Plant Growth and Development
Test 5

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which plant growth regulator promotes the formation of female flowers in cucumbers, increasing their yield?

Auxin
Gibberellin
Cytokinin
Ethylene
4

Ethylene promotes the formation of female flowers in cucumbers, which helps increase yield.

Which plant growth phase is associated with increased vacuolation, cell enlargement, and new cell wall deposition?

Meristematic phase
Elongation phase
Maturation phase
Stationary phase
2

During the elongation phase, cells increase in size due to vacuolation, enlargement, and new cell wall deposition.

Which type of meristem is responsible for secondary growth in dicotyledonous plants?

Apical meristem
Intercalary meristem
Lateral meristem
Primary meristem
3

Lateral meristem, such as vascular cambium and cork cambium, is responsible for secondary growth in dicots.

Which plant hormone is known to regulate stomatal closure during water stress?

Auxin
Gibberellin
Abscisic acid
Cytokinin
3

Abscisic acid (ABA) acts as a stress hormone and triggers stomatal closure to reduce water loss during drought.

Which statement about senescence in plants is incorrect?

Senescence involves the degradation of chlorophyll.
Cytokinins accelerate senescence.
Ethylene promotes leaf abscission.
Senescence is a form of programmed cell death.
2

Cytokinins delay senescence; they do not accelerate it. Ethylene promotes senescence and abscission.

Select the incorrect statement about plant growth phases:

The lag phase shows slow growth.
The log phase shows rapid growth.
The stationary phase shows reduced growth.
The maturation phase occurs before the elongation phase.
4

The maturation phase occurs after the elongation phase, not before.

Which statement regarding lateral meristem is correct?

Lateral meristems contribute to primary growth.
Vascular cambium is a lateral meristem.
Lateral meristem is found only in monocots.
Lateral meristems increase plant height.
2

The vascular cambium is a type of lateral meristem responsible for secondary growth, increasing girth (thickness) in dicots.

Which plant hormone was first discovered due to its role in the 'foolish seedling' disease of rice?

Auxin
Gibberellin
Ethylene
Cytokinin
2

Gibberellins were discovered from the 'foolish seedling' disease of rice caused by the fungus *Gibberella fujikuroi*.

In arithmetic growth, how does the length of an organ change over time?

Exponentially
Linearly
Logarithmically
Randomly
2

In arithmetic growth, the length increases linearly with time, producing a straight-line graph.

What is the function of kinetin, a cytokinin discovered from autoclaved herring sperm DNA?

Promotes fruit ripening
Promotes cell division
Induces seed dormancy
Promotes apical dominance
2

Kinetin is a cytokinin that promotes cell division (cytokinesis) and is widely used in tissue culture.

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