(iv) Birds-pollinated or ornithophily flowers are tubular or cup-shaped and produc They are brightly coloured to attract birds from long distances. Examples are; Biguonit (wv) Elephop! © e Vallisneria, pollination takes place by the agency of: (a) Water (8) Wind (©) Birds {D) Insects ‘ans. Option (A) is correct. Explanation : In Vallisneria, pollination takes place by the agency of water. Female flowers have long stalkand appears on the surface of the water. When the male flower releases pollen grain it reaches to the stigma of female flower through water current. Name the two kinds of pollination. Self-pollination and cross-pollination. Name the following: () Pollen of flower cannot reach the stigma of the same flower. (ii) The process of transfer of pollen grains from anther to the stigma. (i) Herkogamy. (ii) Pollination, Give an example for each of the following : () Dichogamy. (i) Herkogamy. (Sunflower. (ii) Pansy. 1 Mark Questions Q2 Ans. Q3. Ans. a4 Ans. By 2 Marks Questions Q.1. Choose the ODD one out from the following terms given and name the CATEGORY to which the others belong: Heterostyly, Autogamy, Geitonogamy, Xenogamy Ans. Heterostyly is a condition of having styles of different lengths relative to the stamens in the flowers of different individual plants, to reduce self- fertilization while others are types of pollination. Q.2. State two advantages of cross pollination. ‘Ans. Advantages of cross pollination : ( Plants grown by cross pollination are healthier and more viable. (ii) New varieties are produced by cross pollination as two different varieties of the same species are involved. Q.3. State two advantage of self-pollination. Ans. Two advantages of self pollination: (i) Avoids wastage of pollen grains. i) Purity of the race is maintained. ., POLLINATION AND FERTILIZATION | 44 Bes .e large quantity of nectar. ‘Canna. ;rains from the anther of the f the anther flower on the is the pollination affected by elephants, Example : Rafflesia. Q.5. Define geitonogamy- Ans. The transfer of pollen g1 flower to the stigma of same plant. Q.6. In which type of pollination new varieties are produced? Ans. Self-pollination, Q.7. Give any two examples of ornithophily flowers. Ans. Bignonia and Canna, Q..8. What part of the flower becomes seed of the fruit? Ans. Ovule. not Commonly Made Error Students confused in between different female : arts of flower. Answering Tip > Learnall the terms with their meaning carefully 1 ____toavoid confusion. (Q5- What are the protective Ans. Integuments. Commonly Made Error | = Most of the students get confused and write incorrect advantages of self -pollination. Many of them write advantages of cross-pollination. Answering Tip | Students must have a clear understanding of the self-pollination and cross- pollination along ith their advantages. ‘GLA. State two disadvantages of cross pollination. ‘Ans. Two disadvantages of cross pollination are : (i) Cross pollination depends upon external agency. (ii) Ttmay lead to Wastage of pollen when wind or ‘water is the pollinating agent.i i rotand = Q.5. Give two examples each of wind, water and insect Q. 6. Differentiate between protandry and Protogy pollinated flowers. Ans. Examples of wind- pollinated flowers- Maize and Pine. Examples of water- pollinated flowers- Vallisneria and Hydrilla, Examples of insect-pollinated flowers- Dahlia and Sweet pea. 3 Marks Questions Q.1. State the name of the chief pollinating agent of the following flowers: () Datta, (ii) Maize. (i i) Insect. (ii) Wind. (iii) Water. Differentiate between the following pairs on the basis of what is given in the brackets : Wind-pollinated flower and Insect-pollinated flower (Flower character). Wind-pollinated flower is small, dull in colour and does not produce scent or nectar. On the other hand, insect pollinated flower is large, bright in colour and emits scent to attract insects. Mention any three contrivances in flowers which favour cross-pollination. ‘The three contrivances in flowers which favour ross-pollination are : () Unisexuality. (i) Dichogamy. Gi) Selt-sterility. Explain the following terms: () Omithophlily. 5 Marks Questions Q.1. Give appropriate biological / technical terms for the following: Vallisneria. Ans. Q2 Ans, on Ans. Q4. (Different timings of maturation of androecium and gynoecium, (i) Pollination of a flower from the pollen of a flower of another plant of the same species. (iii) When stigma and anther of the flower grow at different height and do not favour self- pollination. (iv) Pollen of the same flower fail to germinate on the stigma of the same flower, (v) The flower may be either male or female and they may be bome on separate plants. conditions. Ans. In protandry, anthers’ mature earlier y) gynoecium of the same flower. Examples : san" Sunflower. j In protogyny, pistls mature earlier than stigma same flower. Examples : Custard apple, Peepal, (ii) Elephophily. j ii) Anemophily. | Ans. (i) Ornithophily is the pollination of flowering plants by birds. | (ii) Elephophily is the pollination affected by elephants. (iii)Anemophily is the pollination of flowering plants by wind, Q.5. The diagram given below represents a process occurring in a flower. Answer the questions that follows : oy Ie (i Name the process and explain (ii) Mention the agent involved in the above Process. Ans. (i) The process occurring is entomophily. Entomophily is a form of pollination whereby pollen grains is transferred from the anther to the stigma of a flower by an insect. (ii) The agent of pollination involved in the above Process is an insect, Ans. (i) Dichogamy. i) Allogamy. (ai) Heterostyly, (iv) Self-sterility. (¥) Unisexuality. 2.2. Complete the following paragraph by filling in the blanks (i) to (x) with appropriate words : (@_is the process of transfer of (ii)_from the anther to the stigma. The anthers of the (iii) Produce powdery particles called Each Pollen grain contains (v)_that participates in reproduction. To initiate the process of formation of (vi)_and (vii)_, the pollen grain must firstA POLLINATION AND FERTILIZATION — 43 reach (viii)_. When pollen of the same flower (ii) Pollination by birds is called as ornithophily. vilen of ater Howes al Ga Whereas — Gy Par ’X’isaigmn and part" sbi, test called (me Mant (iv) ‘Two adaptations of flowers showing, ‘ns (i) Pollination isthe process of transfer of (i palten mnithophily ae a . from the anther tothe stigma. Theanthersa (a) Flowers have to produce large amount of the (iii) stamen produce powdery particles called nectar, (ivy pollen grains. Each pollen grat conte nuclei that participate in reproduction. To initiate bird to sip the nectar. the ore formation of (vi) fruit and (vii) seed, (v) To trap pollen, stigma has sticky surface on Wives pollen of the none enc the (oi) stigma, Which the pollen sticks. sigma, it is called (i) atogerny, ae Ov Q.4, What are the advantages of having the following pollen of another flower of the same plant falls on Hiv the Hewes of the Blank concen the stigma, itis called (x) geitonogamy,. @ (vy (b) Flowers are funnel-shaped to enable the Fragrant nectar. (ii) Long and feathery stigma. Protruding and easily movable anthers. (iv) Brightly coloured petals. (v) Smooth and light pollen. Ans, (i) Attracts insects for stigma pollination. (ii) Long and feathery stigma helps to trap pollen grain in wind-pollination. (ii) Protruding and easily movable anthers can move by slightest wind which may help in wind pollination. Commonly Made Error Most of the students were not aware of the like Read up and try to understand all the definitions related to plant poll ~ (iv) Brightly coloured petals attract insects for Q.3. Given below is a diagram depicting a pollination. physiological process in plants. (v) Smooth and light pollen can easily be carried Study the same and answer the following away by wind which enables wind-pollination. questions : Q.5. State any five differences between self-pollination x and cross-pollination. | Anther: Ans. [Sz] Self-pollination | Cross-pollination No. 1. |The pollen grains |The pollen grains are transferred from | are transferred from the anthers to the | the anthers to the | stigma of the same | stigma of another \ flower. flower of a different plant of the same species, ; 2. | Itoccurs in a closed | It occurs in an open (i) Name the process occurring in the diagram. oropen flower | flower. (ii) Explain the process mentioned in part (i). 3, | Ik does not require (ii) Label the parts “X’ and Y’. It requires an exter- | an external agency | nal agency or agent. (iv) Write two adaptations of flowers showing this or agent. process. 4. | Parental characters | Parental character (¥)_ How does stigma trap the pollen? are preserved. are not preserved. Ans. (i) The process occurring in the diagram shows 5. [It does not yield| New varieties are omnithophily by birds. new varieties. produced. ne.Ovule. Nucellus Polar Nuclei POLLINATION AND FERTILIZATION ‘Antipodal cells, Integuments Pollen tube Fig. 4.3 : Ovule showing embryo sac in it and the entry of pollen grains inside it. 1 Mark Questions Q.1, Exine and intine are the parts of (A) Embryo sac (B) Pollen grain (©) Stigma (D)Seed Ans. Option (B) is correct. Explanation : Exine and intine are the parts of a pollen grain. Intine is the inner layer of a pollen grain whereas exine is the outermost protective layer of the pollen grain. Q.2. Give appropriate biological / technical terms for the following: A fruit that develops without fertilization. ‘Ans. Parthenocarpic fruit Q.3. State the function of micropyle. fa Ans. Micropyle helps in absorption of water that is available to the embryo for germination. 2 Marks Questions Q.1. Given below are sets of five terms each. Rewrite the terms in correct order in a logical sequence be- ginning with the term that is underlined. (i) Intine, Exine, Germ pore, Generative nucleus, Tube nucleus. (i) Pollen grain, Stigma, Embryo sac, Pollen tube, Ovary Ans. (i) Exine, Germ pore, Intine, Generative nucleus, Tube nucleus. (ii) Embryo sac, Ovary, Pollen tube, Stigma, Pollen grain. Q.2. Name the following : ()_ Fusion of male gamete with two polar nuclei. (ii) Cell formed by the fusion of a male gamete with the egg cell. Ans. (i) Triple fusion. (ii) Zygote. Q.4, How many cells are there in an embryo sac? [a[i) Ans. 7 cells. Q.5. What are the three cells at the opposite end of micropylar end of the embryo sac called? Ans. Antipodal cells. Q.6. Name the nucleus formed after the triple fusion. Ans. Endosperm nucleus. Q.7. What is syngamy? ‘Ans. The process of fusion of one sperm nucleus with the egg nucleus to form an embryo is called syngamy. Q.8. Where is the embryo sac located? ‘Ans. Embryo sac is located inside the nucellus. Q.3. What is ‘Double Fertilization’? ao Ans. Double fertilization is a process, in which out of the two sperm nuclei, one sperm nucleus fuses with the egg nucleus to form an embryo (process is called syngamy) and another fuses with the secondary nucleus to form endosperm (process is called triple fusion). As this process involves two kinds of, fusion—syngamy and triple fusion therefore, the process is known as double fertilization. Q.4, Mention the exact location of the following : (@) Ovule. (ii) Potten sac. Ans. (i) The ovule is located inside the portion of the flower called the gynoeciuim, (ii) Pollen sac is found inside the anther. Q.5. Whatis the difference between a fruit and a seed? Ans. Fruit develops from whole embryo while seed develops from the ovule. oi3 Marks Questions Q.1. Name the parts of the ovary which give rise to ‘aa (i) Seed. i) Fruit. (iii) Fruit wall. Ans. (i) Ovule, ii) Ovary. Ovary wall. Q.2. State differences between seed and ovule. Ans. The differences between seed and ovule are Ovule Tt is present inside the ovar Seed 1. Itis present inside the fruit, a Q.3. How does a pollen tube reaches the embryo sac? Ans. The pollen tube grows through the stigma and style by dissolving the tissues with the help of enzymes and reaches the ovary. On reaching the ovary, the pollen tube pushes through the micropyle and reaches the embryo sac. ; Q.4. What is the main function of pollen tube? Explain it with the help of a diagram. Ans. The function of pollen tube is to carry male gametes to the ovules for the fusion with female gamete. Generative nucieus, Exine Py It develops when the male gamete fuses with the fe- male gamete pres- ent inside the ovule. It is produced post- fertilization. ‘The embryo sac present inside it, contains the female gamete. It is _pre-fertilization female reproductive structure, XQ] 5 Marks Questions Q.1. Study the diagram given below and answer the questions that follow : ©) (i) Identify the above structure and mention its location in a flower. (ii) Label the parts numbered 1 and 2, (iii) Explain the term ‘Double fertilisation’, (iv) What is the fate of the calyx and corolla after fertilisation? () Draw a neat, labelled diagram of a pollen grain, Ans. (i) It is the structure of an embryo sac. The embryo sac develops within an ovule, which is, contained within the ovary ofa flower. ii) Part 1 is antipodal cell at chalazal end while Part 2is polar nuclei. (iii) Double fertilisation is a process in which out of the two sperm nuclei, one sperm nucleus fuses with the egg nucleus to form an embryo (process is called syngamy) and Pete Nucleus. another fuses with the secondary nucleus to form an endosperm (process is called triple fusion). Since, it involves two kinds of fusion— syngamy and triple fusion— the process is known as double fertilisation. (iv) Both the calyx and corolla fall off or remain dried and shrivelled in some cases. (w) Vegetative nucleus cell Generative nucleus Q.2. Study the diagram given below and answer the questions that follow :(Name the structure shown and label its parts ‘1,2 and ‘a’, (ii) State the difference in parts labelled as’3" and s. i) Name the cells of the embryo sac. (iv) Describe the function of micropyle, (v) What is the fate of ovule and ovary after fertilization? Ans. (i) The structure is longitudinal section of an ovulle Part 1 is nucellus, part 2is embryo sac, and part is micropyle. Part’ is integument and part ‘5’ is funicle, Integument is the protective layer of ovule whereas funicle isa filamentous stalk attaching, a seed or ovule to the placenta, i) (iii) Embryo sac has 7 cells namely 3 antipodal cells, egg cells, 2 synergids and a central cell with polar nuclei. Micropyle provides a route for pollen grains to enter into the ovule, After fertilisation, ovules become seeds and the ovary becomes the fruit. i) ) ANN Commonly Made Error A Most of the students name the parts incorrectly. Therefore, they write incorrect distinction between the function of these parts. @ ‘Name the parts labelled 1,2,3,4 and 5. (ii) Where does the germination of the pollen grain takes place and how? (iii) What is the function of the part labelled ’4’. (iv) What happens to the part labelled ‘5’ during the process? POLLINATION AND FERTILIZATION Part 1 Exine Part 2-Intine Part 3- Pollen tube Part 4 - Tube nucleus Ans. (i) 47 7 Part 5 - Generative nucleus, ‘The germination of the pollen grain takes place on the stigma of the same plant species. When the pollen grain falls on stigma, the secreted sugar of stigma stimulates it to germinate. As a result pollen tube grows out through a point in the exine. The part ‘4’, which is a tube nucleus directs the growth of pollen tube all the way down to the ovary. During the process, the part 5, which is a generative nucleus divides into two nuclei called male gamete nuclei or sperm nuclei. (iii) (iv) Commonly Made Error } & Students are often unable to identify the parts id thi ide rand Answering Tip Practice self-explanatory diagrams and understand the function of different parts of 1 _____the pollen grain, Q.4. Given below is a diagrammatic representation of the process of fertilization. Study the same and then answer the questions that follow : (2) Name the parts labelled 1, 2,3, 4,5 and 6. (b) What happens to (i) Ovary (ii) Ovule after fertilization? What is the function of the synergids? What part does the stigma play in the process of fertilization? Egg cell SynergidsAns, (4) (Stigma receives the pollen @ 4 ‘art 1- Style. carry male gametes for fertil ‘art 2- Pollen tube, (iiyThe secretion of su Part 3 - Polar nuclei, stimulates the pollen ins wht ins wt zation," Bat by the stigma Brain to geri Part 4 - Embryo sac. and reach the ovary for fetilizations oe Part 5 - Antipodal cells Q.5, Mention whether the following sty Part 6 - Micropyle. True or False? fements are (b) After fertilisation: i) Fertilisation is the fusion of anther a (Ovary enlarges to form a fruit stigma, Gi) Ovutes become the seeds. i)" Anemophilous flowers ae large and bright (©) Synergids provide a way for the entry of ii) Valisnera flowers are pollinated by aner pollen tube in into the embryo sac and receive iv) Anemoph ily means pollination by insects, ¥)_ Wind pollination occurs in maize plant Ans, i) False, ii) False, ii) False, the two sperm nuclei. iv) False, v) True. Ey Key Words A > v vy vvy . elien tube : The pollen tube grows through the stigma and style by dissolving the tissues with the help of enzymes to reach the ovary. Artificial pollination : When man himself transfer pollen to the stigma, it is called artificial pollination, Emasculation : The removal of anthers in a bisexual flower to prevent self-pollination. Cieistogamy : Its a condition in which flower does not open. Its an adaptation seen in plants to ensure self pollination, Parthenocarpy : I is the formation of a seedless fruits, Oospore: Other name of zygote. Polyembryony : Formation of more than one embryo. Parthenogenesi + Formation of new individual from a single gamete without fertilization, goa