Plant Growth and Development Chapter-Wise Test 9

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which phase of growth is represented by a plateau in the sigmoid growth curve?

Lag phase
Log phase
Stationary phase
Exponential phase
3

The stationary phase is represented by a plateau in the sigmoid growth curve, where the growth rate stabilizes.

Which plant hormone increases sugar yield in sugarcane by promoting stem elongation?

Auxin
Gibberellin
Cytokinin
Abscisic acid
2

Gibberellins increase internode length in sugarcane, thereby increasing sugar yield per plant.

Which plant hormone accelerates the abscission of leaves and fruits?

Auxin
Gibberellin
Abscisic acid
Ethylene
4

Ethylene promotes senescence and abscission of plant organs, including leaves and fruits.

Which type of cell division produces new cells in the root apical meristem?

Meiosis
Mitosis
Binary fission
Budding
2

Mitosis occurs in the root apical meristem, producing genetically identical daughter cells for growth.

Which type of growth occurs due to the activity of intercalary meristem?

Primary growth
Secondary growth
Apical growth
Lateral growth
1

Intercalary meristems contribute to primary growth by elongating internodes, especially in grasses.

Which plant growth regulator is referred to as the 'stress hormone'?

Cytokinin
Abscisic acid
Auxin
Gibberellin
2

Abscisic acid (ABA) is called the stress hormone as it helps plants respond to drought by closing stomata and inducing dormancy.

Select the incorrect statement regarding senescence and abscission:

Senescence involves the breakdown of cellular components.
Ethylene accelerates leaf abscission.
Cytokinins promote leaf abscission.
Senescence is a form of programmed cell death.
3

Cytokinins delay, not promote, leaf abscission. Ethylene promotes abscission and senescence.

Which type of heterophylly occurs in cotton where juvenile and mature leaves differ in shape?

Habitual heterophylly
Environmental heterophylly
Developmental heterophylly
Physiological heterophylly
3

Developmental heterophylly occurs in cotton, where leaves show different shapes during juvenile and mature stages.

Which phase of growth shows the highest increase in protoplasm content?

Maturation phase
Elongation phase
Meristematic phase
Senescent phase
3

In the meristematic phase, cells actively divide and have high protoplasm content with large nuclei.

Which plant growth regulator was discovered through experiments on tobacco stem callus proliferation?

Auxin
Gibberellin
Cytokinin
Abscisic acid
3

Cytokinin was discovered by F. Skoog and co-workers during experiments on tobacco stem callus proliferation.

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