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प्रश्न
What is triple fusion?
उत्तर
After entering one of the synergids, the pollen tube releases the two male gametes into the cytoplasm of the synergid. One of the male gametes moves towards the egg cell and fuses with its nucleus, thus completing the syngamy. This results in the formation of a diploid cell, the zygote. The other male gamete moves towards the two polar nuclei located in the central cell and fuses with them to produce a triploid primary endosperm nucleus (PEN). As this involves the fusion of three haploid nuclei, it is termed triple fusion.
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संबंधित प्रश्न
What is double fertilisation? Describe the process in brief.
Why do you think the zygote is dormant for sometime in a fertilised ovule?
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.
Explain the following term:
Elephophily
What happens to the following after fertilization?
Petals
Given ahead is a diagrammatic sketch of the sectional view of a germinating pollen grain. Study the same and then answer the question that follows:
Name the parts labelled 1, 2, 3, 4 and 5.
Given ahead is a diagrammatic sketch of the sectional view of a germinating pollen grain. Study the same and then answer the question that follows:
Where does the germination of the pollen grain take place and how?
Given ahead is a diagrammatic representation of the process of fertilization. Study the same and then answer the question that follows:
Name the parts labelled 1, 2, 3, 4, 5 and 6.
What is ‘double fertilization’? Describe it with the help of a neat and well-labeled diagram. Give its importance.
What is the significance of the dispersal of seeds? Give any two points.
Define fertilization.
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
The question has four options. Choose the correct answer:
The study of fruits is known as
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?
Give any four points of significance of double fertilization.
The seed is a fertilized _______.
Match the following
| I) | External fertilization | i) | pollen grain |
| II) | Androecium | ii) | anther wall |
|
III) |
Male gametophyte | iii) | algae |
| IV) | Primary parietal layer | iv) | stamens |
Transmitting tissue is found in
In majority of plants pollen is liberated at
Name the cell which divides to form male nuclei.
Write a short note on Pollen kitt.
Write a short note on Heterostyly.
Explain the development of a Dicot embryo
Which of the following is the CORRECT sequence of events during double fertilization in Angiosperms?
In double fertilization, the first male gamete fuses with the egg and the second male gan1ete fuses with which of the following?
The success of seed plants on land is mainly due to ______.
Due to which of the following reasons the pollen tube usually grows down towards the egg?
Identify the function of filiform apparatus.
If the cells of the nucellus in the angiosperm ovule contain 24 chromosomes, then ____________ chromosomes will be present in the endosperm of a self-pollinated flower.
Through which route the pollen tube can enter the ovule?
Double fertilization was first discovered by Nawaschin (1898) in ______.
Double fertilization is characteristic of ______.
Ovules fall off after fertilization.
Name the part of gynoecium that determines the compatible nature of pollen.
Which are the three cells found in a pollen grain when it is shed at the three celled stage?
Select the option that shows the correctly identified 'U', 'X', 'Y' and 'Z' in a developing dicot embryo.
What is Siphonogamy?
Give a term for the following:
Fusion of male gamete and secondary nucleus in angiosperms.
