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501 questions in this collection · Page 14 of 51
Question 131 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
The hollow foliar structure enclosing the shoot apex in monocots is:
Epicotyl has a shoot apex and a few leaf primordia enclosed in a hollow foliar structure, the coleoptile.
Question 132 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Seed dormancy is triggered by:
As the seed matures, its water content is reduced... The general metabolic activity of the embryo slows down. The embryo may enter a state of inactivity called dormancy.
Question 133 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
A seed is essentially a:
In angiosperms, the seed is the final product of sexual reproduction. It is often described as a fertilised ovule.
Question 134 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
The oldest viable seed, Lupinus arcticus, was excavated from:
The oldest is that of a lupine, Lupinus arcticus excavated from Arctic Tundra.
Question 135 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Parasitic species like Orobanche produce:
Similar is the case in fruits of some parasitic species such as Orobanche and Striga. (Referring to thousands of tiny seeds).
Question 136 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Apomixis is observed in species of:
A few flowering plants such as some species of Asteraceae and grasses, have evolved a special mechanism... called apomixis.
Question 137 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
In Citrus and Mango, polyembryony arises from:
In many Citrus and Mango varieties some of the nucellar cells surrounding the embryo sac start dividing, protrude into the embryo sac and develop into the embryos.
Question 138 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Hybrid seeds have to be produced every year because:
If the seeds collected from hybrids are sown, the plants in the progeny will segregate and do not maintain hybrid characters.
Question 139 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
A typical microsporangium appears ________ in transverse section.
In a transverse section, a typical microsporangium appears near circular in outline.
Question 140 of 501
📘 CLASS XII
Sexual Reproduction In Flowering Plants
Which layer of the microsporangium helps in dehiscence of anther?
The outer three wall layers perform the function of protection and help in dehiscence of anther.