Q:-Differentiate between a zoospore and a zygote. (i) Time of pollen release and stigma receptivity are different (not synchronised). Pollen-pistil Interaction 6. variations appear due to outbreeding provide adaptability to the changes in … After implantation interdigitation of maternal and foetal tissues takes place. (b) What is apomixis? Compare the two ecological pyramids of biomass given below and explain the situations in which this is … [All India 2014] Ans.The three outbreeding devices that flowering plants have developed, so as to encourage cross-pollination are: Books. Outbreeding Devices or Contrivances to Ensure Cross Pollination: (i) Dicliny (Uni-sexuality): Flowers are unisexual so that self pollination is not possible. OR Show diagrammatically the stages of embryonic development from … This is known as outbreeding. Log in. NEET Botany Sexual Reproduction in Flowering Plants questions & solutions with PDF and difficulty level This also results in homozygous genes. 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. (a) Strategies adopted by flowering plants to prevent self-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. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination? (ii) Anther and stigma are placed at different position so that the pollen cannot come in contact with the stigma of … Ans. State what is apomixis. Describe the structure of its microsporangium. 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. Q.3. Explain three outbreeding devices. ... As this involves the fusion of three haploid nuclei it is termed triple fusion. This prevents self-pollination. After implantation interdigitation of maternal and foetal tissues takes place.
(ii) Dichogamy favours cross pollination as it stands as a barrier to self pollination. asked Oct 24, 2018 in Biology by Richa (60.6k points) sexual reproduction in … 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. Identify the tissues involved and justify their role. 10. . Give any three advantages of sexual incompatibility. 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. … Continuous self-pollination results in inbreeding depression. ADVERTISEMENTS: In this article we will discuss about the types and agents of pollination. Describe any three potential applications of genetically modified plants. Summary Pollination We know that that the male and female gametes in flowering plants are produced in the pollen grain and embryo sac, respectively. Log in. Physics. Out breeding devices present in flowering plant 1.
1. 1. 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. (a)Explain the process of megasporogenesis. Label any four parts. Answer: (a) Contrivances for cross-pollination: [Out breeding devices] The following contrivances ensure cross-pollination: 1. Mechanisms that prevent self-pollination Structural. Answered Explain three outbreeding devices 1 See answer Identify the tissues involved and justify their role. 3 marks Q. If implementation of better techniques and new strategies are required to provide more efficient Describe the structure of its Microsporangium. Briefly describe its structure. _____ In some species , pollen is released before the stigma becomes receptive or stigma becomes receptive much before the release of pollen . They r necessary bcuz continued SELF-POLLINATION in flowers causes a downfall in the quality and variety of the products. Q.20.If implementation of better techniques and new strategies are required to Explain the various causes that have brought about this difference. (b) List and describe any two vegetative propagules in flowering plants. 3 Sol. Dichogamy: Pollen and stigma of the flower mature at different times to avoid self-pollination.. 3. Ans. Make a list of any three outbreeding devices that flowering plants have developed. OR Why are angiosperm anthers called dithecous ? Why do hermaphrodite angiosperms develop outbreeding devices? 2 See answers AionAbhishek AionAbhishek Ahoy!!! (b)Name any three outbreeding devices. Explain any three advantages the seeds offer to angiosperms. Ans. Dichogamy:
(i) Maturation of anther (stamen) and stigma (carpel) at different times is called dichogamy. Q:-With a neat, labelled diagram, describe the parts of a typical angiosperm ovule. 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. Sol. Question 1.
a. 1 answer. 3 13 . Explain three outbreeding devices. Outbreeding devices : Majority of flowering plants produces hermaphrodite flowers which undergo self-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). Also mention the role played by the various cells of theembryosac. Make a list of an y three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination . Explain the devices that the plants have developed to prevent this. Three outbreeding devices in plants : (i) Difference in maturation time of pollen and stigma or pollen release and stigma receptivity are not synchronised. 15.Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross pollination. Make a list of an y three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination . asked Feb 29 in Biology by KumkumBharti (53.8k points) class-12; 0 votes. 3 12 . Thus plants are adapted to promote cross-pollination. vikas6748 14.03.2019 Biology Secondary School +5 pts. Describe the structure of its microsporangium. Q. 45. Both, autogamy and geitonogamy are prevented in (a) papaya. 3 marks Q. Explain with the help of an example each. Join now. In order to avoid self-pollination,cross-pollination is encouraged in plants as follows : a. Explain the importance of each. (a) List the three states the annuals and biennial angiosperms have to pass through during their life cycle. There are 4 types of outbreeding devices-1.) 18 Why are angiosperm anthers called dithecous ? Describe the structure of its microsporangium. Q.55. [1+1+1=3] 13. 29. Each pollen grain grows and provides two male gametes for fertilisation of an ovule. 20. 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. Explain with the help of suitable examples why is it required in a community with rich biodiversity. Join now. Q:-What is triple fusion? List the adaptive features of water pollinated flowers like Vallisneria. (3) OR. (a) Explain any four outbreeding devices that prevent autogamy. Q.56. Artificial Hybridisation 7. Make a list of any three out breeding devices that flowering plants have developed and explain how they help to encourage cross pollination. 44. Depending upon […] Find an answer to your question explain three outbreeding devices 1. it has made plants outbreeders and this maintain vigour and vitality of the race. Why angiosperm anthers are called dithecous? Ask your question. Some outbreeding devices used are :-1. What is self incompatibility? Outbreeding Devices 5.
(iii) Dichogamy is of two types, viz., protandry and protogyny. This will clear students doubts about any question and improve application skills while preparing for board exams. 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. and explain how they help to encourage cross-pollination. 16. Q:-With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte. Q.57. Outbreeding Devices: To avoid inbreeding depression and promote outbreeding, the plants have evolved certain devices/contrivances such as: 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. ... Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. As both types of gametes are non-motile, they have to be brought together for fertilisation to occur. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. Explain any two such devices with the help of examples. 21. Herkogamy: Flowers possess some mechanical barrier on their stigmatic surface to avoid self-pollination.. 2. Not surprisingly, many species of plants have developed mechanisms that prevent self-pollination. Outbreeding Devices. 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. Gynoecium of a flower may be apocarpous or syncarpous. In some species, pollen release and stigma recepitivity are not synchronized. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. 19 Draw a diagram of a male gametophyte of an angiosperm. Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. 3 marks 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. 17 Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination. Give a brief account of oogenesis. Compare the two ecological pyramids of biomass given below and explain the situations in which this is possible. [1+1+1=3] 12. Where and how does it take place? 20. 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