The female gametophyte of a typical dicot is also known as:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Embryo sac
Explanation: Located in the nucellus is the embryo sac or female gametophyte.
In the 8-nucleate stage of the embryo sac, the division is strictly:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Free nuclear
Explanation: These mitotic divisions are strictly free nuclear, that is, nuclear divisions are not followed immediately by cell wall formation.
The three cells grouped together at the micropylar end of the embryo sac constitute the:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Egg apparatus
Explanation: Three cells are grouped together at the micropylar end and constitute the egg apparatus.
The large central cell of the embryo sac contains:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Two polar nuclei
Explanation: The large central cell, as mentioned earlier, has two polar nuclei.
Plants like Commelina produce:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: C
Answer: Both chasmogamous and cleistogamous flowers
Explanation: Plants such as Viola, Oxalis, and Commelina produce two types of flowers – chasmogamous and cleistogamous.
Genetic self-incompatibility involves:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Inhibition of pollen germination or tube growth
Explanation: Self-incompatibility is a genetic mechanism that prevents self-pollen from fertilizing ovules by inhibiting pollen germination or pollen tube growth in the pistil.
Which agent is most common for abiotic pollination?
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Wind
Explanation: Pollination by wind is more common amongst abiotic pollinations.
Wind-pollinated flowers often have:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: A single ovule in each ovary
Explanation: Wind-pollinated flowers often have a single ovule in each ovary and numerous flowers packed into an inflorescence.
In Vallisneria, female flowers reach the water surface by:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: A
Answer: Long stalks
Explanation: In Vallisneria, the female flower reach the surface of water by the long stalk.
Pollen grains of water-pollinated species are protected from wetting by:
[Sexual-Reproduction-in-Flowering-Plants] [class-xii]
Correct Option: B
Answer: Mucilaginous covering
Explanation: In most of the water-pollinated species, pollen grains are protected from wetting by a mucilaginous covering.