Copper can damage the part of plant cells responsible for photosynthesis when exposed to light. The study looked at how copper affects photosystem II in bean and pumpkin plants. They found that copper stops the plant from being able to use light properly, leading to damage. Adding an artificial electron donor helped the plant recover somewhat. Even low light levels can cause damage, and the oxygen-evolving complex in the plant cells gets affected by copper and light. Oxygen isn't needed for copper to harm the plant. If the plant is exposed to copper for a long time, its structure breaks down.