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प्रश्न
Describe the development of an endosperm in a viable seed. Why does endosperm development precedes embryo development?
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
Some organisms suspend their metabolic activities to survive in unfavourable conditions. Explain with the help of any four examples.
Draw a labelled mature stage of a dicotyledonous embryo.
Endosperm of angiosperm is __________.
(A) haploid
(B) diploid
(C) triploid
(D) tetraploid
______ is the first cell of female gametophytic generation in angiosperms.
At what stage of endosperm development, will you observe nuclear or cellular type of endosperm?
In dicots, the pollen grains are usually ______
The endosperm of gymnosperms is ______.
Coconut water contains:
The type of evolution where the central part is occupied by free nuclear and the peripheral part by cells is observed in ______.
The diagram given below shows the three types of endosperms in angiosperms.
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 |
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| 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.
