DRAW IT Indicate the response to each condition by drawing a straight seedling or one with the triple response.

Key Concepts

Phototropism

Phototropism is the growth response of a plant to light direction. Plants exhibit positive phototropism by bending towards light sources, which maximizes photosynthesis. This response is mediated by the plant hormone auxin, which redistributes on the shaded side of the plant, promoting cell elongation and causing the plant to bend.

Gravitropism

Gravitropism, also known as geotropism, is the directional growth of a plant in response to gravity. Roots typically exhibit positive gravitropism by growing downward, while stems show negative gravitropism by growing upward. This response is crucial for anchoring the plant and optimizing resource acquisition from the soil and atmosphere.

Triple Response

The triple response is a growth mechanism in plants that occurs when they encounter obstacles. It consists of three phases: slowing of stem elongation, thickening of the stem, and horizontal growth. This adaptive response allows seedlings to navigate around obstacles, ensuring they can reach light and continue growing effectively.