Plant Growth and Development — Page 4 | NEET Biology

Q31

Treatment of seed at low temperature under moist conditions to break its dormancy is called

A vernalization

B chelation

C stratification

D scarification

Correct Answer

Option C

Solution

(c) Stratification = cold-moist treatment of seeds to break dormancy.

Q32

Importance of day length in flowering of plants was first shown in

A lemna

B tobacco

C cotton

D petunia

Correct Answer

Option B

Solution

(b) Garner and Allard (1920) first demonstrated photoperiodism in tobacco.

Q33

Photoperiodism was first characterised in

A tobacco

B potato

C tomato

D cotton

Correct Answer

Option A

Solution

(a) Photoperiodism was first studied by Garner and Allard (1920) using tobacco (Maryland Mammoth).

Q34

Vernalization stimulates flowering in

A zamikand

B turmeric

C carrot

D ginger

Correct Answer

Option C

Solution

(c) Carrot is a biennial plant that requires vernalization to flower in its second season.

Q35

Through their effect on plant growth regulators, what do temperature and light control in plants?

A Apical dominance

B Flowering

C Closure of stomata

D Fruit elongation

Correct Answer

Option B

Solution

(b) Temperature and light control flowering through their effect on phytohormones.

Q36

Differentiation of shoot is controlled by

A high gibberellin:cytokinin ratio

B high auxin:cytokinin ratio

C high cytokinin:auxin ratio

D high gibberellin:auxin ratio

Correct Answer

Option C

Solution

(c) High cytokinin:auxin ratio promotes shoot differentiation in tissue culture.

Q37

Cell elongation in internodal regions of green plants takes place due to

A indole acetic acid

B cytokinins

C gibberellins

D ethylene

Correct Answer

Option C

Solution

(c) Gibberellins specifically stimulate internode elongation.

Q38

How does pruning help in making the hedge dense?

A It frees axillary buds from apical dominance

B The apical shoot grows faster after pruning

C It releases wound hormones

D It induces differentiation of new shoots from rootstock

Correct Answer

Option A

Solution

(a) Pruning removes apical bud; auxin-mediated apical dominance is removed, allowing lateral buds to grow.

Q39

An enzyme that can stimulate germination of barley seeds is

A lipase

B protease

C invertase

D alpha-amylase

Correct Answer

Option D

Solution

(d) Alpha-amylase digests starch endosperm to sugars for germination.

Q40

"Foolish seedling" disease of rice led to the discovery of

A ABA

B 2,4-D

C IAA

D GA

Correct Answer

Option D

Solution

(d) Gibberellins were discovered through the study of Bakanae (foolish seedling) disease of rice.