1. Control and coordination in plants is carried out by ____________.
A) Nervous system
B) Hormones
C) Brain
D) Both nerves and hormones
Answer: B
Explanation: Plants lack nerves/brain; chemical messengers (phytohormones) coordinate activities.
2. Plant hormones are also called ____________.
A) Neurotransmitters
B) Growth regulators
C) Enzymes
D) Cytokinins
Answer: B
Explanation: Phytohormones regulate growth, movement, and responses in plants.
3. How many major plant hormones are known?
A) Two
B) Three
C) Five
D) Seven
Answer: C
Explanation: Main plant hormones are auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
4. Which plant hormone is responsible for cell elongation?
A) Gibberellin
B) Auxin
C) Cytokinin
D) Ethylene
Answer: B
Explanation: Auxins promote cell elongation, especially in shoots.
5. The natural auxin found in plants is____________.
A) IAA (Indole-3-acetic acid)
B) GA₃
C) ABA
D) Kinetin
Answer: A
Explanation: IAA is the first and most common naturally occurring auxin.
6. Which hormone promotes seed dormancy?
A) Auxin
B) Cytokinin
C) Abscisic acid
D) Gibberellin
Answer: C
Explanation: ABA induces dormancy and inhibits germination.
7. Which hormone breaks seed dormancy and promotes germination?
A) Auxin
B) Gibberellin
C) Ethylene
D) Cytokinin
Answer: B
Explanation: Gibberellins stimulate seed germination and enzyme production.
8. Cytokinins primarily promote____________.
A) Root growth
B) Shoot elongation
C) Cell division
D) Leaf fall
Answer: C
Explanation: Cytokinins regulate cytokinesis (cell division).
9. Which hormone promotes fruit ripening?
A) Ethylene
B) Auxin
C) Cytokinin
D) Gibberellin
Answer: A
Explanation: Ethylene is a gaseous hormone responsible for ripening.
10. Which hormone is used commercially to ripen bananas and mangoes?
A) Auxin
B) Cytokinin
C) Ethylene
D) Gibberellin
Answer: C
Explanation: Ethylene gas and its releasers are used for artificial ripening.
11. Which hormone promotes abscission (leaf fall)?
A) Auxin
B) Gibberellin
C) Abscisic acid
D) Cytokinin
Answer: C
Explanation: ABA causes abscission of leaves, fruits, and flowers.
12. “Stress hormone” in plants is____________.
A) Auxin
B) Gibberellin
C) Abscisic acid
D) Ethylene
Answer: C
Explanation: ABA helps plants survive stress (drought, salinity).
13. Which hormone promotes apical dominance?
A) Auxin
B) Gibberellin
C) Cytokinin
D) Ethylene
Answer: A
Explanation: Auxins in the shoot tip suppress lateral bud growth.
14. Which hormone promotes lateral bud growth?
A) Auxin
B) Cytokinin
C) Gibberellin
D) ABA
Answer: B
Explanation: Cytokinins counteract auxin, stimulating lateral buds.
15. Which hormone causes bolting in plants like cabbage?
A) Auxin
B) Cytokinin
C) Gibberellin
D) Ethylene
Answer: C
Explanation: Gibberellins induce sudden stem elongation (bolting).
16. Which plant hormone is a gas at room temperature?
A) Auxin
B) Ethylene
C) Cytokinin
D) Gibberellin
Answer: B
Explanation: Ethylene is the only gaseous plant hormone.
17. Hormone responsible for parthenocarpy (seedless fruit formation)____________.
A) Gibberellin
B) Auxin
C) Cytokinin
D) Ethylene
Answer: B
Explanation: Auxins induce fruit formation without fertilization.
18. The first discovered plant hormone was____________.
A) Auxin
B) Gibberellin
C) Cytokinin
D) Ethylene
Answer: A
Explanation: Auxin (IAA) was discovered by F.W. Went in 1928.
19. Which hormone delays senescence (aging) of leaves?
A) Auxin
B) Gibberellin
C) Cytokinin
D) ABA
Answer: C
Explanation: Cytokinins prevent yellowing and aging of leaves.
20. Hormone responsible for stomatal closure during water stress____________.
A) Auxin
B) Cytokinin
C) Gibberellin
D) Abscisic acid
Answer: D
Explanation: ABA signals guard cells to close stomata during drought.
21. Which hormone regulates senescence and abscission?
A) ABA
B) Auxin
C) Cytokinin
D) Gibberellin
Answer: A
Explanation: Abscisic acid controls aging and leaf fall.
22. Which hormone induces flowering in pineapples?
A) Auxin
B) Ethylene
C) Cytokinin
D) ABA
Answer: B
Explanation: Ethylene is used to induce uniform flowering in pineapples.
23. Which hormone promotes fruit ripening in tomatoes?
A) Auxin
B) Gibberellin
C) Ethylene
D) Cytokinin
Answer: C
Explanation: Ethylene accelerates ripening in climacteric fruits like tomato.
24. Which hormone can overcome apical dominance by promoting lateral buds?
A) Gibberellin
B) Cytokinin
C) Auxin
D) Ethylene
Answer: B
Explanation: Cytokinins antagonize auxin action, encouraging branching.
25. Gibberellins were first discovered in____________.
A) Wheat
B) Rice
C) Pea
D) Corn
Answer: B
Explanation: Gibberellins were discovered in rice plants infected by fungus Gibberella fujikuroi.
26. The directional movement of a plant part in response to an external stimulus is called____________.
A) Nastic movement
B) Tropic movement
C) Growth movement
D) Seismonasty
Answer: B
Explanation: Tropic movements are directional and depend on the stimulus direction.
27. Movement of plant in response to light is called____________.
A) Phototropism
B) Geotropism
C) Hydrotropism
D) Thigmotropism
Answer: A
Explanation: Phototropism is movement towards or away from light.
28. Bending of stem towards light is____________.
A) Negative phototropism
B) Positive phototropism
C) Negative geotropism
D) Hydrotropism
Answer: B
Explanation: Shoots show positive phototropism, bending toward light source.
29. Roots grow away from light showing____________.
A) Positive phototropism
B) Negative phototropism
C) Positive geotropism
D) Chemotropism
Answer: B
Explanation: Roots show negative phototropism since they grow away from light.
30. Movement of plant in response to gravity is____________.
A) Phototropism
B) Geotropism
C) Chemotropism
D) Hydrotropism
Answer: B
Explanation: Geotropism (gravitropism) is the movement of plant organs due to gravity.
31. Roots show____________.
A) Positive geotropism
B) Negative geotropism
C) Neutral geotropism
D) Phototropism only
Answer: A
Explanation: Roots grow downward into soil, hence positive geotropism.
32. Stem shows____________.
A) Positive geotropism
B) Negative geotropism
C) Positive phototropism
D) Both b and c
Answer: D
Explanation: Stems grow upward (negative geotropism) and towards light (positive phototropism).
33. Movement of plants towards water is called____________.
A) Hydrotropism
B) Geotropism
C) Phototropism
D) Thigmotropism
Answer: A
Explanation: Roots show hydrotropism, growing towards moisture.
34. Movement of plant in response to chemical stimulus is____________.
A) Chemotropism
B) Geotropism
C) Hydrotropism
D) Thigmotropism
Answer: A
Explanation: Chemotropism is movement due to chemicals, e.g., pollen tube towards ovule.
35. Growth of pollen tube towards ovule is an example of____________.
A) Phototropism
B) Geotropism
C) Chemotropism
D) Hydrotropism
Answer: C
Explanation: Pollen tube grows towards ovule due to chemical attractants.
36. Movement of plants in response to touch is called____________.
A) Chemotropism
B) Thigmotropism
C) Phototropism
D) Hydrotropism
Answer: B
Explanation: Thigmotropism is seen in tendrils, coiling around support due to touch.
37. Coiling of pea tendrils around support is____________.
A) Phototropism
B) Thigmotropism
C) Hydrotropism
D) Geotropism
Answer: B
Explanation: Tendrils coil in response to touch stimulus.
38. Shoots show which type of phototropism?
A) Positive
B) Negative
C) Neutral
D) None
Answer: A
Explanation: Shoots grow towards light source (positive phototropism).
39. Roots show which type of phototropism?
A) Positive
B) Negative
C) Both positive and negative
D) None
Answer: B
Explanation: Roots usually grow away from light.
40. Which type of geotropism is shown by stem?
A) Positive
B) Negative
C) Neutral
D) None
Answer: B
Explanation: Stem grows opposite to gravitational pull.
41. Example of positive chemotropism is____________.
A) Coiling of tendril
B) Pollen tube growth
C) Root growth towards water
D) Stem towards light
Answer: B
Explanation: Pollen tube grows towards ovule due to chemicals.
42. Movement of root towards nutrients in soil is____________.
A) Hydrotropism
B) Chemotropism
C) Thigmotropism
D) Phototropism
Answer: B
Explanation: Roots grow towards regions of higher nutrient concentration.
43. The stimulus in phototropism is____________.
A) Gravity
B) Water
C) Light
D) Chemical
Answer: C
Explanation: Phototropism occurs due to response towards light.
44. The stimulus in geotropism is____________.
A) Light
B) Gravity
C) Water
D) Chemical
Answer: B
Explanation: Geotropism occurs due to gravitational force.
45. The stimulus in hydrotropism is____________.
A) Water
B) Light
C) Gravity
D) Chemical
Answer: A
Explanation: Hydrotropism occurs when roots sense water in soil.
46. Which hormone is mainly responsible for tropic movements?
A) Gibberellin
B) Cytokinin
C) Auxin
D) Ethylene
Answer: C
Explanation: Unequal distribution of auxin causes bending in tropic responses.
47. Bending of plant towards light is due to____________.
A) Equal auxin distribution
B) More auxin on shaded side
C) More auxin on lighted side
D) Loss of auxin
Answer: B
Explanation: Auxin accumulates on shaded side → more elongation → bending towards light.
48. Positive hydrotropism is shown by____________.
A) Shoots
B) Tendrils
C) Roots
D) Leaves
Answer: C
Explanation: Roots grow towards water source.
49. Negative thigmotropism is shown by____________.
A) Tendrils
B) Roots
C) Stem
D) Pollen tube
Answer: B
Explanation: Roots avoid objects in soil → show negative thigmotropism.
50. Tropic movements are always____________.
A) non-directional
B) Directional
C) Random
D) Spontaneous
Answer: B
Explanation: Tropic movements depend on the direction of stimulus.
51. The movement in plants which is non-directional and independent of stimulus direction is called____________.
A) Tropic movement
B) Nastic movement
C) Growth movement
D) Hydrotropism
Answer: B
Explanation: Nastic movements are non-directional responses, e.g., opening/closing of flowers.
52. Folding of Mimosa pudica (touch-me-not plant) leaves when touched is____________.
A) Thigmotropism
B) Seismonasty
C) Phototropism
D) Hydrotropism
Answer: B
Explanation: This is a nastic movement due to touch/vibration stimulus.
53. Opening and closing of flowers in response to light is____________.
A) Photonasty
B) Phototropism
C) Hydrotropism
D) Thigmonasty
Answer: A
Explanation: Photonasty is light-induced non-directional movement.
54. Sleep movement in plants (closing of leaves at night) is____________.
A) Photonasty
B) Nyctinasty
C) Geotropism
D) Thigmotropism
Answer: B
Explanation: Nyctinasty is leaf movement in response to day-night rhythm.
55. Nastic movements are usually controlled by____________.
A) Nervous system
B) Plant hormones and turgor pressure
C) Muscles
D) Electrical impulses
Answer: B
Explanation: Changes in auxin distribution and water pressure in cells cause nastic movements.
56. Thigmonasty refers to____________.
A) Movement due to gravity
B) Movement due to touch
C) Movement due to water
D) Movement due to chemicals
Answer: B
Explanation: Thigmonasty = touch-sensitive non-directional movement.
57. Which plant shows thigmonastic movements?
A) Cuscuta
B) Mimosa pudica
C) Hydrilla
D) Sunflower
Answer: B
Explanation: Leaves fold instantly on touch (thigmonastic).
58. Nyctinasty in plants is regulated by____________.
A) Light and darkness (circadian rhythm)
B) Touch
C) Gravity
D) Temperature
Answer: A
Explanation: Nyctinasty occurs due to daily biological clock changes.
59. The opening of tulip and crocus flowers in response to temperature is____________.
A) Photonasty
B) Thermonasty
C) Nyctinasty
D) Seismonasty
Answer: B
Explanation: Thermonasty = non-directional movement due to temperature.
60. The downward drooping of leaves due to loss of turgor pressure is____________.
A) Tropism
B) Nastic movement
C) Wilting
D) Geotropism
Answer: C
Explanation: Wilting occurs due to water loss and reduced turgidity.
61. Which of the following is NOT an example of nastic movement?
A) Opening of dandelion flowers in sunlight
B) Drooping of Mimosa pudica leaves
C) Root growing towards water
D) Closing of lotus flowers at night
Answer: C
Explanation: That is hydrotropism (directional), not nastic.
62. The movement of guard cells controlling stomata opening is an example of____________.
A) Thigmonasty
B) Photonasty
C) Turgor movement
D) Chemotropism
Answer: C
Explanation: Stomatal movement depends on water pressure in guard cells.
63. Seismonasty in Mimosa pudica is caused by____________.
A) Rapid cell elongation
B) Sudden change in turgor pressure
C) Hormonal changes
D) Photosynthesis
Answer: B
Explanation: Water shifts in pulvini cells → leaflets fold instantly.
64. Sleep movement of legumes is an example of____________.
A) Photonasty
B) Nyctinasty
C) Thermonasty
D) Thigmonasty
Answer: B
Explanation: Leaf folding during night is nyctinasty.
65. In Mimosa pudica, the swollen base of petiole that shows rapid movement is called____________.
A) Pulvinus
B) Node
C) Internode
D) Tendril
Answer: A
Explanation: Pulvinus acts like a motor organ, changing turgor pressure.
66. Photonasty in flowers occurs due to____________.
A) Unequal auxin distribution
B) Light intensity changes
C) Nutrient deficiency
D) CO₂ accumulation
Answer: B
Explanation: Flower opening/closing is non-directional, driven by light intensity.
67. Which movement is growth-independent?
A) Tropic
B) Nastic
C) Geotropism
D) Phototropism
Answer: B
Explanation: Nastic movements depend on turgor pressure, not growth.
68. Example of thermonastic movement is____________.
A) Pollen tube growth
B) Leaf folding of Mimosa
C) Opening of tulip flowers in warmth
D) Tendril coiling
Answer: C
Explanation: Non-directional flower opening due to temperature.
69. Venus flytrap captures insects by____________.
A) Geotropism
B) Thigmonasty
C) Chemotropism
D) Thermonasty
Answer: B
Explanation: Touch stimulus triggers closure of trap lobes.
70. Rapid plant movements are usually caused by____________.
A) Hormonal growth
B) Turgor changes in cells
C) DNA mutation
D) Cell division
Answer: B
Explanation: Sudden turgor shifts in specialized cells cause quick movements.
71. In nyctinasty, leaflets close at____________.
A) Day
B) Night
C) Midday
D) Morning
Answer: B
Explanation: Leaflets fold or droop during night (sleep movement).
72. The opening of morning glory flowers is due to____________.
A) Phototropism
B) Photonasty
C) Thigmotropism
D) Seismonasty
Answer: B
Explanation: Morning glories open in response to light intensity.
73. Thigmonasty in insectivorous plants helps in____________.
A) Photosynthesis
B) Nitrogen capture
C) Water transport
D) Reproduction
Answer: B
Explanation: Venus flytrap and sundew catch insects to supplement nitrogen.
74. Nastic movements are called non-directional because____________.
A) They do not depend on stimulus
B) They do not depend on stimulus direction
C) They occur only at night
D) They occur only in roots
Answer: B
Explanation: Nastic responses (e.g., flower opening) are independent of direction of stimulus.
75. Which type of movement is involved in closing of lotus flowers at dusk?
A) Tropic movement
B) Photonastic movement
C) Geotropism
D) Seismonasty
Answer: B
Explanation: Flower closing/opening due to light is photonasty.
76. Which plant hormone is used to induce uniform flowering in pineapple?
A) Auxin
B) Cytokinin
C) Ethylene
D) Gibberellin
Answer: C
Explanation: Ethylene induces synchronized flowering in pineapple plantations.
77. Farmers spray auxins on tomato plants to____________.
A) Kill insects
B) Prevent leaf fall
C) Produce seedless fruits
D) Increase water absorption
Answer: C
Explanation: Auxins induce parthenocarpy (seedless fruit formation).
78. “Turgor movements” in plants are powered by____________.
A) Hormones only
B) Movement of water in and out of cells
C) Sunlight directly
D) Respiration alone
Answer: B
Explanation: Sudden turgor pressure changes drive rapid movements like Mimosa pudica.
79. The opening and closing of stomata are controlled by____________.
A) Root pressure
B) Guard cell turgidity
C) Xylem vessels
D) Phloem
Answer: B
Explanation: Stomata open/close depending on water pressure inside guard cells.
80. Which movement helps insectivorous plants like Drosera (sundew) trap insects?
A) Tropic movement
B) Thigmonasty
C) Photonasty
D) Thermonasty
Answer: B
Explanation: Tentacles of sundew bend due to touch stimulus when insects land.
81. The hormone responsible for leaf abscission is____________.
A) Auxin
B) Gibberellin
C) Abscisic acid
D) Cytokinin
Answer: C
Explanation: ABA accelerates leaf and fruit fall.
82. Apical dominance in plants is due to____________.
A) Cytokinins
B) Gibberellins
C) Auxins
D) Ethylene
Answer: C
Explanation: Auxins at the shoot tip suppress lateral bud growth.
83. Removal of apical bud leads to____________.
A) Reduced growth
B) Increased lateral branching
C) Death of plant
D) Leaf abscission
Answer: B
Explanation: Without auxin from apical bud, cytokinins promote lateral bud growth.
84. Which movement is shown by sunflower heads following the sun?
A) Thigmotropism
B) Photonasty
C) Heliotropism
D) Hydrotropism
Answer: C
Explanation: Sunflower heads show solar tracking (heliotropism).
85. Which hormone was discovered from a fungus Gibberella fujikuroi?
A) Auxin
B) Gibberellin
C) Ethylene
D) Cytokinin
Answer: B
Explanation: Gibberellins were first identified in rice plants infected by this fungus.
86. Which plant hormone is used as a weed killer (herbicide)?
A) 2,4-D (a synthetic auxin)
B) Gibberellin
C) Cytokinin
D) Ethylene
Answer: A
Explanation: 2,4-D kills broad-leaved weeds without harming cereal crops.
87. The “anti-aging hormone” in plants is____________.
A) Auxin
B) Gibberellin
C) Cytokinin
D) Ethylene
Answer: C
Explanation: Cytokinins delay senescence (aging) of leaves.
88. Phototropism was first studied by____________.
A) Charles Darwin
B) Gregor Mendel
C) Frits Went
D) Karl Landsteiner
Answer: A
Explanation: Darwin showed coleoptiles bend towards light due to auxin redistribution.
89. F.W. Went demonstrated auxin action using____________.
A) Coleoptile tip of oat seedling
B) Root of pea plant
C) Sunflower
D) Mimosa pudica
Answer: A
Explanation: Went isolated auxin from oat coleoptile tips.
90. Which plant hormone is widely used in tissue culture for cell division?
A) Auxin
B) Cytokinin
C) Ethylene
D) Gibberellin
Answer: B
Explanation: Cytokinins induce rapid cell division in culture media.
91. Which hormone is called the “stress hormone” in plants?
A) Auxin
B) Abscisic acid
C) Ethylene
D) Cytokinin
Answer: B
Explanation: ABA helps plants tolerate drought, salinity, and stress.
92. The response of roots towards water is____________.
A) Geotropism
B) Hydrotropism
C) Chemotropism
D) Photonasty
Answer: B
Explanation: Roots grow towards water source (positive hydrotropism).
93. The Venus flytrap’s movement is an example of____________.
A) Tropism
B) Nastic movement
C) Growth movement
D) Hydrotropism
Answer: B
Explanation: Closure of trap is non-directional and touch-induced (thigmonasty).
94. Plant movement that occurs in response to external stimulus but is growh-dependent is____________.
A) Tropic movement
B) Nastic movement
C) Turgor movement
D) Seismonasty
Answer: A
Explanation: Tropic movements involve differential growth of cells.
95. The hormone commonly used to induce fruit ripening artificially is____________.
A) Auxin
B) Ethylene
C) Gibberellin
D) ABA
Answer: B
Explanation: Ethylene accelerates ripening in fruits like banana and mango.
96. In phototropism, bending occurs due to____________.
A) Equal auxin distribution
B) Auxin accumulation on shaded side
C) Auxin accumulation on illuminated side
D) Lack of auxin
Answer: B
Explanation: Auxin promotes cell elongation more on shaded side → bending towards light.
97. Which plant hormone stimulates stem elongation and leaf expansion?
A) Auxin
B) Cytokinin
C) Gibberellin
D) ABA
Answer: C
Explanation: Gibberellins promote elongation and leaf expansion.
98. In plant movements, pulvini are____________.
A) Photosynthetic cells
B) Swollen leaf bases acting as motor organs
C) Root hairs
D) Guard cells
Answer: B
Explanation: Pulvini control leaf movements in plants like Mimosa pudica.
99. A plant showing both positive geotropism and positive hydrotropism is____________.
A) Stem
B) Root
C) Tendril
D) Flower
Answer: B
Explanation: Roots grow downward (gravity) and towards water.
100. Which one is NOT a plant hormone?
A) Auxin
B) Cytokinin
C) Gibberellin
D) Hemoglobin
Answer: D
Explanation: Hemoglobin is a respiratory pigment in animals, not a plant hormone.