Plant Growth and Development – Daily Practice Problem (DPP)

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🎯 NEET 2026 Daily Practice Problem (DPP)

Topic: Plant Growth and Development | 20 High-Yield MCQs

Q1. Plant growth is unique because plants retain the capacity for unlimited growth throughout their life. This is due to the presence of:

  1. Parenchyma
  2. Meristems
  3. Sclerenchyma
  4. Collenchyma
✅ View Answer & Explanation

Correct Answer: (2) Meristems
Explanation: Meristems are specialized areas in plants where cells have the capacity to divide and self-perpetuate, leading to an open form of growth.

Q2. The geometric growth curve (S-shaped) is also known as:

  1. Linear curve
  2. Sigmoid curve
  3. Parabolic curve
  4. Hyperbolic curve
✅ View Answer & Explanation

Correct Answer: (2) Sigmoid curve
Explanation: A sigmoid curve is characteristic of living organisms growing in a natural environment. It has three phases: lag, log (exponential), and stationary.

Q3. Arithmetic growth is mathematically expressed as:

  1. W_1 = W_0 e{rt}
  2. L_t = L_0 + rt
  3. L_t = L_0 \ rt
  4. W_1 = W_0 + e{rt}
✅ View Answer & Explanation

Correct Answer: (2) L_t = L_0 + rt
Explanation: In arithmetic growth, only one daughter cell continues to divide while the other differentiates. It produces a linear graph.

Q4. The process where differentiated cells regain the capacity to divide is called:

  1. Differentiation
  2. Dedifferentiation
  3. Redifferentiation
  4. Development
✅ View Answer & Explanation

Correct Answer: (2) Dedifferentiation
Explanation: Example: Formation of interfascicular cambium and cork cambium from fully differentiated parenchyma cells.

Q5. Which of the following is an example of environmental plasticity?

  1. Cotton
  2. Coriander
  3. Buttercup
  4. Larkspur
✅ View Answer & Explanation

Correct Answer: (3) Buttercup
Explanation: In Buttercup (Ranunculus), the leaves produced in air and water are different. Cotton, Coriander, and Larkspur show developmental heterophylly.

Q6. Which plant hormone was first isolated from human urine?

  1. Gibberellins
  2. Abscisic acid
  3. Auxin
  4. Ethylene
✅ View Answer & Explanation

Correct Answer: (3) Auxin
Explanation: Auxins (from Greek ‘auxein’: to grow) were first isolated from human urine. Indole-3-acetic acid (IAA) is the major natural auxin.

Q7. ‘Bakanae’ (foolish seedling) disease of rice was caused by a fungal pathogen:

  1. Gibberella fujikuroi
  2. Penicillium notatum
  3. Aspergillus niger
  4. Rhizopus nigricans
✅ View Answer & Explanation

Correct Answer: (1) Gibberella fujikuroi
Explanation: E. Kurosawa identified the symptoms of the disease were due to a substance (Gibberellic acid) secreted by this fungus.

Q8. Apical dominance is caused by:

  1. Cytokinin
  2. Abscisic acid
  3. Auxin
  4. Gibberellin
✅ View Answer & Explanation

Correct Answer: (3) Auxin
Explanation: The growing apical bud inhibits the growth of lateral (axillary) buds. Decapitation (removal of shoot tips) allows lateral buds to grow.

Q9. ‘Bolting’ (internode elongation just prior to flowering) is induced by:

  1. Ethylene
  2. Cytokinin
  3. Auxin
  4. Gibberellins
✅ View Answer & Explanation

Correct Answer: (4) Gibberellins
Explanation: Gibberellins promote bolting in rosette plants like cabbage and beet.

Q10. Zeatin was first isolated from:

  1. Coconut milk
  2. Corn kernels
  3. Human urine
  4. Rice seedlings
✅ View Answer & Explanation

Correct Answer: (2) Corn kernels
Explanation: Zeatin is a natural cytokinin. It was isolated from corn-kernels and coconut milk.

Q11. Which hormone promotes senescence and abscission of plant organs?

  1. Ethylene
  2. Abscisic acid
  3. Gibberellin
  4. Both 1 and 2
✅ View Answer & Explanation

Correct Answer: (4) Both 1 and 2
Explanation: Both Ethylene and ABA are growth inhibitors involved in aging (senescence) and shedding (abscission) of leaves/fruits.

Q12. The hormone responsible for fruit ripening is:

  1. IAA
  2. GA3
  3. ABA
  4. Ethylene
✅ View Answer & Explanation

Correct Answer: (4) Ethylene
Explanation: Ethylene is a gaseous PGR that enhances the respiration rate (respiratory climactic) during ripening.

Q13. Abscisic Acid (ABA) is also known as:

  1. Stress hormone
  2. Flowering hormone
  3. Wound hormone
  4. Fruit ripening hormone
✅ View Answer & Explanation

Correct Answer: (1) Stress hormone
Explanation: ABA increases the tolerance of plants to various kinds of stresses, notably by inducing the closure of stomata during water stress.

Q14. The site of perception of light/dark duration for photoperiodism is:

  1. Stem apex
  2. Leaves
  3. Lateral buds
  4. Roots
✅ View Answer & Explanation

Correct Answer: (2) Leaves
Explanation: Leaves perceive the photoperiod. A hormonal substance (hypothetical florigen) then migrates to the shoot apex to induce flowering.

Q15. Vernalisation refers to the promotion of flowering by:

  1. High temperature treatment
  2. Low temperature treatment
  3. High light intensity
  4. Chemical treatment
✅ View Answer & Explanation

Correct Answer: (2) Low temperature treatment
Explanation: Vernalisation prevents precocious reproductive development late in the growing season, enabling the plant to have sufficient time to reach maturity.

Q16. 2,4-D is a synthetic auxin widely used as a:

  1. Fertilizer
  2. Insecticide
  3. Herbicide
  4. Fungicide
✅ View Answer & Explanation

Correct Answer: (3) Herbicide
Explanation: 2,4-D (2,4-dichlorophenoxyacetic acid) is used to kill broad-leaved dicot weeds in monocot cereal fields.

Q17. Which PGR is used to increase the length of grape stalks?

  1. Auxin
  2. Gibberellins
  3. Cytokinin
  4. ABA
✅ View Answer & Explanation

Correct Answer: (2) Gibberellins
Explanation: Gibberellins (GAs) increase the length of the axis, hence used to increase stalks in grapes and lengthen fruits like apples.

Q18. The horizontal growth of seedlings and swelling of the axis are responses to:

  1. Gibberellin
  2. Auxin
  3. Ethylene
  4. Cytokinin
✅ View Answer & Explanation

Correct Answer: (3) Ethylene
Explanation: These are part of the ‘triple response’ of seedlings to ethylene, which also includes apical hook formation.

Q19. Which of the following plants requires a period of low temperature to flower?

  1. Wheat
  2. Sugarbeet
  3. Carrot
  4. All of the above
✅ View Answer & Explanation

Correct Answer: (4) All of the above
Explanation: Wheat (winter variety), Sugarbeet, Cabbage, and Carrots are common examples of plants showing vernalisation.

Q20. Cytokinins are primarily synthesized in:

  1. Senescent leaves
  2. Mature fruits
  3. Root tips and developing shoot buds
  4. Dry seeds
✅ View Answer & Explanation

Correct Answer: (3) Root tips and developing shoot buds
Explanation: Natural cytokinins are synthesized in regions where rapid cell division occurs.

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