What is the general term for growth in response to a stimulus in plants?

What is the general term for growth in response to a stimulus in plants?

• A. Tropism
• B. Phototropism
• C. Geotropism
• D. Thigmotropism

Answer: (B)

Growth in response to a stimulus in plants is called tropism. Tropisms describe directional growth toward or away from a stimulus. Phototropism is growth toward light, geotropism is growth toward gravity, and thigmotropism is growth in response to touch. The general term is needed here because the question asks for the overall category, not a specific stimulus. Mechanistically, plant hormones like auxin accumulate on the side away from the stimulus, causing cells on that side to elongate and the plant to bend toward the stimulus, which is why this broader term fits best.

Growth in response to a stimulus in plants is called tropism. Tropisms describe directional growth toward or away from a stimulus. Phototropism is growth toward light, geotropism is growth toward gravity, and thigmotropism is growth in response to touch. The general term is needed here because the question asks for the overall category, not a specific stimulus. Mechanistically, plant hormones like auxin accumulate on the side away from the stimulus, causing cells on that side to elongate and the plant to bend toward the stimulus, which is why this broader term fits best.