51 NEET Biology previous year questions on Plant Growth and Development — options free on every question; 5 include the answer & explanation free, the rest unlock with PYQ Pass.
Q1 FREE PREVIEW
PYQ
In the equation GPP - R = NPP. R represents:
aRetardation factor
bEnvironment factor
cRespiration losses
dRadiant energy
✓ Correct answer: c) Respiration losses
ExplanationGPP = Gross Primary Productivity (total energy fixed by photosynthesis) NPP = Net Primary Productivity (energy left for growth and consumption by other organisms) R = Respiration losses (energy used by producers for their own metabolic activities) Correct answer: C. Respiration losses
Q2 FREE PREVIEW
PYQ
The regulator which retards ageing/senescence of plant parts is
acytokinin
bauxin
cgibberellin
dabscisic acid
✓ Correct answer: a) cytokinin
ExplanationAnswer: A (cytokinin) Cytokinins are a class of plant hormones that promote cell division and differentiation.One of their most significant physiological effects is the ability to delay the process of aging, or senescence, in plant organs such as leaves, flowers, and fruits.This effect is sometimes referred to as the Richmond-Lang effect.Cytokinins achieve this by mobilizing nutrients to the treated area and maintaining metabolic activity.
Q3 FREE PREVIEW
PYQ
What is necessary for ripening for fruits?
a80% of ethylene
bAbscisic acid
c2,4 D
dA.M.O.-16
✓ Correct answer: a) 80% of ethylene
ExplanationEthylene is a natural, gaseous plant hormone that serves as the primary regulator and initiator of the fruit ripening process in many fruits (climacteric fruits like bananas, tomatoes, apples, etc.). Ethylene is responsible for a cascade of changes during ripening, including the breakdown of cell walls (softening), degradation of chlorophyll (color change from green), and conversion of starches into sugars (flavor and sweetness development).The concentration required for commercial artificial ripening is typically up to 100 ppm (parts per million), which is considered a safe alternative to harmful methods like calcium carbide.The option "80% of ethylene" refers to the high concentration or significant role of ethylene required relative to other factors/hormones.
Q4 FREE PREVIEW
PYQ
It takes very long time for pineapple plants to produce flowers. Which combination of hormones can be applied to artificially induce flowering in pineapple plants throughout the year to increase yield? [NEET 2019]
aAuxin and Ethylene
bGibberellin and Cytokinin
cGibberellin and Abscisic acid
dCytokinin and Abscisic acid
✓ Correct answer: a) Auxin and Ethylene
ExplanationCorrect Answer: A Explanation: In pineapple, flowering can be artificially induced by the application of ethylene.Ethylene is known to promote flowering in some plants, including pineapple, and is commercially used to ensure uniform and year-round flowering, thereby increasing yield.Auxins, when applied along with ethylene (or ethylene-releasing compounds like ethephon), enhance the effectiveness of this treatment by supporting growth responses associated with flowering induction.Gibberellins generally delay flowering in many plants.Abscisic acid is a growth inhibitor and does not promote flowering.Cytokinins are mainly involved in cell division and delay of senescence.
Q5 FREE PREVIEW
PYQ
Who coined the term Kinetin? [Re-NEET 2020]
aDarwin
bWent
cKurosawa
dSkoog and Miller
✓ Correct answer: d) Skoog and Miller
ExplanationThe term Kinetin was coined by Skoog and Miller in 1955. They discovered it while studying the effect of DNA breakdown products on plant cell division.Kinetin is a type of cytokinin, a plant hormone that promotes cell division (cytokinesis), especially in plant tissues like callus cultures.
Q6
PYQ
The ability of plants to follow different pathways in response to environment leading to formation of different kinds of structures is called
adifferentiation.
bredifferentiation.
cdevelopment.
dplasticity.
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Q7
PYQ
In tissue culture experiments, leaf mesophyll cells are put in a culture medium to form callus. This phenomenon may be called as: [NEET 2023]
aDedifferentiation
bDevelopment
cSenescence
dDifferentiation
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Q8
PYQ
Formation of interfascicular cambium from fully developed parenchyma cells is an example of [NEET 2024]
aMaturation
bDifferentiation
cRedifferentiation
dDedifferentiation
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Q9
PYQ
Spraying sugarcane crop with which of the following plant growth regulators, increases the length of stem, thus, increasing the yield? [NEET 2024]
aAbscisic acid
bAuxin
cGibberellin
dCytokinin
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Q10
PYQ
Auxin is used by gardeners to prepare weed- free lawns. But no damage is caused to grass as auxin - [NEET 2024]
acan help in cell division in grasses, to produce growth
bpromotes apical dominance
cpromotes abscission of mature leaves only
ddoes not affect mature monocotyledonous plants
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Q11
PYQ
If the apical bud has been removed then we observe
aMore lateral branches
bmore axillary roots
cPlant growth stops
dFlowering stops
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Q12
PYQ
One of the commonly used plant growth hormone in tea plantation is
aZeatin
bABA
cAuxin
dEthylene
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Q13
PYQ
Which hormone promotes internode/petiole elongation in deep water rice plants?
aKinetin
bEthylene
c2,4-D
dGA3
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Q14
PYQ
Spraying of which of the following phytohormone on juvenile conifers helps in hastening the maturity period, that leads to early seed production? [NEET 2023]
aGibberellic Acid
bZeatin
cAbscisic Acid
dIndole-3-butyric Acid
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Q15
PYQ
F. Skoog observed that callus proliferated from the internodal segments of tobacco stem when auxin was supplied with one of the following except:
aExtract of Vascular tissues
bCoconut milk
cAbscisic acid
dYeast Extract
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Q16
PYQ
Formation of interfascicular cambium from fully developed parenchyma cells is an example for [NEET 2024]
aMaturation
bDifferentiation
cRedifferentiation
dDedifferentiation
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Q17
PYQ
Which of the following plant growth regulators is used as herbicide ?
[Re-NEET 2026]
a
2,4-D
b
Kinetin
c
Abscisic acid
d
Gibberellin
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Q18
PYQ
Given below are some statements about plant growth regulators. A. All GAs are acidic in nature. B. Auxins are antagonists to GAs. C. Zeatin was isolated from coconut milk. D. Ethylene induces flowering in Mango. E. Abscisic acid induces parthenocarpy. Choose the correct set of statements from the option given below:
[Re-NEET 2024]
a
A , C , D
b
B , E
c
A , B , C
d
B, D,E
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Q19
PYQ
Heterophyllous development in response to environment is an example of which of the following phenomena?
[NEET 2026]
a
Dedifferentiation
b
Elasticity
c
Redifferentiation
d
Plasticity
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Q20
PYQ
Auxin is used by gardeners to prepare weed-free lawns. But no damage is caused to grass as auxin
[NEET 2024]
a
can help in cell division in grasses, to produce growth
b
promotes apical dominance
c
promotes abscission of mature leaves only
d
does not affect mature monocotyledonous plants
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Q21
PYQ
Spraying sugarcane crop with which of the following plant growth regulators, increases the length of stem, thus, increasing the yield?
[NEET 2024]
a
Abscisic acid
b
Auxin
c
Gibberellin
d
Cytokinin
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Q22
PYQ
Formation of interfascicular cambium from fully developed parenchyma cells is an example for
[NEET 2024]
a
Maturation
b
Differentiation
c
Redifferentiation
d
Dedifferentiation
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Q23
PYQ
Auxin is used by gardeners to prepare weed-free lawns. But no damage is caused to grass as auxin -
[NEET 2024]
a
can help in cell division in grasses, to produce growth
b
promotes apical dominance
c
promotes abscission of mature leaves only
d
does not affect mature monocotyledonous plants
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Q24
PYQ
Given below are some statements about plant growth regulators. A. All GAs are acidic in nature. B. Auxins are antagonists to GAs. C. Zeatin was isolated from coconut milk. D. Ethylene induces flowering in Mango. E. Abscisic acid induces parthenocarpy. Choose the correct set of statements from the option given below:
[Re-NEET 2024]
a
A, C, D
b
B, E
c
A, B, C
d
B, D, E
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Q25
PYQ
F. Skoog observed that callus proliferated from the internodal segments of tobacco stem when auxin was supplied with one of the following except:
[Re-NEET 2024]
a
Extract of Vascular tissues
b
Coconut milk
c
Abscisic acid
d
Yeast Extract
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Q26
PYQ
Which one of the following is not a characteristic of plant cells in the phase of elongation?
[NEET 2026]
a
Increased vacuolation
b
Large conspicuous nuclei
c
Cell enlargement
d
New cell wall deposition
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Q27
PYQ
Length of the stem at time 0 is 20 cm. The arithmetic growth rate is 30 cm per day. What is the length of the stem at the end of the 7th day?
[Re-NEET 2026]
a
50 cm
b
170 cm
c
230 cm
d
460 cm
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Q28
PYQ
Formation of interfascicular cambium from fully developed parenchyma cells is an example of
[NEET 2024]
a
Maturation
b
Differentiation
c
Redifferentiation
d
Dedifferentiation
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Q29
PYQ
Which of the following plant growth regulators promotes internode elongation prior to flowering in cabbage ?
[Re-NEET 2026]
a
Abscisic acid
b
Gibberellin
c
Indole butyric acid
d
Ethephon
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Q30
PYQ
Spraying sugarcane crop with which of the following plant growth regulators, increases the length of stem, thus, increasing the yield?
[NEET 2024]
a
Abscisic acid
b
Auxin
c
Gibberellin
d
Cytokinin
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Q31
PYQ
F. Skoog observed that callus proliferated from the internodal segments of tobacco stem when auxin was supplied with one of the following except:
a
Extract of Vascular tissues
b
Coconut milk
c
Abscisic acid
d
Yeast Extract
🔒
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Q32
PYQ
Which of the following statements is not correct?
a
Phase of cell elongation of plant cells is characterized by increased vacuolation.
b
Cells in the meristematic phase of growth exhibit abundant plasmodesmatal connections.
c
Plant growth is generally determinate.
d
Plant growth is measurable.
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Q33
PYQ
The process of growth is maximum during
[NEET 2020]
a
Lag phase
b
Senescence
c
Dormancy
d
Log phase
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Q34
PYQ
Which of the following is not an inhibitory substance governing seed dormancy?
[NEET 2020]
a
Gibberellic acid
b
Abscisic acid
c
Phenolic acid
d
Para-ascorbic acid
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Q35
PYQ
Match List-I with List-II.
List-I
List-II
(A)
Auxin
(I)
Promotes female flower formation in cucumber
(B)
Gibberellin
(II)
Overcoming apical dominance
(C)
Cytokinin
(III)
Increase in the length of grape stalks
(D)
Ethylene
(IV)
Promotes flowering in pineapple
Choose the correct answer from the options given below:
a
A-II, B-I, C-IV, D-III
b
A-IV, B-III, C-II, D-I
c
A-I, B-III, C-IV, D-II
d
A-III, B-II, C-I, D-IV
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Q36
PYQ
The plant hormone used to destroy weeds in a field is
[NEET 2021]
a
IBA
b
IAA
c
NAA
d
2, 4-D
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Q37
PYQ
The process of growth is maximum during
a
Lag phase
b
Senescence
c
Dormancy
d
Log phase
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Q38
PYQ
Which hormone promotes internode/petiole elongation in deep water rice plants?
[NEET 2023]
a
Kinetin
b
Ethylene
c
2,4-D
d
GA3
🔒
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Q39
PYQ
Which hormone promotes internode/petiole elongation in deep water rice?
a
2, 4-D
b
\({\mathrm{GA}}_{3}\)
c
Kinetin
d
Ethylene
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Q40
PYQ
Who coined the term 'Kinetin'?
a
Darwin
b
Went
c
Kurosawa
d
Skoog and Miller
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Q41
PYQ
Inhibitory substances in dormant seeds cannot be removed by subjecting seeds to:
[Re-NEET 2020]
a
Nitrate
b
Ascorbic acid
c
Chilling conditions
d
Gibberellic acid
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Q42
PYQ
In tissue culture experiments, leaf mesophyll cells are put in a culture medium to form callus. This phenomenon may be called as
a
Senescence
b
Differentiation
c
Dedifferentiation
d
Development
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Q43
PYQ
Name the plant growth regulator which upon spraying on sugarcane crop, increases the length of stem, thus increasing the yield of sugarcane crop.
a
Gibberellin
b
Ethylene
c
Abscisic acid
d
Cytokinin
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Q44
PYQ
The site of perception of light in plants during photoperiodism is
[NEET 2021]
a
leaf
b
shoot apex
c
stem
d
axillary bud.
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Q45
PYQ
Match the following concerning the activity/function and the phytohormone involved.
1.
Fruit ripener
(i)
Abscisic acid
2.
Herbicide
(ii)
GA3
3.
Bolting agent
(iii)
2, 4-D
4.
Stress hormone
(iv)
Ethephon
Select the correct option from following:
a
1 - (iii), 2 - (iv), 3 - (ii), 4 - (i)
b
1 - (iv), 2 - (iii), 3 - (ii), 4 - (i)
c
1 - (iv), 2 - (ii), 3 - (i), 4 - (iii)
d
1 - (ii), 2 - (iii), 3 - (iv), 4 - (i)
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Q46
PYQ
Name the plant growth regulator which upon spraying on sugarcane crop, increases the length of stem, thus increasing the yield of sugarcane crop.
[NEET 2020]
a
Cytokinin
b
Gibberellin
c
Ethylene
d
Abscisic acid
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Q47
PYQ
Spraying of which of the following phytohormone on juvenile conifers helps in hastening the maturity period, that leads to early seed production?
a
Abscisic Acid
b
Indole-3-butyric Acid
c
Gibberellic Acid
d
Zeatin
🔒
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Q48
PYQ
The plant hormone used to destroy weeds in a field is
a
NAA
b
2, 4-D
c
IBA
d
IAA
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Q49
PYQ
In relation to Gross primary productivity and Net primary productivity of an ecosystem, which one of the following statements is correct?
a
Gross primary productivity is always less than Net primary productivity
b
Gross primary productivity is always more than Net primary productivity
c
Gross primary productivity and Net primary productivity are one and same
d
There is no relationship between Gross primary productivity and Net primary productivity
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Q50
PYQ
Plants follow different pathways in response to environment or phase of life to form different kinds of structures. This ability is called
a
Flexibility
b
Plasticity
c
Maturity
d
Elasticity
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Q51
PYQ
The phenomenon which is influenced by auxin and also played a major role in its discovery
a
Phototropism
b
Root initiation
c
Gravitropism
d
Apical Dominance
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