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प्रश्न
What is polyembryony? How it can commercially exploited.
उत्तर
The occurrence of more than one embryo in a seed is called polyembryony.
- Embryos developed through polyembryony are found virus-free.
- The seedlings formed from nuclear tissue in citrus are found on better clones for orchards.
संबंधित प्रश्न
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.
Fill in the blanks with suitable words.
Transference of pollen grains from anthers to stigma of the same flower is called ________.
Match the items in Column A with those in Column B.
|
Column A |
Column B |
|
(a) Generative nucleus |
(i) Pollen tube |
|
(b) Germ pore |
(ii) Endosperm nucleus |
|
(c) Exine |
(iii) Testa |
|
(d) Secondary nucleus |
(iv) Fertilization |
|
(e) Integument |
(v) Male nuclei |
|
(f) Egg nucleus |
(vi) Rough |
What is the function of the pollen tube? Explain it with the help of a diagram.
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 is the function of the synergids?
Identify the incorrect pair
Syngamy results in the formation of ______.
Male gametes in angiosperms are formed by the division of ______.
Which of the following represent megagametophyte
Name the cell which divides to form male nuclei.
Explain the development of a Dicot embryo
Double fertilization is characteristic of ______.
Ovules fall off after fertilization.
Find out the CORRECT sequence of events taking place in pollen - pistil interaction.
- Pollen tube enters one of the synergids and bursts to release male gametes.
- Pollen tube enters the ovule through the micropyle of the ovary.
- The pollen tube grows through the stigmatic tissue and then style.
- Pistil recognizes the correct pollen and accepts it.
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 is the triploid tissue in a fertilised ovule? How is the triploid condition achieved?
Identity the part of embryo sac which takes part in formation of primary endosperm nucleus during fertlisation
Give a term for the following:
Fusion of male gamete and secondary nucleus in angiosperms.
