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What is Phototropism?

Phototropism is the orientation of plant growth in response to light stimulus. There are two types of phototropism. When a plant grows toward the light source, that development is referred to as “positive phototropism.” The opposite—growth away from the light source—is “negative phototropism.”

Why Does Phototropism Occur?

  Positive phototropism is the most common type of light-related plant orientation. It occurs simply because the plant is attempting to get as much light exposure as possible to facilitate photosynthesis. However, some vines display negative phototropism as they seek out large, shaded objects to climb.