What term describes a plant growth response in which the plant grows towards or away from gravity?

What term describes a plant growth response in which the plant grows towards or away from gravity?

• A. Geotropism
• B. Phototrophism
• C. Hydrotropism
• D. Thigmotropism

Answer: (A)

Growth toward or away from gravity is geotropism (gravitropism). Gravity acts as the directional cue, so roots show positive geotropism by growing downward toward the pull of gravity, while shoots show negative geotropism by growing upward away from gravity. This movement is coordinated by uneven hormone distribution, especially auxin, which causes differential growth on the sides of the plant part so it bends in the desired direction. Other tropisms involve responses to light, water, or touch, not gravity, so they don’t describe this gravity-directed growth.

Growth toward or away from gravity is geotropism (gravitropism). Gravity acts as the directional cue, so roots show positive geotropism by growing downward toward the pull of gravity, while shoots show negative geotropism by growing upward away from gravity. This movement is coordinated by uneven hormone distribution, especially auxin, which causes differential growth on the sides of the plant part so it bends in the desired direction. Other tropisms involve responses to light, water, or touch, not gravity, so they don’t describe this gravity-directed growth.