From ultraviolet-B to red photons: Effects of end-of-production supplemental light on anthocyanins, phenolics, ascorbic acid, and biomass production in red leaf lettuce
Fig 5
Anthocyanin index (pigment extraction analysis) (a and b) and normalized difference anthocyanin index (NDAI; image-based analysis) (c and d) in lettuce ‘Red Salad Bowl’ (a and c) and ‘Rouxai’ (b and d) grown under different spectral treatments.
Within each lettuce cultivar, different letters indicate significance at P < 0.05 among the spectral treatments. Error bars represent SE (n = 12; 6 plants per treatment x 2 blocks). The image-based NDAI showed strong linear correlation with the extraction-based anthocyanin index in both ‘Red Salad Bowl’ (e) and ‘Rouxai’ (f). See Fig 1 legend for detailed information on the spectral treatments.