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प्रश्न
Give a concise account of the steps involved in the fertilization of an angiosperm plant.
उत्तर
Steps involved in fertilization of angiospermic plant:
- Germination of pollen grain on stigma.
- Formation of pollen tube in stigma.
- Growth of pollen tube inside the style.
- The direction of the pollen tube towards the micropyle of the ovule.
- Entry of pollen tube into the synergid of embryo sac.
- Discharge of male gametes from the pollen tube.
- Fusion of male gamete with egg cell (syngamy)
- Fusion of second male gamete with polar nuclei (triple fusion/double)
संबंधित प्रश्न
What is double fertilisation? Describe the process in brief.
Why do you think the zygote is dormant for sometime in a fertilised ovule?
Differentiate between outbreeding and outcrossing.
(a) Explain the events after pollination leading to the formation of a seed in angiosperms.
(b) Mention the ploidy levels of the cells of different parts of an albuminous seed.
Given ahead is a diagrammatic representation of the process of fertilization. Study the same and then answer the question that follows:
What part does the stigma play in the process of fertilisation?
What is the significance of the dispersal of seeds? Give any two points.
Even though each pollen grain has 2 male gametes, why at least 20 pollen grains are required to fertilize 20 ovules in a particular carpel?
Give any four points of significance of double fertilization.
Syngamy results in the formation of ______.
Male gametes in angiosperms are formed by the division of ______.
In Haplopappus gracilis, number of chromosomes in cells of nucellus is 4. What will be the chromosome number in Primary endosperm cell?
Write a short note on Heterostyly.
Identify the function of filiform apparatus.
Through which route the pollen tube can enter the ovule?
Name the part of gynoecium that determines the compatible nature of pollen.
In the diagram given below, show the path of a pollen tube from the pollen on the stigma into the embryo sac. Name the components of egg apparatus.
Can an unfertilised, apomictic embryo sac give rise to a diploid embryo? If yes, then how?
Which are the three cells found in a pollen grain when it is shed at the three celled stage?
What is Siphonogamy?
