Скачать или смотреть Fertilization in Plants || How does fertilisation takes place in Plants ? || Essential Science ||

Fertilization in Plants || How does fertilization takes place in Plants ? || Essential Science ||

Fertilization
Fusion of male gamete & female gamete to form a zygote.

How does fertilization take place?
1. After pollination, the pollen grains germinate in response to the sugary fluid secreted by the mature stigma.
2. A pollen tube grows out from each pollen grain.
3. The cytoplasm and the two nuclei (pollen tube nucleus and generative nucleus) of each pollen grain pass into the pollen tube. The growth of the pollen tube is controlled by the pollen tube nucleus.
4. As the pollen tube grows, it secretes enzymes to digest the surrounding tissue of the stigma and style. Thus, the pollen tube penetrates right through the style as it grows.
5. The pollen tube enters the ovule usually through an opening in the ovule wall called the micropyle.
6. Along the way, the generative nucleus divides to form two male gametes. The pollen tube nucleus soon disintegrates.
7. Within the ovule, the tip of the pollen tube absorbs sap and bursts, releasing the two male gametes.
8. One male gamete fuses with the ovum to form the zygote. This is fertilisation. The other male gamete fuses with the definitive nucleus to form the endosperm nucleus.
9. The zygote will divide and develop into the embryo in the seed. The endosperm nucleus will divide and give rise to the food storage tissue called the endosperm. After fertilisation, the ovule develops into a seed and the ovary into a fruit.






Fate of Flower Parts after fertilization
• Ovary: becomes fruit
• Ovary wall: becomes fruit wall
• Ovule: becomes seed
• Integument /ovule wall: becomes seed coat
• Fertilized egg: becomes embryo surrounded by endosperm which supplies food to it

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