Complete Plant Growth & Development Question Bank & Solutions (50 Questions)
Q1 of 50
NEET NCERT Line-by-Line
Growth in plants is best described as:
(A)
A reversible increase in size
(B)
An irreversible, permanent increase in size
(C)
A temporary swelling
(D)
Only an increase in fresh weight
Show Answer & NCERT Explanation
Correct Answer: (B) An irreversible, permanent increase in size
Growth is an irreversible, permanent increase in size with increase in dry weight & cell number.
Q2 of 50
NEET NCERT Line-by-Line
Length (primary) growth is due to:
(A)
Lateral meristem
(B)
Apical & intercalary meristems
(C)
Cork cambium
(D)
Vascular cambium
Show Answer & NCERT Explanation
Correct Answer: (B) Apical & intercalary meristems
Apical and intercalary meristems produce primary (length) growth.
Q3 of 50
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Secondary (girth) growth is caused by:
(A)
Apical meristem
(B)
Intercalary meristem
(C)
Lateral meristem
(D)
Ground tissue
Show Answer & NCERT Explanation
Correct Answer: (C) Lateral meristem
Lateral meristems (vascular & cork cambium) increase girth.
Q4 of 50
NEET NCERT Line-by-Line
The three phases of growth in order are:
(A)
Elongation, division, maturation
(B)
Division, elongation, maturation
(C)
Maturation, division, elongation
(D)
Division, maturation, elongation
Show Answer & NCERT Explanation
Correct Answer: (B) Division, elongation, maturation
Meristematic (division) → elongation → maturation.
Q5 of 50
NEET NCERT Line-by-Line
In arithmetic growth, after mitosis:
(A)
Both daughter cells divide
(B)
Only one daughter cell continues to divide
(C)
No cell divides
(D)
Cells fuse
Show Answer & NCERT Explanation
Correct Answer: (B) Only one daughter cell continues to divide
Only one daughter cell keeps dividing; the other differentiates (linear growth).
Q6 of 50
NEET NCERT Line-by-Line
The exponential growth equation is:
(A)
Lₜ = L₀ + rt
(B)
W₁ = W₀ e^(rt)
(C)
W = mg
(D)
r = L/t
Show Answer & NCERT Explanation
Correct Answer: (B) W₁ = W₀ e^(rt)
W₁ = W₀·e^(rt) describes geometric/exponential growth.
Q7 of 50
NEET NCERT Line-by-Line
A typical growth curve is:
(A)
Linear
(B)
Sigmoid (S-shaped)
(C)
Circular
(D)
Parabolic only
Show Answer & NCERT Explanation
Correct Answer: (B) Sigmoid (S-shaped)
Growth follows a sigmoid (S-shaped) curve.
Q8 of 50
NEET NCERT Line-by-Line
The phases of the sigmoid growth curve are:
(A)
Lag, log, stationary
(B)
Slow, fast, faster
(C)
Start, middle, end
(D)
Log, lag, decline
Show Answer & NCERT Explanation
Correct Answer: (A) Lag, log, stationary
Lag → log (exponential) → stationary phases.
Q9 of 50
NEET NCERT Line-by-Line
Relative growth rate is growth per unit time expressed:
(A)
Per unit area
(B)
Per unit initial size
(C)
Per gram of soil
(D)
Per leaf
Show Answer & NCERT Explanation
Correct Answer: (B) Per unit initial size
RGR is expressed per unit initial size for fair comparison.
Q10 of 50
NEET NCERT Line-by-Line
Cell elongation depends most directly on:
(A)
Oxygen
(B)
Water (turgor)
(C)
Nitrogen
(D)
Light
Show Answer & NCERT Explanation
Correct Answer: (B) Water (turgor)
Water provides the turgor that drives cell enlargement.
Q11 of 50
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Maturation of meristem cells into specialised cells is:
(A)
Dedifferentiation
(B)
Differentiation
(C)
Redifferentiation
(D)
Senescence
Show Answer & NCERT Explanation
Correct Answer: (B) Differentiation
Differentiation = cells maturing into specialised structures.
Q12 of 50
NEET NCERT Line-by-Line
Formation of cork cambium from mature cells is an example of:
(A)
Differentiation
(B)
Dedifferentiation
(C)
Redifferentiation
(D)
Abscission
Show Answer & NCERT Explanation
Correct Answer: (B) Dedifferentiation
Mature cells regaining the power to divide = dedifferentiation.
Q13 of 50
NEET NCERT Line-by-Line
Development equals:
(A)
Growth only
(B)
Differentiation only
(C)
Growth + differentiation
(D)
Senescence + growth
Show Answer & NCERT Explanation
Correct Answer: (C) Growth + differentiation
Development is the sum of growth and differentiation.
Q14 of 50
NEET NCERT Line-by-Line
Different leaf shapes on the same plant illustrate:
(A)
Vernalization
(B)
Heterophylly (plasticity)
(C)
Photoperiodism
(D)
Senescence
Show Answer & NCERT Explanation
Correct Answer: (B) Heterophylly (plasticity)
Heterophylly is an example of developmental plasticity.
Q15 of 50
NEET NCERT Line-by-Line
The natural auxin is:
(A)
GA₃
(B)
IAA
(C)
Zeatin
(D)
Ethephon
Show Answer & NCERT Explanation
Correct Answer: (B) IAA
Indole-3-acetic acid (IAA) is the natural auxin.
Q16 of 50
NEET NCERT Line-by-Line
Auxin was isolated by:
(A)
Garner & Allard
(B)
F.W. Went
(C)
Skoog & Miller
(D)
Kurosawa
Show Answer & NCERT Explanation
Correct Answer: (B) F.W. Went
F.W. Went isolated auxin from oat coleoptile tips.
Q17 of 50
NEET NCERT Line-by-Line
Apical dominance is controlled by:
(A)
Cytokinin
(B)
Auxin
(C)
Ethylene
(D)
ABA
Show Answer & NCERT Explanation
Correct Answer: (B) Auxin
Auxin from the apical bud suppresses lateral bud growth.
Q18 of 50
NEET NCERT Line-by-Line
The herbicide 2,4-D is a synthetic:
(A)
Cytokinin
(B)
Gibberellin
(C)
Auxin
(D)
Ethylene
Show Answer & NCERT Explanation
Correct Answer: (C) Auxin
2,4-D is an auxin used to kill dicot weeds.
Q19 of 50
NEET NCERT Line-by-Line
Gibberellins were first obtained from:
(A)
Herring sperm DNA
(B)
Gibberella fujikuroi
(C)
Coconut milk
(D)
Oat tips
Show Answer & NCERT Explanation
Correct Answer: (B) Gibberella fujikuroi
Gibberellins came from the fungus Gibberella fujikuroi.
Q20 of 50
NEET NCERT Line-by-Line
Bolting refers to:
(A)
Fruit ripening
(B)
Sudden internode elongation
(C)
Leaf fall
(D)
Stomatal closure
Show Answer & NCERT Explanation
Correct Answer: (B) Sudden internode elongation
Bolting is internode elongation in rosette plants, caused by gibberellins.
Q21 of 50
NEET NCERT Line-by-Line
Gibberellins speed up which industrial process?
(A)
Tanning
(B)
Malting (brewing)
(C)
Photography
(D)
Dyeing
Show Answer & NCERT Explanation
Correct Answer: (B) Malting (brewing)
Gibberellins accelerate malting in the brewing industry.
Q22 of 50
NEET NCERT Line-by-Line
A natural cytokinin is:
(A)
Kinetin
(B)
Zeatin
(C)
2,4-D
(D)
IBA
Show Answer & NCERT Explanation
Correct Answer: (B) Zeatin
Zeatin (from maize/coconut milk) is a natural cytokinin.
Q23 of 50
NEET NCERT Line-by-Line
Kinetin was first obtained from:
(A)
Maize kernels
(B)
Herring sperm DNA
(C)
Coconut milk
(D)
Rice fungus
Show Answer & NCERT Explanation
Correct Answer: (B) Herring sperm DNA
Kinetin came from herring sperm DNA; it is not natural in plants.
Q24 of 50
NEET NCERT Line-by-Line
The main role of cytokinins is to promote:
(A)
Stomatal closure
(B)
Cell division (cytokinesis)
(C)
Fruit ripening
(D)
Dormancy
Show Answer & NCERT Explanation
Correct Answer: (B) Cell division (cytokinesis)
Cytokinins promote cell division and delay senescence.
Q25 of 50
NEET NCERT Line-by-Line
Delay of leaf senescence by cytokinins is the:
(A)
Triple response
(B)
Richmond–Lang effect
(C)
Avena curvature
(D)
Bakanae effect
Show Answer & NCERT Explanation
Correct Answer: (B) Richmond–Lang effect
The Richmond–Lang effect is cytokinin-induced delay of senescence.
Q26 of 50
NEET NCERT Line-by-Line
The only gaseous plant growth regulator is:
(A)
IAA
(B)
Ethylene
(C)
GA₃
(D)
ABA
Show Answer & NCERT Explanation
Correct Answer: (B) Ethylene
Ethylene is the gaseous PGR.
Q27 of 50
NEET NCERT Line-by-Line
Fruit ripening is promoted by:
(A)
Auxin
(B)
Ethylene
(C)
Cytokinin
(D)
ABA
Show Answer & NCERT Explanation
Correct Answer: (B) Ethylene
Ethylene promotes ripening of climacteric fruits.
Q28 of 50
NEET NCERT Line-by-Line
Ethylene induces ____ flowers in cucurbits.
(A)
Male
(B)
Female
(C)
Sterile
(D)
No
Show Answer & NCERT Explanation
Correct Answer: (B) Female
Ethylene promotes female flower formation in cucurbits.
Q29 of 50
NEET NCERT Line-by-Line
The "stress hormone" of plants is:
(A)
Auxin
(B)
Gibberellin
(C)
Abscisic acid
(D)
Cytokinin
Show Answer & NCERT Explanation
Correct Answer: (C) Abscisic acid
ABA is the stress hormone; it acts under unfavourable conditions.
Q30 of 50
NEET NCERT Line-by-Line
ABA causes stomata to:
(A)
Open
(B)
Close
(C)
Enlarge
(D)
Disappear
Show Answer & NCERT Explanation
Correct Answer: (B) Close
ABA closes stomata under water stress, reducing transpiration.
Q31 of 50
NEET NCERT Line-by-Line
ABA acts as an antagonist of:
(A)
Auxin
(B)
Cytokinin
(C)
Gibberellin
(D)
Ethylene
Show Answer & NCERT Explanation
Correct Answer: (C) Gibberellin
ABA antagonises gibberellins (e.g. in dormancy vs germination).
Q32 of 50
NEET NCERT Line-by-Line
Photoperiodism was discovered by:
(A)
Darwin
(B)
Garner & Allard
(C)
Went
(D)
Skoog
Show Answer & NCERT Explanation
Correct Answer: (B) Garner & Allard
Garner & Allard discovered photoperiodism.
Q33 of 50
NEET NCERT Line-by-Line
In flowering, the critical factor is the length of the:
(A)
Light period
(B)
Dark (night) period
(C)
Twilight
(D)
Day plus night
Show Answer & NCERT Explanation
Correct Answer: (B) Dark (night) period
The duration of the dark period is critical for flowering.
Q34 of 50
NEET NCERT Line-by-Line
Short-day plants flower when the night is:
(A)
Shorter than critical
(B)
Longer than critical
(C)
Exactly 12 h
(D)
Absent
Show Answer & NCERT Explanation
Correct Answer: (B) Longer than critical
SDPs flower when the dark period exceeds a critical length.
Q35 of 50
NEET NCERT Line-by-Line
Which is a long-day plant?
(A)
Rice
(B)
Chrysanthemum
(C)
Spinach
(D)
Tobacco
Show Answer & NCERT Explanation
Correct Answer: (C) Spinach
Spinach is a long-day plant; the others are short-day plants.
Q36 of 50
NEET NCERT Line-by-Line
Which is a day-neutral plant?
(A)
Soybean
(B)
Tomato
(C)
Xanthium
(D)
Henbane
Show Answer & NCERT Explanation
Correct Answer: (B) Tomato
Tomato flowers independently of photoperiod (day-neutral).
Q37 of 50
NEET NCERT Line-by-Line
The photoperiod is perceived by the:
(A)
Roots
(B)
Leaves
(C)
Stem apex
(D)
Flowers
Show Answer & NCERT Explanation
Correct Answer: (B) Leaves
Leaves perceive the photoperiod via phytochrome.
Q38 of 50
NEET NCERT Line-by-Line
The hypothetical flowering hormone is:
(A)
Florigen
(B)
Auxin
(C)
Zeatin
(D)
Phytochrome
Show Answer & NCERT Explanation
Correct Answer: (A) Florigen
Florigen is the hypothetical hormone that induces flowering.
Q39 of 50
NEET NCERT Line-by-Line
The pigment involved in photoperiodic timing is:
(A)
Chlorophyll
(B)
Phytochrome
(C)
Carotenoid
(D)
Anthocyanin
Show Answer & NCERT Explanation
Correct Answer: (B) Phytochrome
Phytochrome perceives light/dark periods.
Q40 of 50
NEET NCERT Line-by-Line
Vernalization is the promotion of flowering by:
(A)
High temperature
(B)
Low temperature (cold)
(C)
Long days
(D)
Drought
Show Answer & NCERT Explanation
Correct Answer: (B) Low temperature (cold)
Vernalization is cold-induced promotion of flowering.
Q41 of 50
NEET NCERT Line-by-Line
Which needs vernalization?
(A)
Tomato
(B)
Winter wheat
(C)
Sunflower
(D)
Maize
Show Answer & NCERT Explanation
Correct Answer: (B) Winter wheat
Winter wheat requires a cold period to flower.
Q42 of 50
NEET NCERT Line-by-Line
Reversal of vernalization by heat is called:
(A)
Devernalization
(B)
Dedifferentiation
(C)
Senescence
(D)
Bolting
Show Answer & NCERT Explanation
Correct Answer: (A) Devernalization
High temperature can reverse vernalization (devernalization).
Q43 of 50
NEET NCERT Line-by-Line
The Avena curvature test is a bioassay for:
(A)
Gibberellin
(B)
Auxin
(C)
Cytokinin
(D)
ABA
Show Answer & NCERT Explanation
Correct Answer: (B) Auxin
The Avena (oat coleoptile) curvature test measures auxin activity.
Q44 of 50
NEET NCERT Line-by-Line
Parthenocarpy means production of:
(A)
Many seeds
(B)
Seedless fruit without fertilisation
(C)
Large leaves
(D)
Adventitious roots
Show Answer & NCERT Explanation
Correct Answer: (B) Seedless fruit without fertilisation
Parthenocarpy = seedless fruit formed without fertilisation.
Q45 of 50
NEET NCERT Line-by-Line
Promoter group of PGRs includes:
(A)
Auxin, gibberellin, cytokinin
(B)
Only ABA
(C)
Ethylene & ABA
(D)
Only ethylene
Show Answer & NCERT Explanation
Correct Answer: (A) Auxin, gibberellin, cytokinin
Auxins, gibberellins and cytokinins are growth promoters.
Q46 of 50
NEET NCERT Line-by-Line
Adventitious root formation in cuttings is promoted by:
(A)
ABA
(B)
Auxins
(C)
Ethylene gas only
(D)
Phytochrome
Show Answer & NCERT Explanation
Correct Answer: (B) Auxins
Auxins (e.g. IBA, NAA) promote rooting in stem cuttings.
Q47 of 50
NEET NCERT Line-by-Line
The "bakanae" (foolish-seedling) disease of rice is linked to:
(A)
Auxin
(B)
Gibberellin
(C)
Cytokinin
(D)
ABA
Show Answer & NCERT Explanation
Correct Answer: (B) Gibberellin
Excess gibberellin from Gibberella causes abnormal elongation in rice.
Q48 of 50
NEET NCERT Line-by-Line
In cereal seeds, gibberellins trigger synthesis of:
(A)
Cellulase
(B)
α-amylase
(C)
Pepsin
(D)
Rennin
Show Answer & NCERT Explanation
Correct Answer: (B) α-amylase
Gibberellins induce α-amylase in the aleurone to mobilise starch.
Q49 of 50
NEET NCERT Line-by-Line
The triple response of seedlings is caused by:
(A)
Auxin
(B)
Gibberellin
(C)
Ethylene
(D)
ABA
Show Answer & NCERT Explanation
Correct Answer: (C) Ethylene
Ethylene causes shorter, thicker, horizontally growing stems (triple response).
Q50 of 50
NEET NCERT Line-by-Line
Which pair is correctly antagonistic?
(A)
Auxin & cytokinin
(B)
Gibberellin & ABA
(C)
Ethylene & auxin
(D)
Cytokinin & zeatin
Show Answer & NCERT Explanation
Correct Answer: (B) Gibberellin & ABA
Gibberellins and ABA act antagonistically in dormancy/germination.