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प्रश्न
Explain the events upto double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm.
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उत्तर
The events which occur during double fertilization are:
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Two male gametes are released by the pollen tube into the cytoplasm of synergid.
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One of these male gametes moves towards the egg cell and fuses with the nucleus. This process is called syngamy and results in the formation of a diploid cell, zygote,which eventually forms an embryo.
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The other male gamete moves towards the polar nuclei located in the central cell and fuses with them to form a triploid primary endosperm nucleus (PEN). This process is called triple fusion.
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Since two types of fusion, syngamy and triple fusion, take place here, the phenomenon is called double fertilisation.
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संबंधित प्रश्न
Sketch and label stages in the development of the angiospermic female gametophyte from the functional megaspore.
A typical flower has ______ different kinds of whorl.
Pollen grains are well preserved as fossils because of the presence of ______
In a fertilized ovule, n, 2n, and 3n conditions occur respectively in ______
Angiosperms have dominated the land flora primarily because of their ______.
What is the similarity between gymnosperms and angiosperms?
Match List I with List II:
| List I (Types of Stamens) |
List II (Example) |
||
| A. | Monoadelphous | I. | Citrus |
| B. | Diadelphous | II. | Pea |
| C. | Polyadelphous | III. | Lily |
| D. | Epiphyllous | IV. | China-rose |
Choose the correct answer from the options given below:
Axile placentation is observed in ______.
What is the floral envelope called when the calyx (sepals) and corolla (petals) cannot be differentiated from one another?
The male reproductive unit of a flower, the androecium, is made up of individual members called ______.
