Advertisements
Advertisements
प्रश्न
Where and how does triple fusion take place?
उत्तर
Since two types of fusions, syngamy and triple fusion, take place in an embryo sac the phenomenon is termed double fertilisation, an event unique to flowering plants. The central cell after triple fusion becomes the primary endosperm cell (PEC) and develops into the endosperm, while the zygote develops into an embryo.
APPEARS IN
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.
Read the following statement and answer the questions that follow :
"A guava fruit has 200 viable seeds."
(a) What are viable seeds?
(b) Write the total number of :
(i) Pollen grains (ii) Gametes
in producing 200 viable guava seeds.
c) Prepare a flow-chart to depict the post-pollination events leading to viable-seed production in a flowering plant.
Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy.
Explain the following term:
Elephophily
What happens to the following after fertilization?
Petals
What happens to the following after fertilization?
Stamens
What are the advantages of the following in the flower to the plant concerned?
Protruding and easily movable anthers
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:
What is the function of the part labelled '4'?
Given ahead is a diagrammatic representation of the process of fertilization. Study the same and then answer the question that follows:
What happens to
i) Ovary
ii) Ovule after fertilisation
What is ‘double fertilization’? Describe it with the help of a neat and well-labeled diagram. Give its importance.
Expand the following abbreviation IW.
Name the scientists who have contributed to the following:
Discovered double fertilization.
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?
Assertion: Sporopollenin preserves pollen in fossil deposits
Reason: Sporopollenin is resistant to physical and biological decomposition
Which of the following represent megagametophyte
In Haplopappus gracilis, number of chromosomes in cells of nucellus is 4. What will be the chromosome number in Primary endosperm cell?
Transmitting tissue is found in
Define triple fusion.
Write a short note on Pollen kitt.
Write a short note on Heterostyly.
Explain the development of a Dicot embryo
By which of the following the megasporangium proper of an angiosperm ovule is represented?
Due to which of the following reasons the pollen tube usually grows down towards the egg?
In angiosperms, for formation of which of the following triple fusion is necessary?
Identify the function of filiform apparatus.
If the cells of the nucellus in the angiosperm ovule contain 24 chromosomes, then ____________ chromosomes will be present in the endosperm of a self-pollinated flower.
Double fertilization is fusion of ______.
The female gametophyte of a typical dicot at the time of fertilisation is ______.
Fusion of one of the male gametes with egg nucleus is referred to as ______.
Ovules fall off after fertilization.
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?
What is Siphonogamy?
