The study looked at how wheat leaves change as they grow. They found that the efficiency of photosynthesis in the leaves increased at first, then decreased. This efficiency was closely related to how well the leaves could turn carbon dioxide into energy. As the leaves aged, they started to lose their ability to photosynthesize efficiently, leading to damage to the plant's photosynthetic system. This research suggests that the decline in photosynthetic efficiency in older leaves is not just due to problems with the plant's energy production system, but also because of the breakdown of key enzymes involved in the process.