Early-maturing peach leaves turn red in summer due to changes in photosynthesis and chlorophyll fluorescence. The study found that red leaves had higher photosynthetic efficiency and were better adapted to high temperatures and strong sunlight compared to green leaves. The red color was due to anthocyanin accumulation, which increased the share of photochemical reactions in the leaves. However, red leaves had lower ability to safely dissipate excess light energy compared to green leaves.