Plant growth regulators — NEET Biology Questions

Practice 59 questions on Plant growth regulators from Plant growth and development (NCERT Class 11, Chapter 13). Free samples below — get all 59 in the app.

59 Questions Plant growth and development Class 11

Sample Questions — Plant growth regulators

Try 5 questions below from Plant growth regulators. Get all 59 in the MedicNEET app.

MCQ
Assertion (A): Ethephon is a commonly used source of ethylene in agriculture. Reason (R): Ethephon is absorbed and releases ethylene slowly inside the plant.
  • A. Both A and R are true, and R is the correct explanation of A
  • B. Both A and R are true, but R is not the correct explanation of A
  • C. A is true, but R is false
  • D. A is false, but R is true
✅ Correct Answer: A
Ethephon is widely used in agriculture; it is absorbed and releases ethylene slowly in plant tissues.
MCQ
Which PGR enhances the respiration rate during fruit ripening?
  • A. Cytokinin
  • B. Auxin
  • C. Ethylene
  • D. Gibberellin
✅ Correct Answer: C
Ethylene increases respiration rate during ripening, known as the climacteric rise.
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MCQ
Which of the following is an indole compound acting as a plant growth regulator?
  • A. Kinetin
  • B. Gibberellic acid
  • C. Indole-3-acetic acid (IAA)
  • D. Ethylene
✅ Correct Answer: C
IAA is classified as an indole compound and is a naturally occurring auxin involved in plant growth regulation.
MCQ
What is the primary function of auxins and gibberellins?
  • A. Promote dormancy
  • B. Initiate abscission
  • C. Induce stress
  • D. Promote growth activities
✅ Correct Answer: D
Auxins, gibberellins, and cytokinins belong to the group of PGRs involved in growth-promoting activities.
MCQ
Select the correct statements about auxins: I. They are found in shoot tips II. They control xylem differentiation III. They inhibit root formation IV. They induce parthenocarpy
  • A. I and IV only
  • B. I, II and IV only
  • C. II and III only
  • D. All four
✅ Correct Answer: B
Auxins occur in shoot tips, regulate vascular differentiation, and induce parthenocarpy. They promote, not inhibit, root formation.

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