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प्रश्न
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.
उत्तर
Following compatible pollination, the pollen grain germinates on the stigma to produce a pollen tube through one of the germ pores. The contents of the pollen grain (2 mole nuclei) move into the pollen tube. Pollen tube grows through the tissues of the stigma and reaches the ovary. After reaching the ovary, pollen tube, enters the ovule through the micropyle and then enters the embryo sac by passing into one of the synergids through the filiform apparatus. It leads to the degeneration of that synergid.
The pollen tube breaks to release its contents (2 male nuclel). Out of the two male gametes one fuses with egg and the other fuses with central cell and fertilise.
Longitudinal section of a flower showing growth of pollen tube
The component cells of the egg-apparatus in an embryo sac include, two synergids one egg cell and the filiform apparatus.
A diagrammatic representation of the mature embryo sac
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संबंधित प्रश्न
'Formation of primary endosperm nucleus is called triple fusion'. Give reason
Double fertilization is reported in plants of both, castor and groundnut. However, the mature seeds of groundnut are non-albuminous and castor are albuminous. Explain the post fertilization events that are responsible for it.
Where and how does triple fusion take place?
Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy.
Given ahead is a diagrammatic sketch of the sectional view of a germinating pollen grain. Study the same and then answer the question that follows:
Where does the germination of the pollen grain take place and how?
Explain double fertilization and its significance.
Long Answer Question:
Draw a labeled diagram of the L.S. of anatropous ovule and list the components of the embryo sac and mention their fate after fertilization.
In majority of plants pollen is liberated at
Define triple fusion.
Give a concise account of the steps involved in the fertilization of an angiosperm plant.
Explain the development of a Dicot embryo
The success of seed plants on land is mainly due to ______.
By which of the following the megasporangium proper of an angiosperm ovule is represented?
What would be the number of chromosomes in the megaspore mother cell of the plant if an endosperm of an angiosperm has 24 chromosomes?
The female gametophyte of a typical dicot at the time of fertilisation is ______.
After fertilization, the seed coat of seeds develops from ______
Can an unfertilised, apomictic embryo sac give rise to a diploid embryo? If yes, then how?
In the figure given below label the following parts: male gametes, egg cell, polar nuclei, synergid and pollen tube
Name the following:
A diploid nucleus in central cell of embryo sac in plants.
Give a term for the following:
Fusion of male gamete and secondary nucleus in angiosperms.
