1. Which plant hormone generally helps break seed dormancy?
A.
Abscisic acid
B.
Gibberellin
C.
Ethylene
D.
Cytokinin
Correct Answer:
Gibberellin
Explanation:
Gibberellins promote germination and help break seed dormancy, whereas abscisic acid generally maintains dormancy.
2. Abscisic acid mainly maintains seed dormancy by:
A.
Promoting immediate germination
B.
Inhibiting seed germination
C.
Increasing oxygen absorption
D.
Softening the seed coat
Correct Answer:
Inhibiting seed germination
Explanation:
Abscisic acid maintains dormancy by inhibiting germination. A reduction in its effect can help dormancy breaking.
3. Which condition is commonly required for breaking dormancy in a dry seed?
A.
Water absorption
B.
Complete darkness in every case
C.
Permanent dryness
D.
Removal of oxygen
Correct Answer:
Water absorption
Explanation:
Water absorption, or imbibition, activates the seed and is an important first step in breaking dormancy.
4. The process of rubbing or weakening a hard seed coat to break dormancy is called:
A.
Stratification
B.
Scarification
C.
Pollination
D.
Transpiration
Correct Answer:
Scarification
Explanation:
Scarification weakens or breaks the hard seed coat, allowing water and oxygen to enter and helping the seed overcome dormancy.
5. Cold treatment used to break dormancy in some seeds is known as:
A.
Scarification
B.
Stratification
C.
Fermentation
D.
Grafting
Correct Answer:
Stratification
Explanation:
Stratification exposes seeds to suitable low-temperature conditions that can help break dormancy and permit germination.
6. Which treatment can help break dormancy caused by a hard seed coat?
A.
Scarifying the seed coat
B.
Keeping the seed completely dry
C.
Removing all oxygen
D.
Increasing abscisic acid levels
Correct Answer:
Scarifying the seed coat
Explanation:
Scarification makes the hard seed coat more permeable to water and gases, helping the dormant seed begin germination.
7. Dormancy is more likely to be broken when the effect of which hormone decreases?
A.
Abscisic acid
B.
Gibberellin
C.
Auxin
D.
Cytokinin
Correct Answer:
Abscisic acid
Explanation:
Abscisic acid promotes and maintains seed dormancy, so reducing its effect favors dormancy breaking and germination.
8. Which hormone counteracts abscisic acid during the breaking of seed dormancy?
A.
Gibberellin
B.
Ethylene
C.
Auxin
D.
Cytokinin
Correct Answer:
Gibberellin
Explanation:
Gibberellin promotes germination and counteracts the dormancy-maintaining action of abscisic acid.
9. Why does removing or weakening the seed coat help break dormancy?
A.
It prevents water entry
B.
It allows water and oxygen to reach the embryo
C.
It increases abscisic acid production
D.
It stops all enzyme activity
Correct Answer:
It allows water and oxygen to reach the embryo
Explanation:
A weakened seed coat permits water and oxygen to enter, supporting the processes needed to overcome dormancy and start germination.
10. A seed treated with a suitable gibberellin solution is most likely to:
A.
Remain dormant for a longer time
B.
Break dormancy and germinate
C.
Lose all stored food
D.
Stop absorbing water
Correct Answer:
Break dormancy and germinate
Explanation:
Gibberellin treatment can promote the breaking of dormancy and stimulate germination in suitable seeds.
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