Question

Which plant growth regulator is commonly used for rooting in cuttings?

• A. Gibberellin
• B. Cytokinin
• C. Auxin
• D. Ethylene

Hint:

Remember: Auxin = Root growth, Cytokinin = Shoot growth.

Answer 1

The Correct Option is C

Concept: Plant growth regulators (PGRs) are chemicals that influence plant growth and development. Different PGRs have specific functions.
Step 1: Understanding rooting in cuttings.
Rooting in cuttings refers to the formation of roots from plant parts like stems or leaves.
Step 2: Role of plant growth regulators.
Auxins promote cell elongation and are especially effective in stimulating root initiation.
Step 3: Evaluating the options.

• Gibberellin $\rightarrow$ Promotes stem elongation (incorrect)
• Cytokinin $\rightarrow$ Promotes cell division and shoot formation (incorrect)
• Auxin $\rightarrow$ Stimulates root formation in cuttings (correct)
• Ethylene $\rightarrow$ Involved in fruit ripening (incorrect)

Step 4: Additional insight.
Common synthetic auxins used for rooting include IAA (Indole-3-acetic acid), IBA (Indole-3-butyric acid), and NAA (Naphthalene acetic acid).
Step 5: Conclusion.
Thus, auxin is the plant growth regulator commonly used for rooting in cuttings.