Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Seeds of a large number of species live for several years.
Reason (R): As the seed matures, its water content is reduced and the general metabolic activity of the embryo speeds up.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A) is true but (R) is false.
As a seed matures it loses water and its embryo becomes less active. This dry, slowed-down state lets many seeds stay alive (viable) for a long time after they are shed.
Assertion (A): Seeds of a large number of species live for several years. — True. Seed viability varies a lot. Seeds of a few species lose viability within a few months, but the seeds of a large number of species live for several years, and some even for hundreds of years.
Reason (R): As the seed matures, its water content is reduced and the general metabolic activity of the embryo speeds up. — False. The first part is right: the seed dries to about 10-15 per cent moisture. But the metabolic activity of the embryo slows down; it does not speed up. The embryo may then enter dormancy.
So A is true but R is false.
NCERT Extract:
Seed – “… As the seed matures, its water content is reduced and seeds become relatively dry (10-15 per cent moisture by mass). The general metabolic activity of the embryo slows down. The embryo may enter a state of inactivity called dormancy, or if favourable conditions are available (adequate moisture, oxygen and suitable temperature), they germinate.”
Seed – “… In a few species the seeds lose viability within a few months. Seeds of a large number of species live for several years. Some seeds can remain alive for hundreds of years.”