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प्रश्न
Describe the development of an endosperm in a viable seed. Why does endosperm development precedes embryo development?
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उत्तर
The endosperm development is a result of triple fusion. During triple fusion, one of the male gametes fuses with the two polar nuclei of the central cell and give rise to primary endosperm cell (PEC). The primary endosperm cell divides repeatedly and forms a triploid endosperm tissue. The most common type of endosperm development is free-nuclear, in which the PEN undergoes successive nuclear divisions to give rise to a number of free nuclei. The endosperm thus formed is called free nuclear endosperm. Subsequently, cell formation occurs and the endosperm becomes cellular.
The endosperm thus developed is required to provide essential nutrients to the growing embryo. Therefore endosperm development occurs before the embryo development.
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संबंधित प्रश्न
Draw a labelled mature stage of a dicotyledonous embryo.
Endosperm of angiosperm is __________.
(A) haploid
(B) diploid
(C) triploid
(D) tetraploid
Describe the formation of helobial endosperm
Why does endosperm development precede embryo development in angiosperm seeds?
Identify the CORRECT statement/s from the following.
i. In post-fertilization changes within the ovule, the development of embryo is followed by the development of endosperm.
ii. Helobial endosperm is intermediate between cellular and nuclear type endosperm.
iii. Helobial endosperm is mostly observed in 72 families of dicots.
In angiosperms, triple fusion is required for the formation of ______.
If the endosperm cell of an angiosperm contains 24 chromosomes, the number of chromosomes in the root tip cells will be ______.
Coconut water contains:
Why does the zygote begin to divide only after the division of Primary endosperm cell (PEC)?
The diagram given below shows the three types of endosperms in angiosperms.
 |
 |
 |
| Type 1 | Type 2 | Type 3 |
- Identify the three types of endosperms shown above.
- Name the type of endosperm which commonly occurs in polypetalous dicots.
