Objective This study aims to explore the response patterns of the spectral characteristics (reflectance spectra, derivative spectra and three-side parameters) of the medicinal plant Tetrastigma hemsleyanum to light intensity.

Methods Two-year-old T. hemsleyanum seedlings were used as experimental materials. Five light intensity gradients were established, namely full sunlight (CK), 30% shading, 50% shading, 70% shading and 90% shading. Leaf photosynthetic pigment contents and leaf reflectance spectral characteristics were measured during the spring rapid growth period (SRP) and the summer slow growth period (SDP), respectively. The data were subjected to derivative processing and calculation of three-side parameters, and the correlations between pigment contents and spectral reflectance and three-side parameters were analyzed.

Results With the increasing shading degree, the other pigment contents generally showed an upward trend with SRP > SDP, except for Chl a/b. There were significant differences in leaf spectral reflectance and three-side parameters of T. hemsleyanum. With the decreasing light intensity, a “red shift” phenomenon occurred, and the maximum values appeared at different growth periods (70% shading at SRP and 90% shading at SDP), indicating the good growth.

Conclusion There are significant correlation between light intensity and leaf reflectance, first derivative spectra, three-side parameters and leaf photosynthetic pigment contents at different growth periods of T. hemsleyanum. Using spectroscopic methods to study the photosynthetic characteristics of T. hemsleyanum under different light intensities is a relatively advanced, effective and reliable way.