Figure 1.

Spectral distributions of four light treatments consisted of blue (B; 400-500 nm), green (G; 500-600 nm), red (R; 600-700 nm), and far-red (FR; 700-800 nm) photons delivered by light-emitting diodes. Two total photon flux densities (TPFD; 400 to 800 nm) were used: μmol m^-2 s^-1 (A) and 300 μmol m^-2 s^-1 (B). Two light spectral treatments were denoted based on the percentage of FR photons in TPFD: 0%FR (B₁₅G₁₅R₁₂₀) and 20%FR (B₁₅G₁₅R₉₀FR₃₀) under TPFD of 150 μmol m^-2 s^-1 and 0%FR (B₃₀G₃₀R₂₄₀) and 20%FR (B₃₀G₃₀R₁₈₀FR₆₀) under TPFD of 300 μmol m^-2 s^-1. The subscript after each waveband indicates its photon flux density in μmol m^-2 s^-1.