Question

The hormone responsible for phototropism in plants is

• A. Cytokinin
• B. Gibberellin
• C. Auxin
• D. Abscisic acid

Answer 1

The Correct Option is C

To solve this question, we need to identify the plant hormone responsible for phototropism.

1. Understanding Phototropism:
Phototropism is the growth of a plant in response to light. It occurs when the plant's stem grows towards light sources. The hormone responsible for this directional growth is auxin.

2. Role of Auxin in Phototropism:
Auxin accumulates on the shaded side of the plant stem, causing the cells on that side to elongate. This differential growth causes the plant to bend towards the light source.

3. Evaluating the Options:

• (A) Cytokinin – Incorrect; cytokinin is involved in cell division, not phototropism.
• (B) Gibberellin – Incorrect; gibberellin is involved in growth processes like stem elongation but not specifically phototropism.
• (C) Auxin – Correct; auxin is the hormone responsible for phototropism. ✔
• (D) Abscisic acid – Incorrect; abscisic acid regulates processes like seed dormancy and stress response, not phototropism.

Final Answer:
The correct answer is (C) Auxin.