Fig 1.
The eight spectral treatments and characteristics.
Blue, green and red values are percent of total PPF (400 to 700 nm). UV-A is percent of total PPF. Phytochrome photoequilibrium (PPE) was determined as described by Sager et al. (1988). Symbols correspond to the color for each treatment and shape represents the two PPFs (200 and 500 μmol m-2 s-1), which are associated with DLIs of 11.5 and 29 mol m-2 d-1. Symbol shape and color are consistent in all figures.
Fig 2.
Spectral distributions of all eight LED treatments.
Treatments include three types of white LEDs (cool, warm and neutral), red + blue (RB), red + green + blue (RGB) LEDs, and the narrow band red, green, and blue LEDs. Variation in spectral distribution between the 200 and 500 μmol m-2 s-1 treatments was negligible.
Fig 3.
Overhead view of cucumber plants at harvest.
Includes all eight LED treatments at both light intensities arranged from low to high BL fraction. There were four plants per treatment and three replicates per study. Note the difference in coloration with the green and red treatments at the 500 PPF level (DLI = 29 mol m-2 d-1).
Fig 4.
The effect of percent blue light on dry mass (DM) gain for seven species under two PPFs.
Note scale break for percent BL between 30 and 60. Also note two-fold scale increase for DM in radish and pepper. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the four treatments with comparable green and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 5.
The effect of percent green light on dry mass (DM) gain for seven species under two PPFs.
Note two-fold scale increase for DM in radish and pepper. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the three treatments with comparable blue and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 6.
The effect of percent blue light on leaf area index (LAI) for seven species under two PPFs.
Note scale break for percent BL between 30 and 60. Also note two fold scale increase for pepper. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the four treatments with comparable green and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 7.
The effect of percent green light on leaf area index (LAI) for seven species under two PPFs.
Note two fold scale increase for pepper. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the three treatments with comparable blue and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 8.
The effect of percent blue light on net assimilation for seven species under two PPFs.
Note scale break for percent BL between 30 and 60. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the four treatments with comparable green and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 9.
The effect of percent green light on net assimilation for seven species under two PPFs.
Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the three treatments with comparable blue and red wavelengths for each PPF. When significant, p-values and percent change are shown. Regression line includes the RB, RBG and warm white treatments for each PPF. When significant, p-values and percent change are shown.
Fig 10.
The effect of percent blue light on stem length for seven species under two PPFs.
Note scale break for percent BL between 30 and 60. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the four treatments with comparable green and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 11.
The effect of percent green light on stem length for seven species under two PPFs.
Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the three treatments with comparable blue and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 12.
The effect of percent blue light on petiole length for seven species under two PPFs.
Note scale break for percent BL between 30 and 60. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the four treatments with comparable green and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 13.
The effect of percent green light on petiole length for seven species under two PPFs.
Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the three treatments with comparable blue and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 14.
The effect of percent blue light on specific leaf area for seven species under two PPFs.
Note scale break for percent BL between 30 and 60. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the four treatments with comparable green and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 15.
The effect of percent green light on specific leaf area for seven species under two PPFs.
Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the three treatments with comparable blue and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 16.
The effect of percent blue light on chlorophyll concentration for seven species under two PPFs.
Note scale break for percent BL between 30 and 60. Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the four treatments with comparable green and red wavelengths for each PPF. When significant, p-values and percent change are shown.
Fig 17.
The effect of percent green light on chlorophyll concentration for seven species under two PPFs.
Each data point shows the mean and standard deviation of three replicate studies for each species (n = 3). Some error bars are smaller than the symbol size. See Fig 1 for symbol color and shape legend. To minimize confounding spectral effects the regression line includes only the three treatments with comparable blue and red wavelengths for each PPF. When significant, p-values and percent change are shown.