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प्रश्न
What is the function of the two male gametes produced by each pollen grain in angiosperms?
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 or oosphere 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).
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संबंधित प्रश्न
Double fertilization is reported in plants of both, castor and groundnut. However, the mature seeds of groundnut are non-albuminous and castor are albuminous. Explain the post fertilization events that are responsible for it.
Why do you think the zygote is dormant for sometime in a fertilised ovule?
Match the items in Column A with those in Column B.
|
Column A |
Column B |
|
(a) Generative nucleus |
(i) Pollen tube |
|
(b) Germ pore |
(ii) Endosperm nucleus |
|
(c) Exine |
(iii) Testa |
|
(d) Secondary nucleus |
(iv) Fertilization |
|
(e) Integument |
(v) Male nuclei |
|
(f) Egg nucleus |
(vi) Rough |
What happens to the following after fertilization?
Ovules
What happens to the following after fertilization?
Calyx
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?
What is a fruit?
Long Answer Question:
Draw a labeled diagram of the L.S. of anatropous ovule and list the components of the embryo sac and mention their fate after fertilization.
Describe the process of double fertilization in angiosperms and add a note on its significance.
In Haplopappus gracilis, number of chromosomes in cells of nucellus is 4. What will be the chromosome number in Primary endosperm cell?
The success of seed plants on land is mainly due to ______.
By which of the following the megasporangium proper of an angiosperm ovule is represented?
Double fertilization and triple fusion were discovered by ______.
Double fertilization is characteristic of ______.
The female gametophyte of a typical dicot at the time of fertilisation is ______.
The total number of nuclei involved in double fertilisation in angiospersm are ______.
In ______ sepal is seen on the fruit after fertilization.
Can an unfertilised, apomictic embryo sac give rise to a diploid embryo? If yes, then how?
In the figure given below label the following parts: male gametes, egg cell, polar nuclei, synergid and pollen tube
Select the option that shows the correctly identified 'U', 'X', 'Y' and 'Z' in a developing dicot embryo.
