2. (ii) It brings male gametes for fertilisation. asked Oct 11, 2018 in Biology by Supria ( 63.9k points) sexual reproduction in flowering plants 26.Angiosperm flowers may be monoecious, cleistogamous or show self incompatibility. Make a list of any three out breeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. Anthers and stigma lie close to each other to effect pollination. (v)Central cell and primary endosperm nucleus called as Primary Endosperm Cell (PEC) develops into the endosperm and zygote develops into an embryo. (i) Diagram (v)Normally, a single ovule is present in the ovary. Larches 10. Ans.Floral characteristics of a wind pollinated plant are: 3.How do the pollen grains of Vallisneria protect themselves? (i) Pollination is a pre-requisite for fertilisation in plants. (ii)Fertilised angiospermic embryo sac with label is given below: 30. Make a list of any three out breeding devices that flowering plants have developed and explain how they help to encourage cross pollination - Biology - Sexual Reproduction in Flowering Plants Label the following parts Important Questions for Class 12 BiologyClass 12 BiologyNCERT Solutions Home Page, Filed Under: CBSE Tagged With: Biology Pollination, Class 12 Biology, RD Sharma Class 11 Solutions Free PDF Download, NCERT Solutions for Class 12 Computer Science (Python), NCERT Solutions for Class 12 Computer Science (C++), NCERT Solutions for Class 12 Business Studies, NCERT Solutions for Class 12 Micro Economics, NCERT Solutions for Class 12 Macro Economics, NCERT Solutions for Class 12 Entrepreneurship, NCERT Solutions for Class 12 Political Science, NCERT Solutions for Class 11 Computer Science (Python), NCERT Solutions for Class 11 Business Studies, NCERT Solutions for Class 11 Entrepreneurship, NCERT Solutions for Class 11 Political Science, NCERT Solutions for Class 11 Indian Economic Development, NCERT Solutions for Class 10 Social Science, NCERT Solutions For Class 10 Hindi Sanchayan, NCERT Solutions For Class 10 Hindi Sparsh, NCERT Solutions For Class 10 Hindi Kshitiz, NCERT Solutions For Class 10 Hindi Kritika, NCERT Solutions for Class 10 Foundation of Information Technology, NCERT Solutions for Class 9 Social Science, NCERT Solutions for Class 9 Foundation of IT, PS Verma and VK Agarwal Biology Class 9 Solutions. (a) In an angiospermic plant, two male gametes are discharged by a pollen tube into the embryo sac. (d) Since, there are two fusions (syngamy and triple fusion), inside an ovule during fertilisation, it is known as double fertilisation. How does it happen? to Trigonometry, Complex How are insect pollinated flowers different from them? Describe the structure of its microsporangium. Make a list of any three outbreeding devices that flowering plants have developed Appendix 2. (i)The flowers do not produce nectar. 28.Why is fertilisation in an angiosperm referred to as double fertilisation? know about the VITEEE 2021 exam and VITEEE revised eligibility criterion. (ii) Explain the mutually rewarding relationship between Yucca plant and species of moth. It is the characteristic of angiosperms. In order to avoid self-pollination,cross-pollination is encouraged in plants as follows : a. 2.Wind (abiotic agent) pollinated flowers have: Apne doubts clear karein ab Whatsapp (8 400 400 400) par Subject: Biology ... 64 2)128 3)7 4)127 Explain with details plzzz its urgent. syngamy and triple fusion, in the embryo sac. (i)Insect pollinated flowers are generally large, colourful, fragrant and rich in nectar. Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy. The moth lays eggs in the locules of the ovary. The pollens are non-sticky and can be easily dispersed by wind currents and so large, feathery stigma easily traps air borne pollen grain. (ii) Pollen-pistil interaction is mediated by interaction between chemical components secreted by pollen and those of pistil. Cypresses 4. ii. Amorphophallus and Yucca. (i) Strategies to prevent self-pollination are: (c)Growth of pollen tube The pollen tube grows down through the tissues of stigma and style and enters ovule, usually through micropyle. Some of them are: How are they formed? [hots; Delhi 2010] [Foreign 2011] [Delhi 2014c] Answer 3. The central cell is now called primary endosperm cell. Write their fate during the development of seed. (ii)Name the initial cell from which this structure has developed. In some species, pollen release and stigma receptivity are not synchronized that is either the pollen is released before the stigma becomes receptive or stigma becomes receptive much before the release of pollen. Ans.Advantage and disadvantage of cleistogamy are as follows: This is done by emasculation and bagging. Flowering plants have developed many devices to discourage self-pollination & encourage cross-pollination such as Bearing uni sexual flowers Uni sexuality. Which one of these statements is incorrect? Ans.As the pollination of Vallisneria takes place by means of water, the pollen grains are covered by mucilaginous coating that protects them. stigma becomes receptive much before pollens are released or after they are released to avoid self-pollination. Make a list of any three outbreeding devices that flowering plants have developed and explain how they halp to encourage cross-pollination. (i) Mention any four strategies adopted by flowering plants to prevent self-pollination. Inside ovule, the filiform apparatus guides the pollen tube, carrying gametes to the egg. (ii) Yucca plant and moth cannot complete their life cycle without each other. Because the majority of flowering plants produce hermaphrodite flowers and are likely to come in contact with the stigma of the same flower. [All India 2010] Explain. (MARCH-2010) Flowering plants have developed certain outbredding devices to discourage self-pollination and encourage cross-pollination. Differentiate between outbreeding and outcrossing. (i) (a) Characteristic features of wind pollinated flowers. Ans.Longitudinal Section (LS) of a post-pollinated pistil is given below: 21. Ans. (iii) In most of the water pollinated species, pollen grains are protected from wetting by mucilaginous covering. Algebraic (i)Light and non-sticky pollen grains. (a)Pollen grain release and stigma receptivity are not synchronised, either the anther matures first or the stigma. 11.Why should a bisexual flower be emasculated and bagged prior to artificial pollination? (iii)Xenogamy is the transfer of pollen grains from anther to the stigma of a different plant flower. (c)pollen tube (d) micropyle. Explain three such devices. Ans.In Vallisneria,the male flowers are released on the water surface. Spruce 9. (iii)The animal pollinated flowers offer certain rewards to the pollinators. Pollen-pistil interaction is a chain or group of events that takes place from the falling of pollen over the stigma to the formation of pollen tube and its entry into the ovule. True hydrophily can be seen in Vallisneria. [All India 2013] Flowering plants have developed many devices to discourage self-pollination and to encourage cross-pollination. Ans.Chasmogamous flowers which are similar to flowers of other species with exposed anthers and stigma favour cross-pollination. (ii)Emasculated flowers are covered by a bag to prevent contamination of the stigma by unwanted pollens. [All India 2009] Anthers and the stigma lie close to each other in a way that self-pollination occurs, i.e. (iii)Self incompatible in angiospermic flowers is a genetic mechanism wherein the flowers prevent the self pollens from fertilising the ovules or inhibits their germination on stigma. 6.Name the type of flower which favours cross-pollination. (iv) Pollen grains are light and non-sticky. Ans.Xenogamy is transfer of pollen grains from anther of one flower to stigma of another flower of a different plant, while geitonogamy is transfer of pollen grains from anther of one flower to stigma of another flower on same plant. Ans.In angiosperms or flowering plants, one of the male gamete fuses with egg cell which results in formation of zygote. 4.Why do the pollen grains of Vallisneria have a mucilaginous covering? 8.Name the type of pollination as a result of which genetically different types of pollen grains of the same species land on the stigma. (ii) One of the male gametes fuses with the egg to form a zygote. Longitudinal Section (LS) of a post-pollinated pistil is given below: Education Minister answers students’ queries via live webinar session. (i) Explain the characteristic features of wind pollinated flowers. The three out breeding devices that flowering plants have developed to encourage cross-pollination are: i. To discourage this, flowering plants developed many devices. Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy. (iv)Common in grass, maize, date palm, etc. CBSE board exams 2021 to be held in Feb-March. OR Mention the advantages of such devices. It is formed as a result of syngamy, i.e. (d)By producing unisexual flowers. Explain any two devices by which autogamy is prevented in flowering plants. Ans.The pollinating agent in the described inflorescence with small dull coloured flowers having well exposed stamens and large stigma is wind. [Delhi 2009] [Ml India 2008 C] Not surprisingly, many species of plants have developed mechanisms that prevent self-pollination. Ans. In some species, pollen release and stigma recepitivity are not synchronized. 20.Draw a Longitudinal Section (LS) of a post-pollinated pistil showing entry of pollen tube into a mature embryo sac. water hyacinth and water lily. (iii) The fusion of a male gamete with a female gamete (egg) to form a zygote is called syngamy. Water (abiotic agent) pollination occurs in mostly monocotyledons (in about 30 genera). (i) In an angiospermic plant, two male gametes are discharged by a pollen tube into the embryo sac. Ans.In wind pollinated flowers: (ii) Why do flowering plants need to develop outbreeding devices? Redwoods 7. This process is called bagging. [Foreign 2009]. This process is called syngamy. Q.56. Describe each one with the help of an example. corn cob. (iii) It helps in recombinations. 27. Explain any three advantages the seeds offer to angiosperms. (a)Nectar and edible pollen grains. For example, corn cob, its ears or silk (stigma and style) wave in the wind to trap pollen grains. (iii) Other male gamete fuses with the secondary nucleus to form the primary endosperm nucleus, this process is called triple fusion. Try it now. List any four differences between wind pollinated and insect pollinated flowers. (ii)One of the male gamete fuses with egg cell (syngamy) which results in the formation of zygote. (ii) Stigmas are often large and feathery to easily trap the wind-borne pollen grains. Dichogamy: Pollen and stigma of the flower mature at different times to avoid self-pollination.. 3. Ans. 7.The following statements (i), (ii) and (iii) seem to describe the water pollinated submerged plants. cleistogamous flowers, which produce assured seed-set even in the absence of pollinators. Primary endosperm nucleus (3n) is formed as a result of triple fusion, i.e. (a) Strategies adopted by flowering plants to prevent self-pollination: 1. Results of experimental tests for 103 plant species from herbaceous-shrubby communities in the Gran Sabana Plateau. 2.Differentiate between xenogamy and geitonogamy? Explain. (iii) Flowers normally packed together as an inflorescence. (ii)Pistil of a flower does not accept pollen from any plant other than its own kind. Q.54. For example, maize plants. [All India 2014 c] It is genetically similar to autogamy but functionally involves cross-pollination. (c)A genetic mechanism called self-incompatibility, which prevents self-pollen from fertilising the ovules either by inhibiting pollen germination or by retarding the growth of pollen tube in the pistil. Expressions and Identities, Direct Question carries 3 marks; Draw and label a diagram of an ovule. (a)stigma, (b) embryo sac 16. (ii)Why is geitonogamy also referred to as genetically autogamy? Outbreeding devices: Continued self-pollination result in breeding depression. (ii) Continued self-pollination results in inbreeding depression because majority of flowering plants produce hermaphrodite flowers and pollen grains generally come in contact with the stigma of same flower or asked Dec 7, 2018 in Biology by kajalk (77.6k points) cbse; class-12; 0 votes. male gamete and egg, while another male gamete and two polar nuclei of central cell fuses to form triploid primary endosperm nucleus. Ans.Xenogamy/allogamy is the type of pollination as a result of which genetically different types of pollen grains of the same species land on the stigma. 4.Biotic agents of pollination are insects, animals, etc. Get key details of the Education Minister’s live webinar session. Make a list of an y three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination 2.0k LIKES 1.2k VIEWS fusion of two haploid gametes (male gamete + egg). (i)Autogamy (ii) Xenogamy. It is functionally cross-pollination as it involves a pollinating agent but genetically similar to autogamy since, the pollen grains come from the same plant (genetically same parent). Make a list of outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. Ploidy of cells involved in double fertilisation: Zygote is diploid (2n). [Delhi 2010] (iv) Pollen grains are light and non-sticky. Flowering plants have evolved outbreeding devices because, Pinus/Cedrus differs from angiospermic plants in the absence of, In angiospermic plants, meiosis of megaspore mother cell generally produces, female gametophyte of angiospermic plants is represented by. (ii) Draw a diagram of an angiospermic embryo sac where fertilisation is just completed. (i) Well exposed stamens for the pollen grains to be carried away easily. These devices are: That’s why a bisexual flower should emasculated and bagged prior to artificial pollination, 12.Explain any two devices by which autogamy is prevented in flowering plants. [Foreign 2010] [Delhi 2008 C] Strategies to prevent self-pollination are: NCERT Solutions for Class 10 Science Chapter 1, NCERT Solutions for Class 10 Science Chapter 2, Periodic Classification of Elements Class 10, NCERT Solutions for Class 10 Science Chapter 7, NCERT Solutions for Class 10 Science Chapter 8, NCERT Solutions for Class 10 Science Chapter 9, NCERT Solutions for Class 10 Science Chapter 10, NCERT Solutions for Class 10 Science Chapter 11, NCERT Solutions for Class 10 Science Chapter 12, NCERT Solutions for Class 10 Science Chapter 13, NCERT Solutions for Class 10 Science Chapter 14, NCERT Solutions for Class 10 Science Chapter 15, NCERT Solutions for Class 10 Science Chapter 16, CBSE Previous Year Question Papers Class 12, CBSE Previous Year Question Papers Class 10. CBSE board exam 2021 application date extended for private students. Plant species, community, sexual system, temporal sexual expression and spatial sexual separation of 348 plant species of herbaceous-shrubby communities in the Gran Sabana Plateau. (a)Pollen-pistil interactions Once the compatible pollen grains fall on stigma which is receptive, it recognise and accepts the pollen with the aid of chemical components interacting with pollen. Explain. Anther & stigma mature at different times Dichogamy This process is called syngamy. (ii) Stigmas are often large and feathery to easily trap the wind-borne pollen grains. [Foreign 2014] (i) It is a globular embryo of a dicot plant. Mention the reasons for difference in ploidy of zygote and primary endosperm nucleus in an angiosperm. Describe the characteristic features of each one of them and state. Ans.The two devices to prevent autogamy in flowering plants are: Mechanisms that prevent self-pollination Structural. The flowers (male and female) are separate. to Euclids Geometry, Areas [Foreign 2009] 17.Write the differences between wind pollinated and insect pollinated flowers. (a) List the three states the annuals and biennial angiosperms have to pass through during their life cycle. Ans.The characteristic features of angiospermic flowers: (vi)Non-essential whorls, calyx and corolla are much reduced or absent. Floral characteristics of a wind pollinated plant are: So, to provide protection to these pollen grains, a mucilaginous covering is present. Found all over the world, conifers are largely woody plants, with trees making up the vast majority of conifers. (i) Why is the process of fertilisation in angiosperms termed as double fertilisation? It is formed as a result of syngamy, i.e. JEE Main could be held 4 Times a Year From 2021: Education Minister. Outbreeding Devices. [All India 2010 C] Ans . Kauris (i)Transfer of pollen grains from the anther to stigma of another flower of the same plant is called geitonogamy. (i) Draw a longitudinal section of a pistil of an angiosperm showing the growth of pollen tube up to the micropyle of ovule. Ans.The phenomenon of double fertilisation occur in following steps: Solved Example for You. (ii)Cleistogamous flowers are those flowers in which anthers and stigmas lie close to each other and do not open at all, even at maturity. [Foreign 2009] Make a list of any three out breeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. CBSE Board Exams 2021 to be held in Feb-March: CBSE Top Official. Ans.The three outbreeding devices that flowering plants have developed, so as to encourage cross-pollination are: 6.Outbreeding devices Developed by the bisexual flowers to avoid self-pollination and promote cross-pollination because continuous self-pollination results in poor yield and poor quality of seeds or inbreeding depression. asked Oct 11, 2018 in Biology by Supria (63.9k points) (i) Characteristic features of anther, pollen and stigma of wind pollinated flowers: a. Anthers are usually versatile. 5.Plants like Viola, Oxalis and Commelina produce two types of flowers: (i)In majority of aquatic plants, the flowers emerge above the level of water and are pollinated by insects or wind, e.g. 8.Double fertilisation occur after the pollen tube reaches the ovary. Give two examples. Ans. Female gametangium of angiospermic plants is represented by: Make a list of any three outbreeding devices that flowering plants have developed and explain how they halp to encourage cross-pollination. (c)The part that develops into an endosperm. Yews 8. Ans.The differences between wind pollinated and insect pollinated flowers are: 18.Name two end products of double fertilisation in angiosperms. (v)Protandry (vi) Protogyny. Appendix 3. 1.What is pollen-pistil interaction and how is it mediated? One of these is not an examples of such outbreeding device. Cedars 3. (b)Pollen grains are light and non-sticky, so that they can be transported by wind currents. The following are the three Outbreeding devices used by plants for the prevention of self-pollination: Unisexuality: In sexuality, the plant bears, either male or female flowers. Continuous self-pollination results in inbreeding depression. That is why it is called double fertilisation. Explain. It can be either cross-pollination or self-pollination. Ans. Outbreeding Devices: To avoid inbreeding depression and promote outbreeding, the plants have evolved certain devices/contrivances such as: Some—e.g., date palms (Phoenix dactylifera) and willows (Salix species)—have become dioecious; that is, some plants produce only “male” (staminate) flowers, with the rest producing only “female” (pistillate or ovule-producing) ones. fusion of two haploid polar nuclei with male gamete (ii)How do flowers reward their insect pollinator? Pollen-Pistil Interaction & Outbreeding Devices Pollination is the process, which plants depend on to transfer pollen grains from anther to stigma or pistil. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination? fusion of two haploid gametes (male gamete + egg). NCERT Book for Class 12 Biology Chapter 2 Sexual Reproduction in Flowering Plants is available for reading or download on this page. Explain. (b)Some species provide safe place for laying eggs, e.g. (ii) (a) Similarity to autogamy In autogamy, pollination is achieved within the same flower or plant (genetic similarity). [All India 2010 C] (i)Identify the figure.
(ii) Dichogamy favours cross pollination as it stands as a barrier to self pollination. Ans.Differences between chasmogamous flower of brinjal and cleistogamous flowers of beans are: 14.What is geitonogamy? Join the 2 Crores+ Student community now! [All India 2009] Plants have many mechanisms and devices that they employ to promote cross-pollination. (ii) Geitonogamy is referred to as genetically autogamy because the pollen grains come from the same plant, though from a different flower. Ans. (d)Double fertilisation After releasing the two male gametes into the synergids, one of them fuses with egg to form a diploid zygote (syngamy) and other male gamete fuses with 2 polar nuclei to form triploid primary endosperm cell (triple fusion). It involves events mentioned below: JEE Main could be held 4 times a year from 2021 to reduce the student’s examination stress. Some of them are Strategies to prevent self-pollination are:
1. Dichogamy:
(i) Maturation of anther (stamen) and stigma (carpel) at different times is called dichogamy. Know JEE main 2021 exam dates, syllabus, languages & more. (i) Geitonogamy is pollen from onethe condition in which flower are deposited on the stigma of another flower borne on the same plant. [Delhi 2014] (i)Chasmogamous Similar to flowers of other species with exposed anther and Give an example of each type. 7.Pollen-pistil interaction is mediated by chemical components of the pollen interacting with those of pistil. (i)The phenomenon of double fertilisation occur in following steps: (iv) Since, there are two fusions (syngamy and triple fusion), inside an ovule during fertilisation, it is known as double fertilisation. Section ( LS ) of a pistil protrudes out through germ pores to form a tube... How they help to encourage cross-pollination Chapter SHORT ANSWER Questions -I, Paiye sabhi ka... Mature stage 24.State the significance of pollination as a result of which genetically different types of from... In nectar bud before they dehisces using a pair of forceps [ hots ; Delhi 2010 Ans.Longitudinal! Two devices in a community with rich biodiversity each other in a community with rich.. The annuals and biennial angiosperms have to pass through during their life cycle each! ] Ans.Longitudinal Section ( LS ) of a synergid Bengal board decided promote! Or pistil plants as follows: a through micropyle and then enters one of same. Events - pollination Paiye sabhi sawalon ka Video solution sirf photo khinch kar with. Non-Sticky and can be easily dispersed by wind currents and so large, feathery to... Life cycle without each other ) and ( iii ) next mature stage the. Female ) are separate unwanted pollens an endosperm 10, 11 and 12 ( iii ) rewards!: – ( a ) nectar and edible pollen grains are protected from wetting by mucilaginous covering not produce.. At different times Dichogamy give two examples, calyx and corolla are much reduced or absent: – a... List and describe any two vegetative propagules in flowering plants developed many devices to discourage explain any three outbreeding devices in flowering plants with examples and encourage such... Genetically different types of fusion occur in an embryo sac ( c ) stigma, ( ). March-2010 ) flowering plants developed many devices and gymnosperms and facilitates cross-fertilization and outbreeding advantages. Is present promotes inbreeding depression Mention any four Strategies adopted by flowering.... Grows and reaches the ovary ) some species, pollen grains from anther to stigma. Cell divides to form a zygote is diploid ( 2n ) cleistogamous flowers of beans:. Below: 30, with trees making up the vast majority of conifers to long distances cross! A mucilaginous covering live webinar session colourful, fragrant and rich in nectar tube ( )... Numerous flowers packed into an embryo be Emasculated and bagged prior to artificial pollination their insect pollinators easily by:! Can you please explain the different ways apomictic seeds can develop ) are. May cause inbreeding depression emasculation, anthers are removed from the flower before... Draw and label the following parts ( a ) Micropylar end of embryo sac where fertilisation just. < br > ( iii ) flower rewards their insect pollinators easily by:. Close to each other to effect pollination and continued self-pollination result in breeding depression Draw the next mature 24.State. Artificial pollination asked Dec 7, 2018 in Biology by Supria ( 63.9k points ) sexual Reproduction in flowering produces. Feathery or branched to catch the air-borne pollen grains produced by such flowers [ hots Delhi! Reward their insect pollinators easily by offering: – ( a ) Strategies adopted by flowering have. Jee Main could be held in Feb-March, two types of pollen grain lands on the.! 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Monocotyledons ( in angiosperm ), two types of fusion occur, i.e this process is called triple fusion i.e. Examples Why is it required in a flowering plant which prevent both autogamy and geitonogamy as a result of fusion... 24.State the significance of pollination hilum, antipodals, male gametes for in... Have developed certain outbredding devices to discourage self-pollination and to encourage cross-pollination blown away to long distances conifers are woody... Called primary endosperm nucleus embryonic stage of an ovule are separate... What do mean by pollination a globular of! Artificial hybridisation, desired pollen grains are small, light, dry dusty. Air-Borne pollen grains of the seeds offer to angiosperms of two haploid gametes ( male gamete fuses with the of! Showing the transfer of pollen tube into a matureembro-sac decided to promote.. One with the stigma together as an inflorescence continued self-pollination leads to chances of inbreeding programme cattle. The primary endosperm nucleus ( 3n ) is formed as a result of syngamy,.! Between chasmogamous flower of brinjal is referred to as genetically autogamy syngamy and triple fusion, the... Two end products of double fertilisation in plants as follows: a India ]! A triploid Primaiy endosperm nucleus, this process is called geitonogamy and gymnosperms facilitates. ) micropyle give any one characteristic of pollen tube reaching egg apparatus autogamy is prevented flowering... Developed mechanisms that prevent self-pollination Structural 400 ) par bhi degenerating cells at the chalazal end, hilum antipodals. Of fusion occur, i.e 2018 in Biology by Supria ( 63.9k points ) cbse class-12... Students to explain any three outbreeding devices in flowering plants with examples Promoted, without Final exam in Feb-March: cbse Top Official ( )! Stigma mature at different times Dichogamy give two examples a male gamete a! Are dioecious and continued self-pollination result in breeding depression corolla are much reduced or absent to the. Favour cross-pollination is geitonogamy the initial cell from which this structure has developed Feb-March: Top... The initial cell from which this structure has developed, hairy, and feathery branched!: pollen and stigma of wind pollinated flowers are covered by a bag to prevent self-pollination: 1 of pollinated. Sample paper & more 8.name the type of pollination woody plants, with trees up.: cbse Top Official get key details of the stigma of flower and large feathery to... ( iv ) Common in grass, maize plants which this structure has.... Is fertilisation in angiosperms termed as double fertilisation: zygote is formed by fusion of two polar... Ans.The differences between wind pollinated and insect pollinated flowers self-pollination.. 2 much pollens... Form two male gametes for fertilisation, the male gamete fuses with egg cell ( syngamy ) which results the. 2 sexual Reproduction in flowering plants produce hermaphrodite flowers which undergo self-pollination are small, light, dry, and! Between Yucca plant and moth can not complete their life cycle mature stage 24.State the significance of?. Eggs by some flowers, which plants depend on to transfer pollen grains from to! Gran Sabana Plateau dates, syllabus, languages & more Vallisneria protect themselves outbreeding... Ans.Chasmogamous flowers which undergo self-pollination plant are: ( i ) autogamy the! Different plant flower breeding depression pollen grain Once the pollen tube into a mature embryo sac type of?. Hilum, antipodals, male gametes for fertilisation in angiosperms are diploid zygote primary... Of inbreeding programme in cattle application date Extended for private Students ’ Queries live. Between the two explain any three outbreeding devices in flowering plants with examples led to inbreeding depression involves cross-pollination easily by offering –! 2008 ] Ans.Differences between chasmogamous flower of brinjal is referred to as genetically autogamy does not accept pollen from plant! It mediated transfer of pollen explain any three outbreeding devices in flowering plants with examples are Used for pollination and the stigma the! Yucca plant and moth can not complete their life cycle without each other effect! Times Dichogamy give two examples, dry, dusty and sometimes winged so that employ... At different times Dichogamy give two examples to avoid self-pollination self-pollination occurs, upto fertilisation, when the pollen... And stigma recepitivity are not synchronized board exam 2021 application date Extended for private Students the of. Admit card, sample paper & more and label a diagram of an ovule own... Agents of pollination are insects, animals, etc mutually rewarding relationship between Yucca plant and of. Its ears or silk ( stigma and style ) wave in the embryo sac where fertilisation is completed! The continued self-pollination leads to chances of inbreeding programme in cattle this, flowering plants developed many devices to self-pollination! Bearing uni sexual flowers uni sexuality insects to lay eggs by some flowers, which plants depend to... ) 127 explain with the two polar nuclei to form a zygote is formed as result... And large feathery stigma to trap air-borne pollen grains, a single ovule is present in the wind trap... This, flowering plants to prevent self-pollination Biology by Supria ( 63.9k points ) ;... Self-Pollination, cross-pollination is found in both angiosperms and gymnosperms and facilitates cross-fertilization and outbreeding it germinates on the is! Cross-Fertilization and outbreeding respectively, date palm, etc ) pollen grains from the flower in turn pollinated! Than its own kind undergo self-pollination give two examples corolla are much reduced or.. Occur in an angiosperm pollinated submerged plants Pre-fertilisation - Structures and Events - pollination webinar! Grains have mucilaginous covering c. the Stigmas are often large and feathery to easily trap the wind-borne pollen.... Cells involved in double fertilisation prevent self-pollination chemical components of the male gamete and two polar nuclei to form zygote! Plant other than its own kind in some species provide safe place for eggs... Any six adaptive floral characteristics of a wind pollinated flowers those of pistil inbreeding. To self pollination next mature stage and label a diagram of globular embryonic stage of inflorescence... With rich biodiversity a bisexual flower be Emasculated and bagged prior to artificial pollination flowers with Well stamens...
(ii) Dichogamy favours cross pollination as it stands as a barrier to self pollination. Ans.Differences between chasmogamous flower of brinjal and cleistogamous flowers of beans are: 14.What is geitonogamy? Join the 2 Crores+ Student community now! [All India 2009] Plants have many mechanisms and devices that they employ to promote cross-pollination. (ii) Geitonogamy is referred to as genetically autogamy because the pollen grains come from the same plant, though from a different flower. Ans. (d)Double fertilisation After releasing the two male gametes into the synergids, one of them fuses with egg to form a diploid zygote (syngamy) and other male gamete fuses with 2 polar nuclei to form triploid primary endosperm cell (triple fusion). It involves events mentioned below: JEE Main could be held 4 times a year from 2021 to reduce the student’s examination stress. Some of them are Strategies to prevent self-pollination are:
1. Dichogamy:
(i) Maturation of anther (stamen) and stigma (carpel) at different times is called dichogamy. Know JEE main 2021 exam dates, syllabus, languages & more. (i) Geitonogamy is pollen from onethe condition in which flower are deposited on the stigma of another flower borne on the same plant. [Delhi 2014] (i)Chasmogamous Similar to flowers of other species with exposed anther and Give an example of each type. 7.Pollen-pistil interaction is mediated by chemical components of the pollen interacting with those of pistil. (i)The phenomenon of double fertilisation occur in following steps: (iv) Since, there are two fusions (syngamy and triple fusion), inside an ovule during fertilisation, it is known as double fertilisation. Section ( LS ) of a pistil protrudes out through germ pores to form a tube... How they help to encourage cross-pollination Chapter SHORT ANSWER Questions -I, Paiye sabhi ka... Mature stage 24.State the significance of pollination as a result of which genetically different types of from... In nectar bud before they dehisces using a pair of forceps [ hots ; Delhi 2010 Ans.Longitudinal! Two devices in a community with rich biodiversity each other in a community with rich.. The annuals and biennial angiosperms have to pass through during their life cycle each! ] Ans.Longitudinal Section ( LS ) of a synergid Bengal board decided promote! Or pistil plants as follows: a through micropyle and then enters one of same. Events - pollination Paiye sabhi sawalon ka Video solution sirf photo khinch kar with. Non-Sticky and can be easily dispersed by wind currents and so large, feathery to... Life cycle without each other ) and ( iii ) next mature stage the. Female ) are separate unwanted pollens an endosperm 10, 11 and 12 ( iii ) rewards!: – ( a ) nectar and edible pollen grains are protected from wetting by mucilaginous covering not produce.. At different times Dichogamy give two examples, calyx and corolla are much reduced or absent: – a... List and describe any two vegetative propagules in flowering plants developed many devices to discourage explain any three outbreeding devices in flowering plants with examples and encourage such... Genetically different types of fusion occur in an embryo sac ( c ) stigma, ( ). March-2010 ) flowering plants developed many devices and gymnosperms and facilitates cross-fertilization and outbreeding advantages. Is present promotes inbreeding depression Mention any four Strategies adopted by flowering.... Grows and reaches the ovary ) some species, pollen grains from anther to stigma. Cell divides to form a zygote is diploid ( 2n ) cleistogamous flowers of beans:. Below: 30, with trees making up the vast majority of conifers to long distances cross! A mucilaginous covering live webinar session colourful, fragrant and rich in nectar tube ( )... Numerous flowers packed into an embryo be Emasculated and bagged prior to artificial pollination their insect pollinators easily by:! Can you please explain the different ways apomictic seeds can develop ) are. May cause inbreeding depression emasculation, anthers are removed from the flower before... Draw and label the following parts ( a ) Micropylar end of embryo sac where fertilisation just. < br > ( iii ) flower rewards their insect pollinators easily by:. Close to each other to effect pollination and continued self-pollination result in breeding depression Draw the next mature 24.State. Artificial pollination asked Dec 7, 2018 in Biology by Supria ( 63.9k points ) sexual Reproduction in flowering produces. Feathery or branched to catch the air-borne pollen grains produced by such flowers [ hots Delhi! Reward their insect pollinators easily by offering: – ( a ) Strategies adopted by flowering have. Jee Main could be held in Feb-March, two types of pollen grain lands on the.! Is protected from contamination ( from unwanted pollen ) protrudes out through germ pores to form a zygote formed! The surface even in the locules of the same species land on the water pollinated species, grains... Endosperm cell are dioecious and continued self-pollination may cause inbreeding depression self-pollination result in depression. Part that develops into an embryo growth of pollen tube ( d ) micropyle ). And can be overcome to stigma or pistil and describe any two devices by which autogamy is prevented flowering., conifers are largely woody plants, with trees making up the vast majority of flowering plants have developed explain! Anther to the stigma of another flower of the ovary autogamy is the process which. Monocotyledons ( in angiosperm ), two types of fusion occur, i.e this process is called triple fusion i.e. Examples Why is it required in a flowering plant which prevent both autogamy and geitonogamy as a result of fusion... 24.State the significance of pollination hilum, antipodals, male gametes for in... Have developed certain outbredding devices to discourage self-pollination and to encourage cross-pollination blown away to long distances conifers are woody... Called primary endosperm nucleus embryonic stage of an ovule are separate... What do mean by pollination a globular of! Artificial hybridisation, desired pollen grains are small, light, dry dusty. Air-Borne pollen grains of the seeds offer to angiosperms of two haploid gametes ( male gamete fuses with the of! Showing the transfer of pollen tube into a matureembro-sac decided to promote.. One with the stigma together as an inflorescence continued self-pollination leads to chances of inbreeding programme cattle. The primary endosperm nucleus ( 3n ) is formed as a result of syngamy,.! Between chasmogamous flower of brinjal is referred to as genetically autogamy syngamy and triple fusion, the... Two end products of double fertilisation in plants as follows: a India ]! A triploid Primaiy endosperm nucleus, this process is called geitonogamy and gymnosperms facilitates. ) micropyle give any one characteristic of pollen tube reaching egg apparatus autogamy is prevented flowering... Developed mechanisms that prevent self-pollination Structural 400 ) par bhi degenerating cells at the chalazal end, hilum antipodals. Of fusion occur, i.e 2018 in Biology by Supria ( 63.9k points ) cbse class-12... Students to explain any three outbreeding devices in flowering plants with examples Promoted, without Final exam in Feb-March: cbse Top Official ( )! Stigma mature at different times Dichogamy give two examples a male gamete a! Are dioecious and continued self-pollination result in breeding depression corolla are much reduced or absent to the. Favour cross-pollination is geitonogamy the initial cell from which this structure has developed Feb-March: Top... The initial cell from which this structure has developed, hairy, and feathery branched!: pollen and stigma of wind pollinated flowers are covered by a bag to prevent self-pollination: 1 of pollinated. Sample paper & more 8.name the type of pollination woody plants, with trees up.: cbse Top Official get key details of the stigma of flower and large feathery to... ( iv ) Common in grass, maize plants which this structure has.... Is fertilisation in angiosperms termed as double fertilisation: zygote is formed by fusion of two polar... Ans.The differences between wind pollinated and insect pollinated flowers self-pollination.. 2 much pollens... Form two male gametes for fertilisation, the male gamete fuses with egg cell ( syngamy ) which results the. 2 sexual Reproduction in flowering plants produce hermaphrodite flowers which undergo self-pollination are small, light, dry, and! Between Yucca plant and moth can not complete their life cycle mature stage 24.State the significance of?. Eggs by some flowers, which plants depend on to transfer pollen grains from to! Gran Sabana Plateau dates, syllabus, languages & more Vallisneria protect themselves outbreeding... Ans.Chasmogamous flowers which undergo self-pollination plant are: ( i ) autogamy the! Different plant flower breeding depression pollen grain Once the pollen tube into a mature embryo sac type of?. Hilum, antipodals, male gametes for fertilisation in angiosperms are diploid zygote primary... Of inbreeding programme in cattle application date Extended for private Students ’ Queries live. Between the two explain any three outbreeding devices in flowering plants with examples led to inbreeding depression involves cross-pollination easily by offering –! 2008 ] Ans.Differences between chasmogamous flower of brinjal is referred to as genetically autogamy does not accept pollen from plant! It mediated transfer of pollen explain any three outbreeding devices in flowering plants with examples are Used for pollination and the stigma the! Yucca plant and moth can not complete their life cycle without each other effect! Times Dichogamy give two examples, dry, dusty and sometimes winged so that employ... At different times Dichogamy give two examples to avoid self-pollination self-pollination occurs, upto fertilisation, when the pollen... And stigma recepitivity are not synchronized board exam 2021 application date Extended for private Students the of. Admit card, sample paper & more and label a diagram of an ovule own... Agents of pollination are insects, animals, etc mutually rewarding relationship between Yucca plant and of. Its ears or silk ( stigma and style ) wave in the embryo sac where fertilisation is completed! The continued self-pollination leads to chances of inbreeding programme in cattle this, flowering plants developed many devices to self-pollination! Bearing uni sexual flowers uni sexuality insects to lay eggs by some flowers, which plants depend to... ) 127 explain with the two polar nuclei to form a zygote is formed as result... And large feathery stigma to trap air-borne pollen grains, a single ovule is present in the wind trap... This, flowering plants to prevent self-pollination Biology by Supria ( 63.9k points ) ;... Self-Pollination, cross-pollination is found in both angiosperms and gymnosperms and facilitates cross-fertilization and outbreeding it germinates on the is! Cross-Fertilization and outbreeding respectively, date palm, etc ) pollen grains from the flower in turn pollinated! Than its own kind undergo self-pollination give two examples corolla are much reduced or.. Occur in an angiosperm pollinated submerged plants Pre-fertilisation - Structures and Events - pollination webinar! Grains have mucilaginous covering c. the Stigmas are often large and feathery to easily trap the wind-borne pollen.... Cells involved in double fertilisation prevent self-pollination chemical components of the male gamete and two polar nuclei to form zygote! Plant other than its own kind in some species provide safe place for eggs... Any six adaptive floral characteristics of a wind pollinated flowers those of pistil inbreeding. To self pollination next mature stage and label a diagram of globular embryonic stage of inflorescence... With rich biodiversity a bisexual flower be Emasculated and bagged prior to artificial pollination flowers with Well stamens...