Table 1. Spectral characteristics of sole-source lighting treatments.

Six sole-source lighting treatments were delivered from mint white (MW), red (R), blue (B), and green (G) light-emitting diodes (LEDs) at total photosynthetic photon flux density (PPFD) = 160 μmol∙m⁻²∙s⁻¹. The subscript values after each LED type indicate the percentages of the total PPFD delivered from each LED type.

Radiation treatment	% Ba	% G	% R	FRb	R:FRc	PSSd	YPFDe
MW100	15	59	26	6	8	0.84	141
MW75R25	11	45	44	4	17	0.87	142
MW45R55	7	27	66	3	35	0.88	145
MW25R75	4	16	80	2	57	0.88	146
B15R85	15	0	85	1	130	0.88	147
B20G40R40	20	40	40	1	108	0.87	134

^aPercentage of B (400−500 nm), G (500−600 nm), and R (600−700 nm) radiation among total PPFD (400−700 nm).

^bPhoton flux integral of FR (700−800 nm) radiation in μmol∙m⁻²∙s⁻¹.

^cR:FR: Ratio of photon flux integral of R (600−700 nm) and FR (700−800 nm) radiation.

^dPSS: phytochrome photostationary state following Sager et al. [12].

^eYPFD: Yield photon flux density, which is the product of TPFD and relative quantum efficiency (in μmol∙m⁻²∙s⁻¹) based on McCree [1] and Sager et al. [12].