Table 1.
LED and solar light intensity (PAR and FR) and calculated PSS values for the five treatments without solar light (EXP1) or with solar light (EXP2).
| EXP1 (LED) |
EXP2 (LED + solar) |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Treatment | PSS0.70 | PSS0.73 | PSS0.80 | PSS0.88 | EOD | PSS0.70 | PSS0.73 | PSS0.80 | PSS0.87 | EOD |
| PSS | 0.70 | 0.73 | 0.80 | 0.88 | 0.88/0.1∗ | 0.70 | 0.73 | 0.80 | 0.87 | 0.87/0.1∗ |
| PAR LED (μmol m-2 s-1) | 149 ± 0.1 | 148 ± 0.4 | 149 ± 0.1 | 149 ± 0.4 | 149 ± 0.2 | 159 ± 2 | 152 ± 2 | 146 ± 3 | 149 ± 6 | 155 ± 5 |
| PAR solar (μmol m-2 s-1) | 0 | 0 | 0 | 0 | 0 | 40 ± 2 | 39 ± 6 | 38 ± 3 | 43 ± 3 | 50 ± 2 |
| PAR solar fraction (%) | 0 | 0 | 0 | 0 | 0 | 9.3 | 9.2 | 9.3 | 10.6 | 11.3 |
| FR solar (μmol m-2 s-1) | 0 | 0 | 0 | 0 | 0 | 11 ± 1 | 11 ± 1 | 10 ± 1 | 11 ± 1 | 13 ± 2 |
| FR LED (μmol m-2 s-1) | 154 ± 0.8 | 119 ± 1.1 | 54 ± 0.7 | 0 | 17 ± 0.4 | 154 ± 1 | 113 ± 2 | 49 ± 2 | 0 | 17 ± 0.5 |
The values are the means of three measurements at plant height per plot (three plots per treatment). The standard deviation was calculated based on the averages per plot. Data was acquired by spectroradiometer on the 12th of February (9:20–11:20 AM solar time) and on the 17th of March (9:20–10:20 AM solar time) for EXP 1 and 2, respectively. In EXP2, PSS values are based on the combination of lamp and solar light (the PSS values of lamp light were equal to those of EXP1). EOD is end-of-day lighting, meaning the FR lamps were on for 15 min just after the end of the 16-h photoperiod. ∗The first value refers to the period that the red/blue LEDs operated, the second value when only the FR LEDs operated.