Final answer:
Phototropism is the growth movement of plants in response to blue wavelengths of light, with positive phototropism leading to growth towards light and negative phototropism resulting in growth away from light.
Step-by-step explanation:
Phototropism and Light Color
Phototropism is the directional growth of a plant in response to light. Specifically, it is the blue wavelengths of light that trigger phototropism in plants, causing them to bend toward or away from a light source. Positive phototropism is when a plant grows towards light, which is beneficial for the photosynthetic parts like leaves and stems, while negative phototropism, also known as skototropism, is growth away from light, commonly seen in roots searching for water and nutrients underground .Photoreceptors like phototropins and other blue-light receptors, such as cryptochromes, are responsible for detecting blue light and facilitating phototropism. Even in mutant plants lacking certain pigments like carotenoids, bending toward blue light still occurs, indicating the central role of these photoreceptors. The preference of plants for blue light is a critical aspect of plant growth and development, influencing activities from stem elongation to leaf expansion.