Please refer to Plant Growth and Development Class 11 Biology Important Questions with answers below. These solved questions for Chapter 15 Plant Growth and Development in NCERT Book for Class 11 Biology have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these solved problems properly as these will help them to get better marks in your class tests and examinations. You will also be able to understand how to write answers properly. Revise these questions and answers regularly. We have provided Notes for Class 11 Biology for all chapters in your textbooks.

Important Questions Class 11 Biology Chapter 15 Plant Growth and Development

Objective Questions

Question. Auxin and Cytokinin are antagonistic in which of the following function?
(a) Cell division
(b) Phototropism
(c) Apical dominance
(d) Geotropism

Question. Kinetin, a modified adenine (purine) was discovered from
(a) The autoclaved herring sperm DNA
(b) Coconut milk
(c) Com-Kernel
(d) Fungus

Question. Zeatin was extracted for the first time from
(a) Maize
(b) Cocunut
(c) Fungus
(d) Autoclaved herring sperm

Question. Cytokinin helps in delay of leaf senescence by
(a) Increasing more water absorption by root
(b) Increasing rate of translocation of organic solutes
(c) Promoting nutrients mobilization
(d) Formation of adventitious buds

Question. A. C₂H₄ promotes leaf senescence
B. C₂H₄ speeds the ripening of fruits
C. C₂H₄ promotes horizontal growth of seeding and swelling of axis
D. C₂H₄ promotes male flowers in cucumber thereby increasing the yield
Which one is false?
(a) All
(b) A and E
(c) B and D
(d) E

Question. Which hormone is used to initiate flowering and synchronizing fruit set in pineapple?
(a) C₂H₂
(b) C₂H₄
(c) GA₃
(d) IAA

Question. The below diagram shows the stages of seed germination

Now identify, A, B, C and D respectively
(a) Plumule, Cotyledon, Epicotyl and Hypocotyl
(b) Radicle, Cotyledon, Epicotyl and Hypocotyl
(c) Mesocotyl, Cotyledon, Epicotyl and Hypocotyl
(d) Root hair, Cotyledon, Epicotyl and Hypocotyl

Question. A. “Y” hormone induces flowering in mango and also promotes rapid internode / petiole elongation in deep water plants and hence helps in keeping leaves or upper part of shoot above the water surface
B. “X” hormone promotes root growth and root hairs formation
C. “Z” hormone inhibits the seed germination, increases the tolerance of plant to various stresses, play important role in seed development, maturation and dormancy
Identify the correct names of hormones
(a) Y=ABA; X=Auxin; Z=GA
(b) Z=GA; X=Auxin; Y= C₂H₄
(c) Y=Auxin; X= C₂H₄;;Z=GAA
(d) Y= C₂H₄; X= C₂H₄; Z=ABA

Question. Ethephon hastens the fruit ripening in tomatoes and apple, accelerates abscission in flowers and fruits Above statement indicates that ethephon must release
(a) ABA
(b) C₂H₄
(c) IAA
(d) GA₇

Question. Which of the following is incorrect?
(a) Any PGR has diverse physiological effects on plants
(b) Diverse PGRs manifest similar effect
(c) PGRs may act synergistically and antagonistically
(d) none

Question. Go through the following experiment and observe the result, Now identify plants (P-I, II and III)

(a) P-I = Long day plant, P-II = Short day plant, P-III = Day neutral plant
(b) P-I = Short day plant, P-II = Long day plant, P-III = Day neutral plant
(c) P-I = Short day plant, P-II = Short day plant, P-III = Day neutral plant
(d) P-I = Long day plant, P-II = Long day plant, P-III = Day neutral plant

Question. Given below is a graph drawn on the parameters of growth versus time A, B, C respectively represent

(a) Exponential phase, log phase and steady state phase
(b) Steady state phase, lag phase and log phase
(c) Log phase, steady state phase and logarithmic phase
(d) Log phase, lag phase and steady state phase

Question. Germination takes place when the
(a) previously dormant embryo is activated.
(b) cotyledons emerge above the ground.
(c) hypocotyl or epicotyl emerges above the ground.
(d) vascular tissues begin to transport fluids.

Question. In arithmetic growth rate, when length of the organ is plotted against time, the nature of graph curve will be —
(a) linear
(b) sigmoidal
(c) parabolic
(d) hyperbolic

Question. In which of the following process, the cell loose their protoplasm to form tracheary element?
(a) Dedifferentiation
(b) Redifferentiation
(c) Differentiation
(d) Plasticity

Question. Which one of the following is chemically identical to ABA?
(a) Indole-3-acetic acid
(b) Kinetin
(c) Dormin
(d) 2, 4-D

Question. Which of the following is not an influence of auxins?
(a) Apical dominance
(b) Parthenocarpy
(c) Phototropism
(d) Fruit ripening

Question. Gibberellin was first extracted from —
(a) Gibberella fujikuroi
(b) algae
(c) bacteria
(d) roots of higher plants

Question. Hormone responsible for bolting is —
(a) IAA
(b) kinetin
(c) ABA
(d) GA

Question. Which of the following is not a function of cytokinin?
(a) Promotes apical dominance.
(b) Promotes chloroplast development.
(c) Promotes movement of nutrients.
(d) Delay leaf senescence.

Statement Type Question

Question. Which of the following statement is not correct about the conditions for plant growth?
(a) Oxygen helps in releasing metabolic energy essential for growth activities.
(b) Nutrients are required by plants for the synthesis of protoplasm and act as source of energy.
(c) Light and gravity affect certain stages of growth.
(d) Water oxidizes glucose to provide energy.

Question. Which of the following statement is correct regarding ethylene?
(a) It delayes senescence.
(b) It decreases the respiration rate during fruit ripening.
(c) It breaks seed and bud dormancy.
(d) It inhibits flowering in mango.

Assertion/Reason Type Questions

In the following questions, a statement of Assertion is followed by a statement of Reason.
(a) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
(b) If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
(c) If Assertion is true but Reason is false.
(d) If both Assertion and Reason are false.

Question. Assertion : Cytokinins are antisenescent.
Reason : Effect of cytokinins is antagonistic to ethylene.

Question. Assertion : Auxins help to prevent fruits and leaves drop at early stages. 
Reason : Auxins promote the abscission of older mature leaves and fruits.

Question. Assertion : Decapitation is widely used in tea plantation and hedge-making.
Reason : Removal of shoot tips usually results in the growth of lateral buds.

Critical Thinking Type Questions

Question. Plant hormone which is translocated to other parts for growth of the plant is
(a) indole-3-acetic acid
(b) gibberellins
(c) cytokinins
(d) none of these

Question. Which one of the following promotes the abscission of older mature leaves and fruits?
(a) Indole compounds
(b) adenine derivatives
(c) derivatives of carotenoids
(d) gaseous hormones

Question. Which one of the following hormone is used to eradicate dicotyledonous weeds, but does not have its effect on mature monocotyledonous plants?
(a) 2, 4-D
(b) IAA
(c) NAA
(d) IBA

Question. Which of the following acids is a derivative of terpenes?
(a) Gibberellic acid
(b) Naphthalene acetic acid
(c) Abscissic acid
(d) ‘a’ and ‘c’

Question. Which of the following hormones causes fruits like apple to elongate and improve its shape?
(a) GA
(b) ABA
(c) NAA
(d) 2, 4D

Question. Which form of gibberellic acid is used to speed up the malting process in brewing industry?
(a) GA₁
(b) GA₂
(c) GA₃
(d) None of these

Question. Ethylene is not directly applied in the field as a gas due to its high diffusion rate. Which compound is used to overcome this limitation?
(a) Ethephon
(b) Agent orange
(c) Benzaldehyde
(d) 2, 4, 5-T

Question. Abscisic acid is a
(a) gaseous hormone
(b) stress hormone
(c) volatile hormone
(d) liquid-gas mixture

Question. A long day plant flowers only if exposed to a light period
(a) more than its critical day length.
(b) less than its critical day length.
(c) equal to its critical day length.
(d) slightly less than its critical day length.

Question. One set (I) of a plant was grown at 12 hours day and 12 hours night period cycles and it flowered while in the other set (II) night phase was interrupted by flash of light and it did not produce flower. Under which one of the following categories will you place this plant (Set II)?
(a) Long day
(b) Darkness neutral
(c) Day neutral
(d) Short day

Question. Which of the following effects is brought about by gibberellins but not by auxins?
(a) Inhibition of leaf abscission.
(b) Stimulation of cambial activity.
(c) Stimulation of fruit development.
(d) Breaking of dormancy in leaf buds.