The photochemical reflectance index as a measure of photosynthetic light use efficiency for plants with varying foliar nitrogen contents

A linear relationship ( r 2 =0.79, p <0.001) between the photochemical reflectance index (PRI ) and photosynthetic light use efficiency (LUE) was found for eight plant species that exhibit a significant range in foliage physical properties and nitrogen content. Experiments were conducted under artificial sunlight in a climate laboratory, using narrow-band (3.2 nm) canopy-level reflectance data to calculate the PRI, and averaged measurements of leaf net photosynthesis to obtain the LUE. If the PRI is calculated using a 10 nm bandwidth, simulating for example data from the Airborne Visible/Infrared Imaging Spectroradiometer (AVIRIS), a weaker but still significant relationship results ( r 2 =0.67, p <0.001).