Plant Growth and Development Chapter-Wise Test 8

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which scientist discovered that gibberellins cause abnormal elongation of rice seedlings?

Charles Darwin
E. Kurosawa
F.W. Went
H.H. Cousins
2

E. Kurosawa discovered that gibberellins from the fungus *Gibberella fujikuroi* caused abnormal elongation in rice seedlings.

Which plant growth regulator delays leaf senescence and promotes nutrient mobilization?

Auxin
Cytokinin
Gibberellin
Abscisic acid
2

Cytokinins delay leaf senescence by mobilizing nutrients and promoting cell division.

Select the incorrect statement regarding auxins:

Auxins promote root initiation.
Auxins inhibit lateral bud growth.
2,4-D is a natural auxin.
IAA is a naturally occurring auxin.
3

2,4-D (2,4-dichlorophenoxyacetic acid) is a synthetic auxin, not a natural one. IAA (indole-3-acetic acid) is a natural auxin.

Which statement about plant hormones is correct?

Ethylene inhibits fruit ripening.
Auxin promotes lateral bud growth.
Abscisic acid induces seed dormancy.
Gibberellins prevent seed germination.
3

Abscisic acid induces seed dormancy and inhibits germination. Ethylene promotes fruit ripening, and auxin suppresses lateral bud growth (apical dominance).

Which of the following statements about senescence is correct?

Senescence involves the synthesis of chlorophyll.
Ethylene delays senescence.
Cytokinins promote leaf senescence.
Senescence is a form of programmed cell death.
4

Senescence is a programmed cell death process involving the breakdown of cellular components. Ethylene accelerates senescence, while cytokinins delay it.

Which of the following statements about auxin is incorrect?

Auxin promotes cell elongation.
Auxin promotes root initiation.
Auxin inhibits apical dominance.
Indole-3-acetic acid (IAA) is a natural auxin.
3

Auxin promotes apical dominance; it does not inhibit it. Cytokinins help overcome apical dominance.

Select the correct statement regarding parthenocarpy:

Parthenocarpy results in seedless fruits.
Parthenocarpy is induced only by cytokinins.
Parthenocarpy requires fertilization.
Parthenocarpy is common in cereals.
1

Parthenocarpy is the development of seedless fruits without fertilization. Auxins and gibberellins can induce parthenocarpy, not only cytokinins.

Which plant growth regulator is used to promote parthenocarpy in fruits like tomatoes?

Cytokinin
Gibberellin
Auxin
Ethylene
3

Auxin is commonly used to induce parthenocarpy, which results in seedless fruit development.

Which of the following statements about seed germination is correct?

Water absorption is not essential for germination.
Gibberellins promote the production of hydrolytic enzymes.
Abscisic acid accelerates seed germination.
Seed germination is independent of temperature.
2

Gibberellins stimulate the production of enzymes like alpha-amylase, which breaks down starch during seed germination. Water, temperature, and oxygen are essential for germination.

What type of curve is obtained when growth is plotted against time in geometric growth?

Linear curve
S-shaped curve
Parabolic curve
Exponential curve
4

In geometric growth, plotting growth against time results in an exponential curve during the log phase.

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