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प्रश्न
Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy.
उत्तर
Two devices which prevent both autogamy and geitonogamy in flowering plants are:
1) In some species, pollen release and stigma receptivity are not synchronised. In this case, either the pollen is released before the stigma becomes receptive or the stigma becomes receptive much before the release of the pollen.
2) In another method, the anther and stigma are placed at the different position so that the pollen does not come in contact with the stigma of the same flower.
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संबंधित प्रश्न
Read the following statement and answer the questions that follow :
"A guava fruit has 200 viable seeds."
(a) What are viable seeds?
(b) Write the total number of :
(i) Pollen grains (ii) Gametes
in producing 200 viable guava seeds.
c) Prepare a flow-chart to depict the post-pollination events leading to viable-seed production in a flowering plant.
Fill in the blanks with suitable words.
Transference of pollen grains from anthers to stigma of the same flower is called ________.
Name of the part of the ovary which gives rise to:
Seed ______
Give one word/term for the following:
When pollen grains of a flower reach the stigma of the same flower.
What happens to the following after fertilization?
Petals
Given ahead is a diagrammatic representation of the process of fertilization. Study the same and then answer the question that follows:
What part does the stigma play in the process of fertilisation?
What is ‘double fertilization’? Describe it with the help of a neat and well-labeled diagram. Give its importance.
What is ‘double fertilization’? Describe it with the help of a neat and well-labeled diagram. Give its importance.
Name the scientists who have contributed to the following:
Discovered double fertilization.
Explain double fertilization and its significance.
The question has four options. Choose the correct answer:
One male gamete fuses with the egg and forms a diploid zygote. This process is called
Even though each pollen grain has 2 male gametes, why at least 20 pollen grains are required to fertilize 20 ovules in a particular carpel?
Syngamy results in the formation of ______.
Caruncle develops from
In angiosperms, for formation of which of the following triple fusion is necessary?
Following diagram represents double fertilization. Identify the INCORRECT label.
In a breeding experiment, the selected male parent is diploid and the female parent is tetraploid. What will be the ploidy level of the endosperm that will develop after double fertilisation?
Can an unfertilised, apomictic embryo sac give rise to a diploid embryo? If yes, then how?
Identity the part of embryo sac which takes part in formation of primary endosperm nucleus during fertlisation
