The study looked at how young and older leaves of Japanese yew plants respond to high sunlight. Young leaves had lower chlorophyll, photosynthesis, and light tolerance. Both types of leaves showed reduced photosynthesis under strong light, but young leaves were more affected. Young leaves also had lower efficiency in using light for photosynthesis. They had less ability to protect themselves from too much light, leading to damage. The plants tried to protect themselves by changing certain pigments, but young leaves were less successful. Overall, young leaves were more vulnerable to damage from high light due to their lower ability to use carbon dioxide for photosynthesis and protect themselves from excess light.