Layering contrasting photoselective filters improves the simulation of foliar shade

Table 8 Average data collected under layered color temperature blue (CTB), plus green (PG), and neutral density (ND) filters

Filter(s)	R:FR^a	PPE^b	B:G^c	PPF reduction^d	UV-A PF^e
				%	µmol m⁻² s⁻¹
1/4 PG + 1/8 CTB^f	0.76 A^g	0.68 A	0.77 J	36.7 Q	36.4 A
+ 0.30 ND	0.38 F	0.58 F	0.78 I	69.7 K	15.1 D
+ 0.60 ND	0.19 JK	0.46 L	0.80 H	86.3 E	5.2 GH
1/4 PG + 1/4 CTB	0.58 C	0.65 C	0.85 F	46.3O	34.2 AB
+ 0.30 ND	0.30 H	0.55 H	0.87 E	74.0 I	14.1 D
+ 0.60 ND	0.15 LM	0.43 N	0.89 D	88.3 C	5.3 GH
1/4 PG + 1/2 CTB	0.42 E	0.61 E	0.99 C	55.7 M	31.6 B
+ 0.30 ND	0.21 J	0.50 J	1.00 B	79.0 G	12.4 DE
+ 0.60 ND	0.11 N	0.38 P	1.03 A	90.3 B	4.8 GH
1/2 PG + 1/8 CTB	0.66 B	0.67 B	0.65 P	43.1P	23.1 C
+ 0.30 ND	0.33 G	0.57 G	0.66 O	72.3 J	10.1 EF
+ 0.60 ND	0.17 KL	0.44 M	0.68 N	87.3 D	3.9 H
1/2 PG + 1/4 CTB	0.52 D	0.63 D	0.72 M	51.7 N	22.4 C
+ 0.30 ND	0.26 I	0.53 I	0.73 L	76.3 H	9.3 EF
+ 0.60 ND	0.14 M	0.41 O	0.75 K	89.0 C	3.8 H
1/2 PG + 1/2 CTB	0.36 F	0.59 F	0.83 G	61.1 L	21.1 C
+ 0.30 ND	0.19 K	0.48 K	0.85 F	81.3 F	8.3 FG
+ 0.60 ND	0.10 N	0.36 Q	0.87 E	91.3 A	2.9 H

^aR:FR = 655–665/725–735
^bPPE = Phytochrome photoequilibria
^cB:G = 420–490/500–570
^dPPF reduction = Percent reduction in PPF relative to full sun
^eUV-A PF = Photon flux between 340 and 399 nm
^fRosco Cinegel was used for CTB and Rosco e-colour + was used for PG and ND filters
^gData are presented as averages acquired on three different clear sky or mostly sunny days between 13:00 and 14:00 h: 27 May, 30 May, and 12 June 2020. 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). Data collected under full sun were on average; R:FR = 1.15, PPE = 0.72, B:G = 0.87, PPF = 1719 µmol m⁻² s⁻¹, UV-A PF = 86 µmol m⁻² s⁻¹

ISSN: 1746-4811