removing the stamens of a flower before they achieve reproductive maturity. It is done in bisexual flowers to prevent self- pollination.
Assertion: Maize is an albuminous seed.
Reason: Endosperm is completely absorbed by its growing embryo
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
C.
If assertion is true but reason is false
Any seed which contains endosperm or perisperm at maturity is called albuminous or endospermic seed i.e., food reserve of the seed is stored in endosperm or perisperm, e.g. rubber, coconut, castor bean, maize and other cereals. Seed that does not have endosperm at maturity and in which cotyledons absorb food reserve from endosperm during development and act as storage organs is called exalbuminous or nonendospermic seed, e.g., mustard, groundnut, bean, pea etc.
Apomixis is
formation of seeds by fusion of gametes
formation of seeds without syngamy and meiosis
formation of seeds with syngamy but no meiosis
none of the above
B.
formation of seeds without syngamy and meiosis
Apomixis in flowering plants is defined as the asexual formation of a seed from the maternal tissues of the ovule, avoiding the processes of meiosis and fertilization leading to embryo development.
In some plants, normal sexual reproduction has no meiosis and syngamy. It is of two types- vegetative reproduction and agamospermy. In vegetative reproduction plants develop from parts other than seeds. In agamospermy, plants produce seeds as means of propagation by abnormal method.
Assertion: Nuclear endosperm is formed by subsequent nuclear division without wall formation.
Reason: Coconut is an example of such endosperm, where the endosperm remains nuclear throughout the development of the fruit
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
C.
If assertion is true but reason is false
In nuclear endosperm, first and further divisions of primary endosperm nucleus arc not followed by cytokinesis or wall formation and thus these free nuclear divisions lead to formation of a large number of free nuclei in embryo sac. At maturity, centripetal wall formation may occur to make the tissue partly cellular. Endosperm of coconut is unique in sense that it is both nuclear and cellular. Here the primary endosperm nucleus undergoes a number of free nuclear divisions. When the fruit is about 50 mm long the embryo sac remains filled with a watery fluid or milk containing free nuclei and fine cytoplasmic particles. At a later stage when the fruit becomes about 100mm in length the liquid shows in addition to free nuclei, several cells each enclosing variable number of nuclei. Thus coconut has multicellular endosperm (called coconut meat) in the outer part and free
Assertion : Vegetable oils are fats which are present in plant cells in soluble form.
Reason : Vegetable oils occur only in cells of embryo.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
D.
If both assertion and reason are false
Vegetable oils and fats are located in the form of small insoluble droplets within the plant cells. They are commonly found in seeds, especially in the endosperm and cotyledons. In most of the cereals, however, the fat occurs almost exclusively in the embryo. Olive and palm oils are two important examples that are obtained from the fleshy pericarp of the fruit. Less frequently, oils and fats are extracted from the roots, stems and foliage.
Plants of which one of the following groups of genera arc pollinated by the same agency
Triticum, Cocos, Mangifera
Ficus, Kigelia, Casuarina
Salvia, Morus, Euphorbia
Bombax, Butea, Bauhinia
D.
Bombax, Butea, Bauhinia
Pollination by birds is called ornithophily, eg. humming birds, honey eaters, sunbirds etc. arc sensitive to colours and have powerful vision. Plants like Bombax, Butea, etc are ornithophilous plants. There flowers are characterised by tubular, cup shaped corolla. bright colour to attract insect, excess of nectar and pollens. They are generally odourless. Bauhinia is mostly visited by hummingbirds and their propagules are dispersed by birds
In which one of the following would you expect to find glyoxysomes?
Endosperm of wheat
Endosperm of castor
Palisade cells in leaf
Root hairs
B.
Endosperm of castor
Glyoxysomes are enzymes which play a critical role in lipid metabolism in seedlings. Hence, they are supposed to be present in endosperm of castor as endosperm of wheat will posses starch.
Double fertilization involves
fertilization of the egg by two male gametes
fertilization of two eggs in the same embryo sac by two sperms brought by one pollen tube
fertilization of the egg and the central cell by two sperms brought by different pollen tubes
fertilization of the egg and the central cell by two sperms brought by the same pollen tube.
D.
fertilization of the egg and the central cell by two sperms brought by the same pollen tube.
Double fertilization is a complex fertilization mechanism of flowering plants ie, angiosperms. It involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). One male nucleus fertilizes the egg nucleus and the other male nucleus fertilizes the central cell (polar nuclei). First fertilization result in zygote where as second fertilization results in the formation of endosperm.
The pollen tube usually enters the embryo sac
through one of the synergids
by directly penetrating the egg
between one synergid and central cell
by knocking off the antipodal cells.
A.
through one of the synergids
The pollen tube arrives in the micropyle of the integument of the ovule, and enters the embryo sac.
The synergids of the embryo sac literally put their energies together to burst the end of the pollen tube. Meanwhile, the generative cell has followed the pathway digested by the tube cell. Along the way it has divided to produce two sperm cells. The two sperm cells exit the pollen tube through the burst end.
One sperm cell unites with the egg. This process is called syngamy (union of gametes) or [gag] fertilization. I much prefer syngamy to fertilization (see below). The product of the union of egg and sperm is called a zygote, and it has two sets of master plans, one from each gamete. The zygote will divide and grow and differentiate to become a new embryonic plant with root, stem, and leaf. Ultimately it will become an adult plant.
Assertion: Insects visit flowers to gather honey.
Reason: Attraction of flowers prevents the insects from damaging other parts of the plant.
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
If Assertion is true but Reason is false
If both Assertion and Reason are false.
D.
If both Assertion and Reason are false.
Insects collect nectar from the flowers. The attraction of flower in plants is not to diverge the insect from damaging other part, but to bring about pollination (i.e. transfer of pollen to the stigma). The pollen grains in insect pollinated flowers are either sticky or provided with spinous outgrowths. The stigma is also sticky. Insect often visiting these flower for nectar and bring about pollination inevidently.
Pollen grains are able to withstand extremes of temperature and dessication because their exine is composed of
cutin
suberin
sporopollenin
callose
C.
sporopollenin
Exine is outer layer of pollen grain which is acetolysis resistant layer. It is also resistant to physical and biological degradation. Because of this property of exine, pollen grains are found well preserved for long periods in fossil deposits.
Cutin is a waxy repellant substance in the cuticle of plants, consisting of higly polymerized esters of fatty acids.
Suberin is an inert impermeable waxy substance present in the cell walls of corky tissues.
Callose is a plant polysaccharide. It plays an important in plant development.
Assertion: Coconut tree is distributed in coastal areas over a large part of the world.
Reason: Coconut fruit can float and gel dispersed over thousands of kilometers before losing viability.
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
If Assertion is true but Reason is false
If both Assertion and Reason are false.
A.
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
Coconut requires the hot and wet climate hence it is grown in coastal areas. It is widely grown in coastal and deltic regions of tropical and subtropical countries. Coconut fruit shows hydrochory i.e. the dispersal takes place through water medium. Being the inhabitant of coastal area the fruit is so adapted that it can float and get dispersed over thousands of kilometers before losing viability.
When the pollen tube enters through the micropyle, it is termed as
chalazogamy
mesogamy
porogamy
none of these
C.
porogamy
The process of entry of pollen tube into ovule through micropyle is called porogamy and is most common in angiosperms.
For self pollination, flower must be
unisexual
bisexual
monosexual
asexual
B.
bisexual
Self-pollination is when pollen from the same plant arrives at the stigma of a flower (in flowering plants) or at the ovule (in gymnosperms).
Assertion : Many visitors to the hills suffer from skin and respiratory allergy problem.
Reason : Conifer trees produce a large quantity of wind-borne pollen grains.
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
If Assertion is true statement but Reason is false
If both Assertion and Reason are false statements
B.
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
Some trees of hill like oak, ash, elm, hickory, pecan and mountain cedar produce allergic pollen grains which cause allergy to people. Signs and Symptoms of pollen allergy are
(i) sneezing
(ii) itching eyes, nose and throat
(iii) dark circles under the eyes caused by restricted blood flow near the sinuses
(iv) watering eyes
(v) conjunctivitis
Conifer trees produce a large quantity of wind borne pollen grains because many pollen grains are destroyed in the process of pollination done by wind.
The plant part which consists of two generations, one within the other, is
genninated pollen grain
embryo
unfertilized ovule
seed
D.
seed
Seed develops from an ovule (consisting integument and nucellus) or megasporangium. Parts of ovule develop a haploid megaspore which grow into haploid female gametophyte. This female gametophyte develops an egg or oospore. The latter is fertilized by a male gamete and develops into a zygote (2n). The zygote develops into an embryo or new sporophyte. The embryo (2n) is surrounded by the female gametophyte (n), the latter by seed coat (2n). In this way, seed contains three generations locked one within another. Of these, two generations occur within embryo.
Dispersal of fruits in Opium (poppy) occur through shaking by wind by
explosive mechanism
parachute mechanism
censer mechanism
jacular mechanism
C.
censer mechanism
In certain fruits the seeds are discharged through small openings on the fruits. The outlets are so narrow that only a few seeds can escape at a time.
The capitulum of sunflower, in which the seeds are heavy and not provided with pappus, shows a censer mechanism in the restricted escape of seeds when it is swung by wind.
The formation of gametophyte, from sporophyte, without spore formation or without meiosis is known as :
apospory
apogamy
parthenogenesis
none of these
A.
apospory
Apospory is the development of gametophyte from a cell of the sporophyte without the intervention of spore. The structure taking part in apospory may be single cell of gametophytic nature, a rhizoid or a gametophyte bearing sex organ or of sporophytic in nature.
Apogamy is a type of plant reproduction in which sporophyte (diploid phase) is produced from the gametophyte (haploid phase) without fertilization. It occurs in some type of ferns.
Parthenogensis is a type of reproduction from an ovum without fertilization. It can operate on either a haploid or a diploid cell.
Anemophillous flowers have :
sessile stigma
small and smooth stigma
coloured flower
large and feathery stigma
D.
large and feathery stigma
In anemophillous flowers, pollination is carried out by wind. The plants pollinated in this manner are grasses, which have insignificant unscented flowers with large, often feathery stigma.
Which of the following is ideal for studying meiosis?
Gamete
Pollen
Microsporangium
Root
C.
Microsporangium
The microsporangium contains microspore mother cells, which undergo meiosis to form microspores. Gamete and pollen are haploid in nature. Pollen (microspore) is the first cell of male gametophyte generation.
To which of the following flower 'synandrous' condition is found?
Sunflower (Helianthus sp)
Gourd (Cucurbita sp)
Pea (Pisum sativum)
Lemon (Citrus sp)
B.
Gourd (Cucurbita sp)
Synandrous is the fusion of stamens in which stamens are united through out their whole length, eg, members of family- Cucurbitaceae.
Study of pollen grain is called
Ethmology
Palynology
Palaeobotany
-taxonomy
B.
Palynology
Palynology is the study of pollen grains and other spores, specially found in archaeological or geological deposits.
Etymology is the study of origin of words and the way in which their meanings have changes throughout history.
Palaeobotany is the study of fossils.
- taxonomy or Encyclopaedic taxonomy is based on all the information or data available about plants.
Scientific name of sunflower is
Hibiscus rosa-sinensis
Solanum nigrum
Oryza sativa
Helianthus annuus
D.
Helianthus annuus
Ornithophily refers to the pollination by which of the following
insects
birds
snails
air
B.
birds
Ornithophily or bird pollination is the pollination of flowering plants by birds. This coevolutionary association is derived from insect pollination (entomophily) and is particularly well developed in some parts of the world, especially in the tropics and on some island chains.
Exine of pollen grain is made up o
pectocellulose
lignocellulose
sporopollenin
pollen kit
C.
sporopollenin
Pollen grains are spherical in shape. They are 25-50 micrometres in diameter. It has a prominent two-layered wall. The hard outer layer called the exine is made up of
sporopollenin. It can withstand high temperatures and strong acids and alkali. Pollen grains are well preserved as fossils because of the presence of sporopollenin. Pollen grain exine has prominent apertures called germ pores, where sporopollenin is absent. The inner wall of the pollen grain, intine is a thin and continuous layer made up of cellulose and pectin.
Seedless banana is
parthenocarpic fruit
multiple fruit
drupe fruit
true fruit
A.
parthenocarpic fruit
Parthenocarpy is a natural phenomenon whereby fruits form without being fertilized by pollen.
Ovule integument gets transformed into
seed
fruit wall
seed coat
cotyledons
C.
seed coat
Ovule integument gets transformed into seed coat, outer wall becomes testa and the inner wall becomes tegmen.
Sporopollenin is chemically
homopolysaccharide
fatty substance
protein
heteropolysaccharide
B.
fatty substance
Sporopollenin is biologically most resistant organic material (fatty substance) found in the exine (outer wall) of spores and pollen grains. It consists of complex polymers with an emperical formula (C92H142O36) formed by oxidative polymerization of carotenoids and their esters.
If you want to develop hybrid seeds within a bisexual flower, the following part needs to be removed from the same flower
stigma
ovary
anther
oviduct
C.
anther
Emasculation is the removal of stamens or anthers of a bisexual flower without affecting in anyway the female reproductive organs. It is done to prevent self-fertilization.
Xenogamy is essentially a type of
cleistogamy
allogamy
autogamy
homogamy
B.
allogamy
Xenogamy is true cross-pollination, i.e., allogamy which involves the transfer of pollen grains from the anther of one plant to the stigma of another, genetically dissimilar plant.
Cleistogamy is a type of automatic self-pollination of certain plants that can propagate by using non-opening, self-pollinating flowers.
Autogamy or self-fertilization, is the fusion of two gametes that come from one individual. It is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants.
Homogamy is a state in which the flowers of a plant are all of one type either hermaphrodite or of the same sex.
Megasporangium is equivalent to
embryo sac
fruit
nucellus
ovule
D.
ovule
An ovule or megasporangium generally has a single embryo sac formed from a megaspore through reduction division. It is a small structure attached to the placenta by means of a stalk called funicle.
Ovule Megaspore Mother Cell (MMC) by meiosis Megaspore
Each has one or two protective envelopes called integuments. Nucellus is a mass of cells enclosed with the integuments. Fruits develop from the ovary of flower, other floral parts degenerate and fall off.
Seed coat is not thin, membranous in
maize
coconut
groundnut
gram
B.
coconut
The seed coat develops from the maternal tissue, the integuments, originally surrounding the ovule. The seed coat in the mature seed can be a paper-thin layer (e.g. peanut) or something more substantial (e.g. thick and hard in honey locust and coconut), or fleshy as in the sarcotesta of pomegranate. Therefore, it is thick in coconut seed and thin, membranous in groundnut, gram and maize seeds.
Which one of the following statement is correct?
Hard outer layer of pollen is called intine
Sporogenous tissue is haploid
Endothecium produces the microspores
Tapetum nourishes the developing pollen
D.
Tapetum nourishes the developing pollen
Tapetum is the innermost layer of microsporangium. It nourishes the pollen grains. The inner wall of pollen grain is called intine. Endothecium is the wall around the microsporangium, which provide protection and help in dehiscence of anther to release the pollen. Sporogenous tissue is diploid. It undergoes meiotic division to form microspore tetrads.
Advantage of cleistogamy is
higher genetic variability
more vigorous offspring
no dependence on pollinators
vivipary
C.
no dependence on pollinators
In cleistogamous flowers, anthers and stigma lie close to each other. When anthers dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, these flowers produce assured seed set even in the absence of pollinators.
The higher genetic variability and more vigorous offsprings are produced to variations obtained by sexual reproduction. Vivipary relates to the birth of young babies from mammals.
Monoecious plant of Chara shows occurrence of
antheridiophore and archegoniophore on the same plant
stamen and carpel on the same plant
upper antheridium and lower oogonium on the same plant
upper oogonium and lower antheridium on the same plant
D.
upper oogonium and lower antheridium on the same plant
Monoeciuous plants have both male and female flowers. It has two types of flowers that develop at different parts of the plant. It is also known as homothallic condition. In Chara or green algae, it is used to denote upper oogonium and lower antheridium on the same plant. The organisms, which possess both the reproductive organs are called bisexual. Unisexual condition represents both male or female organs in same organism.
Perisperm differs from endosperm in
being a haploid tissue
having no reserve food
being a diploid tissue
its formation by fusion of secondary nucleus with several sperms
C.
being a diploid tissue
Perisperm is a nutritive tissue of a seed derived from the nucellus and deposited external to the embryo sac. It is remnants of nucellus which is diploid (2n) but endosperm is triploid (3n). It occurs in the seeds of Black perpper, coffee, castor etc. Endosperm is the food laden tissue which is meant for nourishing the embryo in seed plants. In angiosperms the endosperm is formed as a result of vegetative fertilization, triple fusion or fusion of a male gamete with diploid secondary nucleus of the central cell.
Cross-pollination through insect agent is called
anthropophily
malacophily
entemophily
ornithophily
C.
entemophily
Pollination is the phenomenon of transfer of pollen grains from the anther of the stamen to the stigma of the carpel/pistil of a flower. Entomophily is a type of pollination that takes place with the help of insects. Anthropophily is the pollination by humans (often artificial pollination using hybridisation techniques, etc). Malcophily is the pollination by snails. Ornithophily or bird pollination is the pollination of flowering plants by birds.
Cleistogamous flowers are
bisexual flowers which remain opened
bisexual flowers which remain closed
open female flower
open male flower
B.
bisexual flowers which remain closed
Cleistogamous flowers are inconspicuous, a petalous flowers. Cleistogamy or automatic self-pollination describes the trait of certain plants that are bisexual and remain closed throughout their life. They propagate by using non-opening self-pollinating flowers, i.e., they fertilise themselves by using stigma and pollen of same flower e.g., peas, peanuts, beans, etc.
Emasculation ensures cross-pollination in
staminate flower
bisexual flower
neuter flower
pistillate flower
B.
bisexual flower
Emasculation is the technique in plant breeding for crop improvement programmes. It involves the removal of anthers from bisexual flowers buds of the female parents before the anther dehisces by means of a pair of forceps in order to avoid self or cross-pollination. However, if a female parent produces unisexual flowers there is no requirement for emasculation.
Malacophily is the pollination by
insects
birds
snails
mammals
C.
snails
Malacophily is the pollination of plants by snails.
Pollination in plants by insects is called entomophily.
Pollination in plants by birds is called omithophily.
Pollination in plants by mammals is called zoophily.
Endosperm nucleus is
n
2n
3n
4n
C.
3n
In angiosperms, the endosperm development precedes embryo development. One sperm nucleus fertilizes the egg cell, forming a zygote, while the other sperm nucleus usually fuses with the binucleate central cell, forming a primary endosperm cell or PEC. Therefore, the cell created during double fertilization develops into the endosperm.
Identify the correct pair of statements.
I. White kernal of coconut is a free nuclear endosperm.
II. In dioecious plants, autogamy is prevented but geitonogamy occurs.
III. Cleistogamous flowers are always selfpollinated.
IV. Castor is an endospermic seed.
II, IV
II, III
I, II
III, IV
D.
III, IV
Statement III and IV are correct.
(III) Cleistogamous flowers never open, so there occur only self - pollination.
(IV) In castor, endospermic seeds are present. These seeds are also known as albuminous seeds. In this type of seeds endosperm grows vigorously and is not completely exhausted by the developing embryo. Cotyledons in this plant are thin.
In Zostera, the marine angiosperm, the pollen grains are long ribbon-like and without exine. They have same specific gravity as that of water. How is this feature helpful in their pollination?
The pollen grains become unwettable
The pollen grains spread over large and they are lighter
The pollen grains can float below the surface of water
None of the above
C.
The pollen grains can float below the surface of water
In Zostera, the marine angiosperm, the pollen grains are long ribbon-like and without exine. They have some specific gravity as that of water. The pollen grains can therefore, float below the surface of water. This helps in their pollination.
Endothecium and tapetum are formed from
primary sporogenous tissue
primary parietal layer
primary parietal layer and sporogenous tissue respectively
sporogenous tissue and primary parietal layer respectively
B.
primary parietal layer
Endothecium is a type of tissue in anthers that lead to dehiscence. It secretes materials that are essential for the proper maturation of the pollen grains.
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.
They both are formed from primary parietal layer.
Embryo rescue is resorted to
obtain new generation of plants quickly
to reduce chance of seedling growth
ensure growth of interspecific hybrids
induce somaclonal variations
C.
ensure growth of interspecific hybrids
Embryo rescue is resorted to ensure growth of interspecific hybrids. In this method, fragile embryos from fertilised ovules of interspecific crosses are taken out and cultured to form viable hybrid seedlings, e.g. jute, tomato, bean, rice, etc.
Apomictic embryos in citrus arise from
synergids
maternal sporophytic tissue in ovule
antipodal cell
haploid cell
B.
maternal sporophytic tissue in ovule
Synergids, antipodal cell, diploid egg don't take part in seed or apomictic seed formation because they are haploid and take part in sexual reproduction. Only maternal sporogenous tissues in ovules takes part in seed formation in apomictic embryogenesis.
Following are the statements regarding sexual reproduction in flowering plants.
I. Parthenium is a plant that causes pollen allergy.
II. If tapetum is destroyed, then unfeasible male gametophytes are produced.
III. Egg apparatus has 3 synergids and 2 antipodal cells.
IV. Megaspore is the first cell of gametophytic generation.
Choose the incorrect option.
I and II
II and III
III and IV
I and IV
C.
III and IV
Statement I and II are correct.
As the pollens of Parthenium plant can cause pollen allergy. The malfunctioning of tapetum does not nourish the developing pollen grains, thus fails to produce viable male gametophyte. In an embryo sac, there are 2 synergids + 3 antipodal cells + 1 egg cell and 1 polar nuclei. Microspore or pollen grain is the first cell of gametophytic generation.
Parthenogene embryos in plants are those which are formed by
unfertilised eggs
fertilised eggs
sporophytic cells
male gametophyte
A.
unfertilised eggs
Parthenogenesis is the process of development of embryo from an unfertilised egg. This process can be natural as well as artificial i.e., can be introduced by hormone treatment (auxin), while fertilised egg, always form normal embryo.
Match the following columns
| Column I | Column II |
| A. Zoophily | 1. Pollination by birds |
| B. Ornithophily | 2. Pollination by insects |
| C. Entomophily | 3. Pollination by bats |
| D. Chiropterophily | 4. Pollination by animals |
A - 4; B - 1; C - 2; D - 3
A - 1; B - 2; C - 3; D - 4
A - 3; B - 2; C - 1; D - 4
A - 4; B - 2; C - 1; D - 3
A.
A - 4; B - 1; C - 2; D - 3
| Column I | Column II |
| A. Zoophily | 4. Pollination by animals |
| B. Ornithophily | 1. Pollination by birds |
| C. Entomophily | 2. Pollination by insects |
| D. Chiropterophily | 3. Pollination by bats |
The scutellum observed in a grain of wheat or maize is comparable to which part of the seed in other monocotyledons?
Endosperm
Cotyledon
Plumule
Aleurone layer
D.
Aleurone layer
Scutellum is the tissue in a grass or wheat or maize seed that lies between the embryo and the endosperm. It is the modified cotyledon being specialised for the digestion and absorption of the endosperm.
The reduction division in chromosomes takes place in
pollen grains
tapetum
megaspore cell
megaspore mother cell
D.
megaspore mother cell
The reduction division in chromosome occurs in 'megaspore mother cell'.
After pollination the number of chromosome in egg will be
n
2n
3n
None of these
B.
2n
After pollination, the number of chromosomes in fertilized egg will be 2n.
Double fertilisation is the
fertilisation of two eggs in an embryo sac
fusion of one male gamete with the egg cell and another male gamete with the secondary nuclei
fusion of two male gametes with two polar nuclei
fusion of one male gamete with secondary nucleus
B.
fusion of one male gamete with the egg cell and another male gamete with the secondary nuclei
Double fertilization is the fusion of one male gamete with the egg cell and another male gamete with the secondary nuclei. It was discoverd by Nawaschin in 1898.
The development ofsporangium in Pteridium is
a leptosporangiate type
an eusporangiate type
Both (a) and (b)
None of the above
A.
a leptosporangiate type
In leptosporangiate type development a sporangium develops from a 'single initial cell' like in Pteridium, Pteris and Marsilea, etc.
What type of sorus is present in Nephrolepsis?
Coenosorus
Simple
Mixed
None of these
C.
Mixed
Sporangia arise without any order of development, therefore, called mixed type, e.g., Nephrolepis.
In a flowering plant, archesporium gives rise to
wall and tapetum
only tapetum and sporogenous cells
only wall of the sporangium
both wall and sporogenous cells
D.
both wall and sporogenous cells
The archesporial cells divide periclinally, cutting off primary parietal layer (forming wall later on) towards the outer side and primary sporogenous cells towards the inner side.
The aleurone layer in maize grain is specially rich in
starch
lipids
protein
cellulose
C.
protein
In monocotyledons the seeds are generally endospermous. It is surrounded by a special one cell thick layer called aleurone layer. It is filled with aleurone grains which are proteinaceous in nature. Other components of this layer are phytin, carbohydrates and small amount of phospholipids are also present.
The growth of pollen tube towards embryo sac is
geotropism
chemotaxis
thigmotaxis
phototaxis
B.
chemotaxis
The growth of pollen tube towards ovary is due to chemical stimulus and is called chemotropism or chemotaxis.
Geotropism is the growth of the parts of plants in response to the force of gravity. The upward growth of plant shoots is an instance of negative geotropism ; the downward growth of roots is positive geotropism.
Thigmotaxis is the motion or orientation of an organism in response to a touch stimulus.
Phototaxis is the bodily movement of a motile organism in response to light, either towards the source of light ( positive phototaxis ) or away from it ( negative phototaxis ).
A hyaline bisexual and self-fertilized flower that does not open at all is
chasmogamaus
apogamous
cleistogamous
polygamous
C.
cleistogamous
A hyaline, bisexual and self-fertilized flower that never opens is called cleistogamous flower, while chasmogamous flowers expose their mature stigma and anthers to the pollinating agents.
Cleavage polyembryony occurs in
Pinus
Mini Cycas
Cycas
Ephedra
A.
Pinus
Polyembryony is the formation of more than one embryo from a single fertilized ovum or in a single seed. It is found in the conifers and have cleavage polyembryony. In this case all the four cells of the young embryo separate and develop into 4 embryos, but only one complete development and others abort.
Ruminate endosperm occurs in
Annonaceae/Areca nut
Compositae
Cruciferae
Euphorbiaceae
A.
Annonaceae/Areca nut
Mature endosperm with any degree of irregularity and uneveness in its surface contour is called ruminate endosperm. Ruminate endosperm occurs in about 32 angiosperm families (Annonaceae also).
The edible part of apple/ pear is
cotyledons
thalamus/ receptacle
mesocarp
endocarp
B.
thalamus/ receptacle
The edible part of fruit of apple/ pear is thalamus/ receptacle. The fruit is pome (false fruit or pseudocarp) where thalamus is enlarged to form fleshy part.
What is true about a gamo spermous apospory?
Formation of embryo from egg of embryo sac proliferated from a nucellar cell
Formation of embryo from egg of embryo sac formed directly from megaspore mother cell
Formation of embryo directly from nucellus
Formation of embryo directly from integument
A.
Formation of embryo from egg of embryo sac proliferated from a nucellar cell
Apospory is the formation of embryo sac (gametophyte) directly from sporophytic structure.
Seed which are able to withstand reduction in moisture and temperature are called
dormant seeds
recalcitrant seeds
orthodox seeds
non- viable seeds
C.
orthodox seeds
Orthodox seeds are the seeds that survive drying or freezing during ex- situ conservation. These are long- lived seeds and can be successfully dried to moisture contents.
A dormant seed is one that is unable to germinate in a specified period of time under a combination of environmental factors that are normally suitable for the germination of the non- dormant seed.
Recalcitrant seeds are seeds that do not survive drying and freezing during ex-situ conservation and vice versa.
Non- viable seeds are the seeds that do not germinate even if all the favourable conditions needed for germination are provided.
Anthesis means
growth of pollen tube inside the carpel
dehiscence of anthers
opening of floral bud
emergence of anthers
B.
dehiscence of anthers
Anthesis is the flowering period of a plant, from the opening of the flower bud.
Outgrowth developing along with hilum of the seed is:
Plumule
Radicle
Strophiole
Perisperm
C.
Strophiole
Strophiole is the outgrowth developed along with hilum of the seed.
Removal of top fertile soil by wind or water is :
Siltation
Soil erosion
Weathering of soil
Leaching
B.
Soil erosion
The loss of top soil or disturbence of soil structure by wind or water is called soil erosion.
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