The researchers studied how a decrease in rainfall affects the leaf pigments and reflectance of Quercus aliena var. acuteserrata. They found that chlorophyll b was most sensitive to the rainfall reduction, while carotenoids were less affected. The 550 nm wavelength was the most sensitive to pigment changes. A new index, SR750,550, was developed to measure these changes. The study showed strong relationships between this index and chlorophyll and carotenoid content. Overall, the research highlights how changes in rainfall can impact the pigments and reflectance of leaves in this tree species.