What is the process in the cells of leaves caused a colour change of orange to purple?

The color change in leaves from orange to purple is primarily due to the breakdown of chlorophyll and the accumulation of other pigments. As chlorophyll degrades in response to cooler temperatures and reduced daylight, carotenoids, which produce orange hues, become more visible. Simultaneously, anthocyanins can be synthesized in response to stress factors like sunlight exposure and temperature changes, leading to purple coloration. This process reflects the plant's adaptation to environmental changes during the autumn season.