Plant Growth and Development NEET PYQs (2005–2026) with Solutions

10 solved Plant Growth and Development PYQs

Real NEET and AIPMT questions from this chapter, newest first. Try each one, then open the answer and the step-by-step explanation.

1. Question 1 (NEET 2026)

   NEET 2026EasyAuxins: physiological effects and uses

   Which of the following plant growth regulators is used as herbicide?

   1. AOption A: 2, 4-D
   2. BOption B: Kinetin
   3. COption C: Abscisic acid
   4. DOption D: Gibberellin

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   Correct answer: (A) 2, 4-D

   Explanation

   2, 4-D (2, 4-dichlorophenoxyacetic acid) is a synthetic auxin. NCERT states that 2, 4-D is widely used to kill dicotyledonous weeds; it does not affect mature monocotyledonous plants, so it is used to prepare weed-free lawns. Kinetin is a cytokinin (promotes cell division), abscisic acid is a growth inhibitor (stress hormone) and gibberellin promotes stem elongation; none is used as a herbicide. Hence the answer is option (A).

2. Question 2 (NEET 2026)

   NEET 2026EasyGrowth

   Which one of the following is not a characteristic of plant cells in the phase of elongation?

   1. AOption A: New cell wall deposition
   2. BOption B: Cell enlargement
   3. COption C: Increased vacuolation
   4. DOption D: Large conspicuous nuclei

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   Correct answer: (D) Large conspicuous nuclei

   Explanation

   Elongation phase is characterized by cell enlargement, vacuolation and new cell wall deposition. Large conspicuous nuclei are features of meristematic cells.

3. Question 3 (NEET 2026)

   NEET 2026MediumPlant Growth Regulators

   Match List-I with List-II Choose the correct answer from the options given below :

   1. AOption A: A-III, B-I, C-IV, D-II
   2. BOption B: A-IV, B-III, C-II, D-I
   3. COption C: A-I, B-IV, C-III, D-II
   4. DOption D: A-I, B-II, C-IV, D-III

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   Correct answer: (A) A-III, B-I, C-IV, D-II

   Explanation

   2,4-D acts as a herbicide. GA3 is used in the brewing industry. Kinetin promotes nutrient mobilisation. ABA induces stomatal closure.

4. Question 4 (NEET 2026)

   NEET 2026EasyGrowth, Differentiation and Plasticity

   Heterophyllous development in response to environment is an example of which of the following phenomena?

   1. AOption A: Redifferentiation
   2. BOption B: Elasticity
   3. COption C: Dedifferentiation
   4. DOption D: Plasticity

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   Correct answer: (D) Plasticity

   Explanation

   Plasticity is the ability of plants to alter growth patterns or structures in response to environmental conditions or developmental phases. Heterophylly is an example of plasticity.

5. Question 5 (NEET 2026)

   NEET 2026EasyGibberellins: bolting

   Which of the following plant growth regulators promotes internode elongation prior to flowering in cabbage?

   1. AOption A: Abscisic acid
   2. BOption B: Gibberellin
   3. COption C: Indole butyric acid
   4. DOption D: Ethephon

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   Correct answer: (B) Gibberellin

   Explanation

   Gibberellins promote bolting, i.e. internode elongation just prior to flowering, in plants with a rosette habit such as beet and cabbage. Abscisic acid is a growth inhibitor, indole butyric acid (an auxin) is mainly used for rooting of stem cuttings, and ethephon releases ethylene (fruit ripening, flowering in pineapple). Hence the answer is option (B).

6. Question 6 (NEET 2026)

   NEET 2026EasyArithmetic growth rate

   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 $7^{\text{th}}$ day?

   1. AOption A: 50 cm
   2. BOption B: 170 cm
   3. COption C: 230 cm
   4. DOption D: 460 cm

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   Correct answer: (C) 230 cm

   Explanation

   In arithmetic growth, the length increases by a constant amount per unit time: $$L_t = L_0 + rt$$ where $L_0$is the length at time zero,$r$the growth rate and$t$the time. Substituting$L_0 = 20$cm,$r = 30$cm per day and$t = 7$days:$$L_7 = 20 + 30 \times 7 = 20 + 210 = 230 \text{ cm}$$ Hence the answer is option (C).

7. Question 7 (NEET 2025)

   NEET 2025EasyPlant Growth Regulators

   Which one of the following phytohormones promotes nutrient mobilization which helps in the delay of leaf senescence in plants?

   1. AOption A: Ethylene
   2. BOption B: Abscisic acid
   3. COption C: Gibberellin
   4. DOption D: Cytokinin

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   Correct answer: (D) Cytokinin

   Explanation

   Cytokinins promote nutrient mobilization and delay leaf senescence in plants.

8. Question 8 (NEET 2025)

   NEET 2025MediumPlant Growth Regulators

   Read the following statements on plant growth and development. A. Parthenocarpy can be induced by auxins. B. Plant growth regulators can be involved in promotion as well as inhibition of growth. C. Dedifferentiation is a pre-requisite for re-dedifferentiation. D. Abscisic acid is a plant growth promoter. E. Apical dominance promotes the growth of lateral buds. Choose the option with all correct statements.

   1. AOption A: A, B, C only
   2. BOption B: A, C, E only
   3. COption C: A, D, E only
   4. DOption D: B, D, E only

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   Correct answer: (A) A, B, C only

   Explanation

   Auxins can induce parthenocarpy. Plant growth regulators may promote or inhibit growth. Dedifferentiation precedes redifferentiation. ABA is mainly a growth inhibitor, and apical dominance suppresses lateral bud growth.

9. Question 9 (NEET 2024)

   NEET 2024MediumPlant Growth Regulators

   Auxin is used by gardeners to prepare weed-free lawns. But no damage is caused to grass as auxin

   1. AOption A: does not affect mature monocotyledonous plants.
   2. BOption B: can help in cell division in grasses, to produce growth.
   3. COption C: promotes apical dominance.
   4. DOption D: promotes abscission of mature leaves only.

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   Correct answer: (A) does not affect mature monocotyledonous plants.

   Explanation

   Synthetic auxins selectively kill dicot weeds but do not significantly affect mature monocot grasses, allowing weed-free lawns.

10. Question 10 (NEET 2024)

    NEET 2024EasyPlant Growth Regulators

    Spraying sugarcane crop with which of the following plant growth regulators, increases the length of stem, thus increasing the yield?

    1. AOption A: Cytokinin
    2. BOption B: Abscisic acid
    3. COption C: Auxin
    4. DOption D: Gibberellin

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    Correct answer: (D) Gibberellin

    Explanation

    Gibberellins promote stem elongation in plants such as sugarcane, thereby increasing yield.