NEET Biology Multiple Choice Questions – Plant Growth And Development

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Plant Growth And Development Multiple Choice Questions And Answers

Question 1. The condition of suspended growth due to external environmental conditions is called

  1. Dormancy
  2. Rest
  3. Quiescence
  4. All of these

Answer: 4. All of these

Question 2. Seed dormancy in tomato seeds is due to

  1. Impermeable seed coat
  2. Immature embryo
  3. Presence of ferulic acid in pulp
  4. Abscisic acid in pulp

Answer: 2. Immature embryo

Question 3. A method to break the dormancy of seed by subjecting to low and high temperatures is called

  1. Scarification
  2. Pressure chamber method
  3. Stratification
  4. Impaction

Answer: 3. Stratification

Question 4. Which does not happen during seed germination?

  1. Emergence of radical
  2. Increase in the rate of respiration
  3. Hydrolysis of stored polysaccharides and proteins
  4. Photosynthesis by cotyledons

Answer: 4. Photosynthesis by cotyledons

Question 5. Real growth is

  1. Protoplasmic growth
  2. Cell wall growth
  3. Growth in size
  4. Growth in volume

Answer: 1. Protoplasmic growth

Question 6. Growth in plant organs is

  1. Qualitative and extrinsic
  2. Quantitative and intrinsic
  3. Qualitative and intrinsic
  4. Quantitative and extrinsic

Answer: 3. Qualitative and intrinsic

Question 7. The point in the S-shaped growth curve where growth is maximum is called

  1. Inflection point
  2. Compensation point
  3. Extinction point
  4. Deflection point

Answer: 3. Extinction point

Question 8. The exponential phase in growth is characterized by

  1. Enlargements of cells
  2. Constant increase in growth rate
  3. Maturation of cells
  4. Both (1) and (2)

Answer: 4. Both (1) and (2)

Question 9. Which of the following is not a growth-measuring instrument?

  1. Auxanometer
  2. Crescograph
  3. Horizontal microscope
  4. Clinostat

Answer: 1. Auxanometer

Question 10. The plant growth is regulated by

  1. Climatic factor
  2. Growth hormones
  3. Both (1) and (2)
  4. None of these

Answer: 2. Growth hormones

Question 11. The growth in plants differs from the growth in animals

  1. Being localized and indefinite
  2. Being indefinite
  3. Having indefinite lifespan
  4. Having a definite lifespan

Answer: 1. Being localized and indefinite

Question 12. The scientist who suspected the presence of some growth substances was

  1. Linnaeus
  2. Mendel
  3. Charles Darwin
  4. Robert Brown

Answer: 3. Charles Darwin

Question 13. If an etiolated stem could be first saturated with auxin by spraying and then exposed to a streak of light from one side, it will

  1. Bend toward the light
  2. Bend away from the light
  3. Grow straight upward
  4. Be prevented from growing

Answer: 2. Bend away from the light

Question 14. The plant hormone which is basic in nature is

  1. Auxin
  2. Gibberellin
  3. Cytokinin
  4. Abscisic acid

Answer: 2. Gibberellin

Question 15. Which is not a physiological effect of auxins?

  1. Cell elongation
  2. Development of parthenocarpic fruits
  3. Prevention of abscission of leaves and fruits
  4. Reversal of genetic dwarfism

Answer: 2. Development of parthenocarpic fruits

Question 16. Transport of auxins is

  1. Polar
  2. Diffuse
  3. Through xylem
  4. Through phloem

Answer: 4. Through phloem

Question 17. The movement shown by a plant kept in a phototropic chamber is due to

  1. Differential synthesis of hormones
  2. Differential translocation of hormones
  3. None of these
  4. Both (1) and (2)

Answer: 2. Differential translocation of hormones

Question 18. Sprouting of potatoes can be prevented in storage by

  1. CH4
  2. GA3
  3. MH
  4. CK

Answer: 2. GA3

Question 19. A phytotron is a device by which

  1. Electron flow is measured
  2. Mutations are induced in plants
  3. The wind velocity is measured
  4. Plants are grown in a controlled environment

Answer: 2. Mutations are induced in plants

Question 20. Apical dominance in higher plants is due to

  1. The balance between auxins and cytokinins
  2. Enzyme activity
  3. Carbohydrates and nitrogen ratio
  4. Incorrect photoperiod

Answer: 2. Enzyme activity

Question 21. Cholodny-Went theory is related with

  1. Phototropism
  2. Photomorphogenesis
  3. Photorespiration
  4. Photosynthesis

Answer: 2. Photomorphogenesis

Question 22. Gibbane ring skeleton in structure and production of hydrolytic enzymes in barley endosperm is a characteristic of

  1. Cytokinin
  2. Auxins
  3. Gibberellins
  4. Ethylene

Answer: 3. Gibberellins

Question 23. The Avena curvature test and dwarf maize test are bioassays of respectively,

  1. Auxins and gibberellins
  2. GA and CK
  3. Auxins and CK
  4. IAA and ethylene

Answer: 1. Auxins and gibberellins

Question 24. Specific property attributed to GA is

  1. Shortening of genetically tall plants
  2. Elongation of genetically dwarf plants
  3. Rooting or stem cuttings
  4. Promotion of leaf and fruit fall

Answer: 2. Elongation of genetically dwarf plants

Question 25. The synthesis of α-amylase in certain cereals is stimulated by

  1. IAA
  2. GA
  3. OK
  4. ABA

Answer: 4. ABA

Question 26. Cytokinins are considered a part of

  1. t-RNA
  2. r-RNA
  3. DNA
  4. Vascular tissues

Answer: 2. r-RNA

Question 27. An anti-ageing plant hormone from the following is

  1. IAA
  2. GA3
  3. Zeatin
  4. C2H4

Answer: 1. IAA

Question 28. The delay of senescence or Richmond-Lang effect is a physiological effect of

  1. IAA
  2. OK
  3. GA
  4. C2H4

Answer: 2. OK

Question 29. The number of female flowers can be increased by the application of

  1. IAA
  2. C2H4
  3. OK
  4. All of these

Answer: 1. IAA

Question 30. The triple response is shown by the hormone

  1. Ethylene
  2. CK
  3. 2, 4-D
  4. GA3

Answer: 4. GA3

Question 31. Which of the following is an anti-gibberellin as well as a stress hormone?

  1. ABA
  2. CK
  3. NAAM
  4. 2,4-D

Answer: 2. CK

Question 32. Which is not true for abscisic acid?

  1. Acts as an anti-transpirant
  2. Synthesized in chloroplast from carotenoids
  3. Increases stress tolerance in plants
  4. Induces epinasty of leaves and flowers

Answer: 1. Acts as an anti-transpirant

Question 33. CH2=CH2 is mainly responsible for

  1. Formation of root hair
  2. Formation of nodes
  3. Ripening of fruits
  4. Formation of intemodes

Answer: 4. Formation of internodes

Question 34. For flowering, the critical dark period should always be exceeded in

  1. Long day plants
  2. Short day plants
  3. Day-neutral plants
  4. All types of plants

Answer: 4. All types of plants

Question 35. Photoperiodic stimulus is perceived by

  1. Meristematic cells
  2. Leaves
  3. Flowers
  4. Seeds

Answer: 1. Meristematic cells

Question 36. Which of the following statements does not characterize photoperiodism?

  1. Mediated by florigen hormone.
  2. Conversion of shoot apex into reproductive apex.
  3. Red light is stimulatory in SDP, LDP, and DNP for flowering.
  4. The number of correct photoperiodic induction may be 1-25.

Answer: 2. Conversion of shoot apex into reproductive apex.

Question 37. Find the odd one (with respect to photoperiod) from the following.

  1. Rice
  2. Cosmos
  3. Chrysanthemum
  4. Larkspur

Answer: 4. Larkspur

Question 38. Hypothetical florigen could be produced prematurely in day plants by exposing it to

  1. Shortening light period
  2. Red light during the night
  3. Extending dark period
  4. Far-red light

Answer: 2. Red light during the night

Question 39. The acquisition of the ability to flower by chilling treatment is called

  1. Vernalization
  2. Yarovization
  3. Springification
  4. All of these

Answer:  3. Springification

Question 40. Which is not a requirement of vernalization?

  1. Aerobic condition
  2. Moisture
  3. Low temperature
  4. Differentiated tissues

Answer: 1. Aerobic condition

Question 41. The hormone that can replace the long days and low-temperature requirement for flowering in some plants is

  1. Gibberellin
  2. Cytokinin
  3. Vemalin
  4. Ethylene

Answer: 2. Cytokinin

Question 42. Senescence is

  1. Terminal irreversible phase of aging
  2. Combined deteriorative processes in mature plant
  3. A period between complete maturity and final death of an organ
  4. All of these

Answer: 2. Combined deteriorative processes in mature plant

Question 43. Shoot or top senescence occurs in

  1. Rice
  2. Gladiolus
  3. Mango
  4. Dalbergia

Answer: 2. Gladiolus

Question 44. The abscission zone is characterized by

  1. Presence of callose plugs
  2. The presence of a distinct layer
  3. Activity of celluloses and pectinases
  4. All of these

Answer: 1. Presence of callose plugs

Question 45. In which layer of the abscission zone, the breakdown of cells occur?

  1. Gonidial layer
  2. Protective layer
  3. Separation layers
  4. All of these

Answer: 4. All of these

Question 46. The leaves of Mimosa pudica (sensitive plant) droop down on touch because

  1. The plant has a nervous system
  2. The leaves are very tender
  3. The leaves are injured
  4. The turgor pressure of the leaf base changes

Answer: 3. The leaves are injured

Question 47. Plants growing under prolonged water stress conditions develop the phenomenon of leaf area adjustment which is

  1. Shortening of plastochron
  2. Reduction of leaf surface area
  3. Shortening of intermodal length
  4. Shedding of older leaves

Answer: 4. Shedding of older leaves

Question 48. The seasonal activity of cambium is promoted by

  1. Proline
  2. Auxin
  3. Ethylene
  4. Abscisic acid

Answer: 1. Proline

Question 49. Find the odd one (with respect to the cause of seed dormancy)

  1. Amaranthus
  2. Capsella
  3. Ginkgo
  4. Trigonella

Answer: 4. Trigonella

Question 50. The pigment concerned with various photomorphogenic processes in plants has

  1. Open tetrapyrrolic structure
  2. Absorption spectra different from that of chlorophyll
  3. Positive effects on membrane permeability
  4. All of these

Answer: 3. Positive effects on membrane permeability

Question 51. Plant hormones are

  1. Growth regulators
  2. Growth promoters
  3. Growth inhibitors
  4. None of above

Answer: 1. Growth regulators

Question 52. The most common auxin is

  1. GA
  2. ABA
  3. Kinetin
  4. IAA

Answer: 4. IAA

Question 53. Gibberellin promotes cell division and elongation in

  1. Leaves
  2. Roots
  3. Shoots
  4. All of these

Answer: 4. All of these

Question 54. The deteriorative processes in plants that naturally terminate their functional life are collectively called

  1. Wilting
  2. Abscission
  3. Plasmolysis
  4. Senescence

Answer: 4. Senescence

Question 55. Which of the following is

  1. Auxin
  2. ABA
  3. Ethylene gas
  4. Cytokinin

Answer: 3. Ethylene gas

Question 56. The induction of flowering treatment is called

  1. Vernalization
  2. Photoperiodism
  3. Cryobiology
  4. Chronology

Answer: 1. Vernalization

Question 57. Plant growth is

  1. Limited
  2. Unlimited
  3. Diffused
  4. Both (1) and (2)

Answer: 4. Both (1) and (2)

Question 58. Hormones produced during leaf fall is

  1. IAA
  2. ABA
  3. Florigen
  4. Kinetin

Answer: 2. ABA

Question 59. Climacteric fruit shows

  1. High respiration rate at ripening
  2. Sudden change in taste
  3. Sudden change in color and shape
  4. None of the above

Answer: 1. High respiration rate at ripening

Question 60. Phytochrome is present in

  1. Vascular cryptogams
  2. Prokaryotes
  3. Brain cell
  4. Kidney cell

Answer: 1. Vascular cryptogams

Question 61. Genetically, dwarf plants can be converted into a plant of normal height with the application of

  1. Auxin
  2. Gibberellin
  3. Cytokinins
  4. Auxin

Answer: 2. Gibberellin

Question 62. A phytohormone involved in the de novo synthesis of α-amylase in germinating seeds is

  1. Auxin
  2. Gibberellin
  3. Ethylene
  4. Cytokinin

Answer: 2. Gibberellin

Question 63. Phytochrome is responsible for

  1. Photosynthesis
  2. Flowering
  3. Fruit formation
  4. Respiration

Answer: 2. Flowering

Question 64. Which of the following is a gaseous hormone?

  1. Ethylene
  2. Cytokinin
  3. Both ethylene and auxin
  4. Gibberellin

Answer: 1. Ethylene

Question 65. The pineapple which under natural conditions is difficult to blossom has been made to produce fruits throughout the year by the application of

  1. IAA, IBA
  2. NAA, 2,4-D
  3. Phenyl mercuric acid
  4. Cytokinins

Answer: 1. IAA, IBA

Question 66. Most of the plants are seasonal due to

  1. Photoperiodism
  2. Phototropism
  3. Photosynthesis
  4. Photolysis

Answer: 1. Photoperiodism

Question 67. Certain chemical substances having profound effects on plant growth are called

  1. Catalytic agents
  2. Phytohormones
  3. Enzymes
  4. Compost

Answer: 2. Phytohormones

Question 68. Phytochrome was discovered by

  1. W. Went
  2. Gamer and Allard
  3. F.F. Blackman
  4. Borthwick and Hendricks

Answer: 4. Borthwick and Hendricks

Question 69. The activity of α-amylase in the endosperm of barley germinating seed is induced by

  1. Ethylene
  2. Cytokinin
  3. IAA
  4. Gibberellin

Answer: 4. Gibberellin

Question 70. A pigment concerned with floral induction is

  1. Florigen
  2. Chlorophyll
  3. Plastocyanin
  4. Phytochrome

Answer: 4. Phytochrome

Question 71. Gibberellins were first discovered in the fungal genus

  1. Mucor
  2. Rhizopus
  3. Agaricus
  4. Fusarhim

Answer: 4. Fusarhim

Question 72. The presence of auxins in a solution could be tested based on

  1. Avena sativa stem tip test
  2. Carbon tetrachloride test
  3. Iodine test
  4. Defoliation test

Answer: 1. Avena sativa stem tip test

Question 73. An auxanometer is used to measure

  1. Length
  2. Width
  3. Depth
  4. Growth

Answer: 4. Growth

Question 74. The pigment sensitivity for red and far-red light is

  1. Chlorophyll
  2. Phytochrome
  3. Cytochrome
  4. Carotene

Answer: 2. Phytochrome

Question 75. The hormone that breaks seed dormancy is

  1. Auxin
  2. Gibberellin
  3. Ethylene
  4. Cytokinin

Answer: 2. Gibberellin

Question 76. Which one of the following is not a synthetic auxin?

  1. 2,4-D
  2. 2,4,5-T
  3. NAA
  4. IAA

Answer: 4. IAA

Question 77. Which plant hormone causes fruit ripening?

  1. IAA
  2. Cytokinin
  3. Ethylene
  4. GA

Answer: 3. Ethylene

Question 78. Which hormone is responsible for apical growth?

  1. IAA
  2. ABA
  3. GA
  4. All of these

Answer: 1. IAA

Question 79. Abscisic acid controls

  1. Cell elongation and cell wall formation
  2. Shoot elongation
  3. Leaf fall and dormancy
  4. Cell division

Answer: 3. Leaf fall and dormancy

Question 80. Which hormone is used to induce ripening in bananas?

  1. Cytokinin
  2. Ethylene
  3. ABA
  4. GA3

Answer: 2. Ethylene

Question 81. Which among the following is a synthesis plant hormone?

  1. IAA
  2. GA
  3. 2,4-D
  4. ABA

Answer: 3. 2,4-D

Question 82. Richmond-Lang effect is shown by

  1. Auxins
  2. Sugars
  3. Zeatin
  4. Gibberellins

Answer: 3. Zeatin

Question 83. Ethylene gas is used for

  1. Growth of plants
  2. Delaying fruit abscission
  3. Ripening of fruits
  4. Stopping the leaf abscission

Answer: 3. Ripening of fruits

Question 84. An auxanometer is used to detect

  1. Respiration
  2. Transpiration
  3. Plant movement
  4. Growth

Answer: 4. Growth

Question 85. Which of the following plant hormones is extracted from fungus?

  1. Ethylene
  2. Gibberellin
  3. Cytokinin
  4. 2,4-D

Answer: 2. Gibberellin

Question 86. The highest concentration of auxin is found in

  1. Root and shoot tips
  2. Leaves and fruits
  3. Mid stem portion
  4. None of these

Answer: 1. Root and shoot tips

Question 87. Ethylene is used for

  1. Decreasing the senescence
  2. Increasing the heights of the stem
  3. Ripening of fruits
  4. Prevention of leaf fall

Answer: 3. Ripening of fruits

Question 88. The movement of the pollen tube is called

  1. Chemotropism
  2. Thermotaxis
  3. Their monastic
  4. Hydrotropism

Answer: 1. Chemotropism

Question 89. Phytotron is

  1. A controlled condition chamber for plants
  2. Leaf culture process
  3. Special culture of seeds
  4. Root culture process

Answer: 1. A controlled condition chamber for plants

Question 90. Phytochrome occurs in two forms. Its stable form is

  1. Pfr form
  2. Pr form
  3. Both forms
  4. None of these

Answer: 2. Pr form

Question 91. Which pigment is responsible for flowering in plants?

  1. Phytochrome
  2. Cytochrome
  3. Anthocyanin
  4. Xanthophyll

Answer: 1. Xanthophyll

Question 92. The process of vernalization can be induced by

  1. Cytokinin
  2. Auxin
  3. Phototropin
  4. GA

Answer: 4. GA

Question 93. Which of the following plant is LDP?

  1. Xanthium
  2. Soyabean
  3. Wheat
  4. Tobacco

Answer: 3. Wheat

Question 94. Phototropism is due to the hormone

  1. IAA
  2. GA
  3. 2-4 D
  4. Cytokinin

Answer: 1. IAA

Question 95. Photoperiodism affects

  1. Vegetative growth
  2. Internode elongation
  3. Seed germination
  4. Reproductive growth

Answer: 4. Reproductive growth

Question 96. Apical dominance is not affected by

  1. Indoleacetic acid
  2. Gibberellins
  3. Indoleacetaldehyde
  4. Indolebutyric acid

Answer: 2. Gibberellins

Question 97. The activity of α-amylase in the endosperm of barley germinating seed is induced by

  1. Ethylene
  2. Cytokinin
  3. IAA
  4. Gibberellin

Answer: 4. Gibberellin

Question 98. A pigment concerned with both floral induction and seed germination is

  1. Florigen
  2. Chlorophyll
  3. Plastocyanin
  4. Phytochrome

Answer: 4. Phytochrome

Question 99. Which of the following may be the substitute of photoperiodism?

  1. Humidity
  2. Temperature
  3. Mineral nutrients
  4. Soil moisture

Answer: 2. Temperature

Question 100. Phytohormine commonly called stress hormone is

  1. Auxin
  2. Abscisic acid
  3. Gibberellin
  4. Cytokinins

Answer: 2. Abscisic acid

Question 101. Fruit ripening can be hastened by treatment with

  1. LAA
  2. Florigen
  3. Ethylene
  4. Cytokinin

Answer: 3. Ethylene

Question 102. Opening of floral bud is an example of

  1. Induced movement
  2. Hyponastic movement
  3. Epinastic movement
  4. Cleistogamous movement

Answer: 3. Hyponastic movement

Question 103. Pruning of plants promotes branching because the axillary buds get sensitized to

  1. Ethylene
  2. Gibberellin
  3. Cytokinin
  4. IAA

Answer: 3. Cytokinin

Question 104. Cell elongation in intermodal regions of the green plants takes place due to

  1. Ethylene
  2. Indole acetic acid
  3. Cytokinin
  4. Gibberellins

Answer: 4. Gibberellins

Question 105. One set of a plant was grown at 12-hour day and 12-hour night period cycles and it flowered. In the other set, the night phase was interrupted by a flash of light and it did not flower. Under which one of the following categories will you place this plant?

  1. Short day
  2. Long day
  3. Darkness neutral
  4. Day-neutral

Answer: 1. Short day

Question 106. The maximum growth rate occurs in

  1. Exponential phase
  2. Stationary phase
  3. Senescent phase
  4. Lag phase

Answer: 1. Exponential phase

Question 107. The ability of the Venus flytrap to capture insects is due to

  1. Chemical stimulation by the prey
  2. A passive process requiring no special ability on the part of the plant
  3. Specialized “muscle-like” cells
  4. Rapid turgor pressure changes

Answer: 2. A passive process requiring no special ability on the part of the plant

Question 108. Why is vivipary an undesirable character for annual crop plants?

  1. It reduces the vigor of the plant.
  2. The seeds cannot be stored under normal conditions for the next season.
  3. The seeds cannot exhibit long dormancy.
  4. It adversely affects the fertility of the plant.

Answer: 2. The seeds cannot be stored under normal conditions for the next season.

Question 109. Gibberellins can promote seed germination because of their influence on

  1. Rate of cell division
  2. Production of hydrolyzing enzymes
  3. Synthesis of abscisic acid
  4. Absorption of water through hard seed coat.

Answer: 2. Production of hydrolyzing enzymes

Question 110. IAA mainly inhibits the growth of

  1. Root
  2. Leaf
  3. Shoot
  4. Generally whole plant

Answer: 1. Root

Question 111. Movement due to external stimuli is known of

  1. Autonomic movement
  2. Paratonic movement
  3. Amoeboid movement
  4. Excretory movement

Answer: 2. Paratonic movement

Question 112. How does pruning help in making the hedge dense?

  1. The apical shoot grows faster after pruning.
  2. It releases wound hormones.
  3. It induces the differentiation of new shoots from the rootstock.
  4. It frees axillary buds from apical dominance.

Answer: 4. It frees axillary buds from apical dominance.

Question 113. Parthenocarpic tomato fruits can be produced by

  1. Raising the plants from vernalized seeds.
  2. Treating the plants with phenylmercury acetate.
  3. Removing androecium of flowers before pollen grains are released.
  4. Treating the plants with low concentrations of gibberellic acid and auxins.

Answer: 4. Treating the plants with low concentrations of gibberellic acid and auxins.

Question 114. An enzyme that can stimulate the germination of barley seeds is

  1. Protease
  2. Invertase
  3. α-amylase
  4. Lipase

Answer: 3. α-amylase

Question 115. The opening of floral buds into flowers is a type of

  1. Autonomic movement of growth
  2. Autonomic movement of locomotion
  3. Autonomic movement of variation
  4. Paratonic movement of growth

Answer: 1. Autonomic movement of growth

Question 116. Which one of the following pairs is not correctly matched?

  1. IAA—Cell wall elongation
  2. Abscisic acid—Stomatal closure
  3. Gibberellic acid—Leaf fall
  4. Cytokinin—Cell division

Answer: 3. Gibberellic acid—Leaf fall

Question 117. The wavelength of light that absorbed Pr form of phytochrome is

  1. 620 nm
  2. 640 nm
  3. 680 nm
  4. 720 nm

Answer: 2. 640 nm

Question 118. “Foolish seeding” disease of rice led to the discovery of

  1. IAA
  2. GA
  3. ABA
  4. 2,4-D

Answer: 2. GA

Question 119. Senescence as an active developmental cellular process in the growth and functioning of a flowering plant is indicated in

  1. Annual plants
  2. Floral parts
  3. Vessels and tracheid differentiation
  4. Leaf abscission

Answer: 4. Leaf abscission

Question 120. The importance of day length in the flowering of plants was first shown in

  1. Cotton
  2. Petunia
  3. Lemna
  4. Tobacco

Answer: 4. Tobacco

Question 121. One of the synthetic auxins is

  1. IBA
  2. NAA
  3. IAA
  4. GA

Answer: 2. NAA

Question 122. Which one of the following acids is a derivative of carotenoids?

  1. Abscisic acid
  2. Indole butyric acid
  3. Indole-3-acetic acid
  4. Gibberellic acid

Answer: 1. Abscisic acid

Question 123. Phototropic curvature is the result of uneven distribution of

  1. Cytokinins
  2. Auxin
  3. Gibberellin
  4. Phytochrome

Answer: 2. Auxin

Question 124. Photoperiodism was first characterized in

  1. Tomato
  2. Cotton
  3. Tobacco
  4. Potato

Answer: 3. Tobacco

Question 125. The coiling of garden pea tendrils around any support is an example of

  1. Thigmotropism
  2. Thermotaxis
  3. Thigmotaxis
  4. Thigmonasty

Answer: 1. Thigmotropism

Question 126. One of the commonly used plant growth hormones in tea plantations is

  1. Abscisic acid
  2. Zeatin
  3. Indole-3-acetic acid
  4. Ethylene

Answer: 2. Zeatin

Question 127. Root development is promoted by

  1. Auxin
  2. Gibberellin
  3. Ethylene
  4. Abscisic acid

Answer: 1. Auxin

Question 128. Through their effect on plant growth regulators, what is the role of temperature and light control in plants?

  1. Apical dominance
  2. Flowering
  3. Closure of stomata
  4. Fruit elongation

Answer: 2. Flowering

Question 129. Which one of the following generally acts as an antagonist to gibberellins?

  1. Zeatin
  2. Ethylene
  3. ABA
  4. IAA

Answer: 3. ABA

Question 130. Vernalization stimulates flowering in

  1. Zamikand
  2. Turmeric
  3. Carrot
  4. Ginger

Answer: 3. Carrot

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