Abstract:In order to provide basic support for shade maintenance of Baccaurea ramiflora seedlings, this research used potted seedlings of the red-skinned and yellow-skinned strains of Baccaurea ramiflora as experimental materials, placed them in both outdoor and indoor conditions, and measured the diurnal variation of chlorophyll fluorescence parameters, to analyze the light adaptability of the seedlings. The diurnal variation trends of maximum photochemical efficiency(Fv/Fm), actual photosynthetic efficiency(Yield) of PS II and steady-state photochemical quenching coefficient(qP) of the two strains were basically the same, showing lower values when the light intensity was higher at noon, and higher values when the light intensity was lower in the morning and evening. The relative electron transfer efficiency(ETR) and the non-photochemical quenching coefficient(NPQ) of the two showed higher values when the light intensity was high at noon, and lower values when the light intensity was lower in the morning and evening. The yellowskinned strain was superior to the red-skinned in all parameters under different conditions, with higher light energy utilization efficiency, less heat dissipation and better electron transfer, and greater adaptability to the environment.