Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light have a chemical called auxin that reacts when phototropism occurs.
Phototropism. More details and explanation: Phototropism involves growth toward—or away from—a light source. Positive phototropism is growth towards a light source; negative phototropism is growth away from light. Hope this helped :)
