Answer: (a) Contrivances for cross-pollination: [Out breeding devices] The following contrivances ensure cross-pollination: 1. Balbharati solutions for Biology 12th Standard HSC Maharashtra State Board chapter 1 (Reproduction in Lower and Higher Plants) include all questions with solution and detail explanation. Pollen-pistil Interaction 6. … Ans. Books. Gynoecium of a flower may be apocarpous or syncarpous. (b) What is apomixis? This will clear students doubts about any question and improve application skills while preparing for board exams. This is known as outbreeding. 3 marks Q.
a. Artificial Hybridisation 7. Q.55. Each pollen grain grows and provides two male gametes for fertilisation of an ovule. (a) Strategies adopted by flowering plants to prevent self-pollination: 1.
(iii) Dichogamy is of two types, viz., protandry and protogyny. Q:-What is triple fusion? Q. 3 Sol. 20. Explain with the help of an example each. Make a list of any three outbreeding devices that flowering plants have developed. ... As this involves the fusion of three haploid nuclei it is termed triple fusion. 29. Ask your question. As both types of gametes are non-motile, they have to be brought together for fertilisation to occur.
1. Question 1. (a)Explain the process of megasporogenesis. it has made plants outbreeders and this maintain vigour and vitality of the race. Draw a labeled diagram of embryosac in angiosperms.Name the cell that develop into the embryosac and explain how this cell leads to the formationof Embryosac. This prevents self-pollination. variations appear due to outbreeding provide adaptability to the changes in … Also mention the role played by the various cells of theembryosac. Join now. 1. Make a list of an y three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination . 3 13 . Why do hermaphrodite angiosperms develop outbreeding devices? Briefly describe its structure. Ans. The plants may be monoecious (bearing both male and female flowers, e.g., Maize) or dioecious (bearing male and female flowers on different plants, e.g., Mulberry, Papaya). outbreeding devices class 12th | part 8- reproduction in lower and higher plants in this video lecture I have explain about different outbreeding devices in plants. First of all what are outbreeding devices n why r they necessary-Devices that discourage SELF-POLLINATION & encourage CROSS-POLLINATION are known as outbreeding devices. If implementation of better techniques and new strategies are required to provide more efficient Dichogamy:
(i) Maturation of anther (stamen) and stigma (carpel) at different times is called dichogamy. Outbreeding Devices or Contrivances to Ensure Cross Pollination: (i) Dicliny (Uni-sexuality): Flowers are unisexual so that self pollination is not possible. There are 4 types of outbreeding devices-1.) 16.
(ii) Dichogamy favours cross pollination as it stands as a barrier to self pollination. Describe the structure of its microsporangium. Q.3. Self-pollination is common and more likely to happen in the case of hermaphrodite flowers but a successive series of self-pollination affects negatively and causes inbreeding depression. Log in. 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. (ii) Dichogamy: Q.20.If implementation of better techniques and new strategies are required to (a) List the three states the annuals and biennial angiosperms have to pass through during their life cycle. Explain the importance of each. vikas6748 14.03.2019 Biology Secondary School +5 pts. Explain with the help of suitable examples why is it required in a community with rich biodiversity. Give a brief account of oogenesis. (b)Name any three outbreeding devices. ... Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. Types of Pollination: The transfer of pollen grains from the opened anther of the stamen to the receptive stigma of the carpel/pistil is called pollination. _____ In some species , pollen is released before the stigma becomes receptive or stigma becomes receptive much before the release of pollen . OR Why are angiosperm anthers called dithecous ? Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination? Advantages of sexual incompatibility: it prevents self pollination. After implantation interdigitation of maternal and foetal tissues takes place. This also results in homozygous genes. 17 Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. Give any three advantages of sexual incompatibility. (3) OR. [1+1+1=3] 13. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. Sol. Explain any two such devices with the help of examples. asked Feb 29 in Biology by KumkumBharti (53.8k points) class-12; 0 votes. 1 answer. Summary Pollination We know that that the male and female gametes in flowering plants are produced in the pollen grain and embryo sac, respectively. Mechanisms that prevent self-pollination Structural. Explain the various causes that have brought about this difference. Three outbreeding devices in plants : (i) Difference in maturation time of pollen and stigma or pollen release and stigma receptivity are not synchronised. Q:-With a neat, labelled diagram, describe the parts of a typical angiosperm ovule. Q.56. 21. Identify the tissues involved and justify their role. (ii) Anther and stigma are placed at different position so that the pollen cannot come in contact with the stigma of … 18 Why are angiosperm anthers called dithecous ? Describe the structure of its microsporangium. Both, autogamy and geitonogamy are prevented in (a) papaya. ADVERTISEMENTS: In this article we will discuss about the types and agents of pollination. . [All India 2014] Ans.The three outbreeding devices that flowering plants have developed, so as to encourage cross-pollination are: Kerala State Board New Syllabus Plus Two Botany Chapter Wise Previous Questions and Answers Chapter 2 Sexual Reproduction in Flowering Plants.. Kerala Plus Two Botany Chapter Wise Previous Questions Chapter 2 Sexual Reproduction in Flowering Plants. Explain the devices that the plants have developed to prevent this. Thus plants are adapted to promote cross-pollination. Dicliny: It is the condition where one of the two sexes is absent in the flower and flower becomes unisexual male or female (didhnous). Physics. 19. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. (a) Explain any four outbreeding devices that prevent autogamy. asked Oct 24, 2018 in Biology by Richa (60.6k points) sexual reproduction in … [1+1+1=3] 12. (b) List and describe any two vegetative propagules in flowering plants. Label any four parts. Outbreeding Devices: To avoid inbreeding depression and promote outbreeding, the plants have evolved certain devices/contrivances such as: By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious or recessive traits resulting from incestuous sexual relationships and consanguinity. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. In order to avoid self-pollination,cross-pollination is encouraged in plants as follows : a. Out breeding devices present in flowering plant 1. Not surprisingly, many species of plants have developed mechanisms that prevent self-pollination. Dichogamy: Pollen and stigma of the flower mature at different times to avoid self-pollination.. 3. Solution : Outbreeding devices in Angiospermic plants. Find an answer to your question explain three outbreeding devices 1. 15.Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross pollination. 44. Herkogamy: Flowers possess some mechanical barrier on their stigmatic surface to avoid self-pollination.. 2. Compare the two ecological pyramids of biomass given below and explain the situations in which this is … Compare the two ecological pyramids of biomass given below and explain the situations in which this is possible. Identify the tissues involved and justify their role. Out breeding devices are used to prevent self pollination, which is the main cause of low variety and quality of the plant product and thereby encourage cross pollination to occur between plants. 20. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. Explain three outbreeding devices. In some species, pollen release and stigma recepitivity are not synchronized. Q:-Differentiate between a zoospore and a zygote. (i) Time of pollen release and stigma receptivity are different (not synchronised). Describe the structure of its Microsporangium. 2 See answers AionAbhishek AionAbhishek Ahoy!!! State what is apomixis. Join now. Explain three outbreeding devices. and explain how they help to encourage cross-pollination. Q.57. OR Show diagrammatically the stages of embryonic development from … Outbreeding devices : Majority of flowering plants produces hermaphrodite flowers which undergo self-pollination. List the adaptive features of water pollinated flowers like Vallisneria. They r necessary bcuz continued SELF-POLLINATION in flowers causes a downfall in the quality and variety of the products. Outbreeding Devices 5. 3 12 . 3 marks Q. Where and how does it take place? Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. NEET Botany Sexual Reproduction in Flowering Plants questions & solutions with PDF and difficulty level Depending upon […] Why angiosperm anthers are called dithecous? Q:-With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte. Make a list of an y three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination . Some outbreeding devices used are :-1. Outbreeding Devices. 3 marks OR Why are angiosperm anthers called dithecous? Outbreeding and inbreeding strategies recognized in this study are associated with functional groups and isolation of the herbaceous-shrubby communities in the Gran Sabana Plateau. Continuous self-pollination results in inbreeding depression. Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. 10. Log in. 45. Ans. Describe any three potential applications of genetically modified plants. 19 Draw a diagram of a male gametophyte of an angiosperm. What is self incompatibility? Q:-What is oogenesis? Answered Explain three outbreeding devices 1 See answer Explain any three advantages the seeds offer to angiosperms. 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