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Question
Explain the post-pollination events leading to seed production in angiosperms.
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Solution
Pollination is the process of transfer of pollen grains from anther to stigma.
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When the pollen grains fall on the stigma, the pollen tube enters one of the synergids and releases two male gametes.
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One of the male gametes moves towards the egg cell and fuses with it to form zygote.
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The other male gamete fuses with the two polar nuclei and forms the primary endosperm nucleus. This is termed as triple fusion.
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After the triple fusion, the central cell becomes the primary endosperm cell (PEC).
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The primary endosperm nucleus gives rise to endosperm, while the zygote develops into embryo.
- Seeds are the fertilised ovules that are developed inside a fruit.
- The integuments of ovules harden to form the seed coat, and the micropyle facilitates the entry of oxygen and water into the seed.
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RELATED QUESTIONS
Lever mechanism of pollination is observed in
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Heterostyly as a contrivance for cross-pollination is found in ______.
Complete the following table:
| Sr. | Type of pollination | Agent | Kind of flower | Examples |
| (i) | ______ | Wind | ______ | Maize |
| (ii) | Chiropterophily | ______ | Dull colour, with strong fragrance, abundant nectar | Adansonia |
| (iii) | Entamophily | Insects | ______ | Rose/Jasmine |
| (iv) | Ornithophily | ______ | Brightly coloured, large and showy. They secrete profuse, dilute n ectar | ______ |
