UPSC CAPF AC 2019 Paper

In phototropism a plant bends or grows directionally in response to light. Positive phototropism is growth towards a light source; negative phototropism is growth away from light. Shoots, or above ground parts of plants, generally display positive phototropism—they bend toward the light. This response helps the green parts of the plant get closer to a source of light energy, which can then be used for photosynthesis.