Question

Which hormone is responsible for apical dominance in plants?

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

Hint:

Auxin promotes stem elongation and maintains apical dominance. In contrast, cytokinins promote lateral bud growth and can reduce apical dominance.

Answer 1

The Correct Option is C

Concept: Apical dominance is the phenomenon in plants where the main central shoot (apical bud) suppresses the growth of lateral buds. This process ensures that the plant grows taller rather than becoming bushy. The hormone primarily responsible for this phenomenon is Auxin.

Step 1: Understand the source of auxin. Auxin is produced mainly in the apical meristem (the growing tip of the plant).

Step 2: Movement of auxin. Auxin moves downward from the apical bud to other parts of the plant.

Step 3: Effect on lateral buds. High concentrations of auxin inhibit the growth of lateral buds, thereby maintaining apical dominance.

Step 4: Experimental observation. If the apical bud is removed, the auxin supply decreases and the lateral buds begin to grow, making the plant bushier.