In the context of plant light absorption patterns, ePAR and PAR refer to different ranges of the electromagnetic spectrum that are critical for photosynthesis and plant growth.

PAR (Photosynthetically Active Radiation) refers to the range of wavelengths within the visible light spectrum (400-700 nm) that plants can use for photosynthesis. It includes blue, green, and red light, which are efficiently absorbed by chlorophyll pigments in plants.

ePAR  (Effective Photosynthetically Active Radiation) is an extended concept that includes wavelengths outside the visible spectrum, such as near-infrared and ultraviolet light. (380-750) Although plants can absorb some of this light, its effectiveness in driving photosynthesis is generally lower compared to the wavelengths within the  PAR range.