The study looked at how different amounts of copper affect the way sweet potatoes use sunlight to grow. Sweet potatoes were grown in water with varying copper levels for nine days. Higher copper levels improved one part of the plant's photosynthesis system, but made another part less efficient. Sweet potatoes with medium copper levels were best at protecting themselves from too much sunlight. Overall, too much copper can reduce how well sweet potatoes use sunlight, but also make them better at using a specific type of light.