Layering contrasting photoselective filters improves the simulation of foliar shade

Table 10 The effects of metal halide (MH) lamps on filter spectral quality

Filter(s)	R:FR	PPE	B:G	Blue^d	Green^e	Red^f	PPF reduction^g
Filter(s)	R:FR	PPE	B:G	%
Lamp only	1.44 Aⁱ	0.80 B	0.55 E	24.0 D	63.0 C	13.0 A	–
0.60 ND^h	0.40 D	0.72 D	0.63 C	26.0 C	63.0 C	11.0 C	77.0 D
1/2 CTB	0.57 C	0.74 C	0.82 B	33.5 B	57.0 D	9.5 E	44.0 E
1/2 PG	1.24 B	0.81 A	0.35 G	17.7 F	70.3 A	12.0 B	23.7 F
0.60 ND + 1/2 CTB	0.18 F	0.64 E	0.93 A	35.3 A	56.7 D	8.0 F	87.0 B
0.60 ND + 1/2 PG	0.32 E	0.71 D	0.40 F	19.0 E	70.7 A	10.3 D	82.3 C
0.60 ND + 1/2 PG + 1/2 CTB	0.15 F	0.63 F	0.58 D	26.0 C	66.0 B	8.0 A	90.0 A

^aR:FR = 655–665/725–735
^bPPE = Phytochrome photoequilibria
^cB:G = 420–490/500–570
^dBlue = Percentage of PPF between 400 and 499 nm relative to total PPF
^eGreen = Percentage of PPF between 500 and 599 nm relative to total PPF
^fRed = Percentage of PPF between 600 and 700 nm relative to total PPF
^gPPF reduction = Percent reduction in PPF relative to full sun; PPF from MH lamps only = 30 µmol m⁻² s⁻¹
^hRosco Cinegel was used for CTB and Rosco e-colour + was used for PG and ND filters
ⁱData are presented as averages acquired on three different days: 12 June, 13 June, and 14 June 2020 at 22:00 h in a greenhouse. Means are only compared within column and were separated with Fisher’s LSD. Means followed by a common letter are not significantly different (P = 0.05)

ISSN: 1746-4811