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प्रश्न
Give an account of polyembryony.
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उत्तर
Polyembryony:
- Polyembryony is the occurrence of more than one embryo in a seed which consequently results in the emergence of multiple seedlings.
- The additional embryos result from the differentiation and development of various maternal and zygotic tissues associated with the ovule of the seed.
- In adventive polyembryony, an embryo develops directly from the diploid cell of nucellus and integuments as in Citrus.
- In cleavage polyembryony, zygote proembryo sometimes divides (cleaves) into many parts or units. Each unit then develops into an embryo.
APPEARS IN
संबंधित प्रश्न
Mention one advantage of apomictic seeds to farmers.
Answer the following question.
When a seed of orange is squeezed, many embryos, instead of one are observed. Explain how it is possible.
Fill in the blank:
The ________contains the egg or ovum.
Fill in the blank:
________takes place when one male gamete and the egg fuse together. The fertilized egg grows into a seed from which the new plants can grow.
Once the pollen reaches the stigma, the pollen tube traverses down the ________ to the ovary where fertilization occurs.
Fill in the blank:
The whorl ________is green that protects the flower until it opens.
Match the column.
| Column - I (Structure before seed formation) |
Column - II (Structure after seed formation) |
||
| A. | Funiculus | I. | Hilum |
| B. | Scar of ovule | II. | Tegmen |
| C. | Zygote | III. | Testa |
| D. | Inner integument | IV. | Stalk of seed |
| V. | Embryo | ||
The polyembryony commonly occurs in ______.
The occurrence of two or more embryos in one ovule is called ______
Adventive polyembryony in citrus is due to ______.
