Final answer:
Plants respond to light through phototropism, bending toward or away from light, governed by blue wavelengths. Plant responses like gravitropism and hormones, particularly auxins, also guide their growth in response to environmental stimuli.
Step-by-step explanation:
Understanding Phototropism
Plants can sense their environment and respond accordingly. One way plants interact with their environment is through phototropism, which is a growth response to light. Blue wavelengths of light are specifically important for this process. When plants exhibit positive phototropism, they grow towards a light source. This helps the plants obtain more light for photosynthesis. Conversely, negative phototropism or skototropism occurs when they grow away from light, which we often see with roots. It was Charles Darwin who first described phototropism, noticing that the tip of the plant received the light signal, but the bending occurred at a different part of the plant, indicating that the signal had to travel.
Phototropism is not the only environmental response in plants - they also exhibit gravitropism, a growth response to gravity. Additionally, plant hormones play an integral role. Auxins, for example, affect apical dominance, root growth, and directional growth toward light.