Fig. 1

RGB light treatments designed by simplex axial mixture design. The light intensity of all treatments was the same, with different combination ratios of red, green and blue LED lights. Monochromatic light as red (R), green (G) and blue (B) lights, dichromatic light as R:G = 1:1 (RG₁₁ ), R:B = 1:1 (RB₁₁ ) and G:B = 1:1 (GB₁₁ ) and trichromatic light as R:G:B = 4:1:1 (RGB₄₁₁ ), R:G:B = 1:4:1 (RGB₁₄₁ ), R:G:B = 1:1:4 (RGB₁₁₄ ) and R:G:B = 1:1:1 (RGB₁₁₁ )