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प्रश्न
Explain the post-pollination events leading to seed production in angiosperms.
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उत्तर
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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संबंधित प्रश्न
A flower of tomato plant following the process of sexual reproduction produces 200 viable seeds.
Answer the following questions giving reasons :
(a) What would have been the minimum number of ovules present in pre-pollinated pistil ?
(b) How many microscope mother cells would minimally be required to produce requisite number of pollen grains ?
(c) How many pollen grains must have minimally pollinated the carple ?
(d) How many male gametes would have used to produce these 200 viable seeds ?
(e) How many megaspore mother cells were required in this process ?
What is meant by emasculation?
Add a note on pollination mechanism in Salvia.
Which one of the following is one of the characteristics of self-pollinated flowers?
Fill in the blanks with suitable words.
_______ is a water-pollinated flower.
Give four adaptations shown by flowers pollinated by wind.
Describe the Advantages and Disadvantages of self-pollination to the Plant.
Male and female flowers are present on different plants (dioecious) to ensure xenogamy, in ______.
Which of these is a condition that makes flowers invariably autogamous?
Give any four floral adaptations for chiropterophily.
