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प्रश्न
Explain the different types of endosperms in angiosperms.
Explain the development of the different types of endosperms in angiosperms.
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उत्तर
- Free-nuclear endosperm: This is the most common type. The primary endosperm nucleus divides repeatedly without cell wall formation, and the resulting nuclei remain free in the cytoplasm. Later, walls may form around the nuclei.
Example: Coconut water. - Cellular endosperm: Each nuclear division is immediately followed by cell wall formation, so the endosperm becomes cellular from the very beginning.
Examples: Peperomia, Villarsia, Drimys. - Helobial endosperm: This type is intermediate between the free-nuclear and cellular types. The first division of the primary endosperm nucleus is followed by a cell wall formation that separates the endosperm into a large micropylar chamber and a small chalazal chamber.
Examples: Vallisneria, Erimus.
संबंधित प्रश्न
List the three stages the annuals and biennial angiosperms have to pass through during their life cycle.
Read the statement and answer the questions that follow.
A flower of brinjal has 520 ovules in its ovary. However, it produces a fruit with only 480 viable seeds.
(a) What could have prevented the rest of the 40 ovules from maturing into viable seeds? Explain giving a reason.
(b) Describe the development of a dicot embryo in a viable seed.
(c) Why certain angiospermic seed albuminous while others are exalbuminous? Explain.
Give an example of an angiosperm seed that has a perisperm. Name the part the perisperm develops from.
Give a reason for the Following:
Pollen grains of wind-pollinated flowers are produced in large quantities.
A typical flower has ______ different kinds of whorl.
Science of cultivation, breeding, marketing and arrangement of flowers is called ______.
Pollen grains are well preserved as fossils because of the presence of ______
In a fertilized ovule, n, 2n, and 3n conditions occur respectively in ______
Place the following groups of plants in order, beginning with those that first appeared on the earth and progressing toward those that appeared most recently in time.
What is the similarity between gymnosperms and angiosperms?
