The factor loadings on the 7 physiological variables of
| Variables | Factor 1 | Factor 2 |
|---|---|---|
| B:R | –0.147 | –0.690 |
| W | 0.630 | 0.324 |
| ΔT | –0.761 | –0.218 |
| Ci | 0.035 | 0.719 |
| E | 0.925 | 0.209 |
| Pn | 0.800 | –0.302 |
| Φ | –0.145 | –0.759 |
B:R: amount of blue light per red light; W: amount of white light per red light; ΔT: difference between leaf and air temperatures; Ci: intercellular CO2 pressure; E: transpiration rate; Pn: net photosynthetic rate; Φ: photosynthetic quantum efficiency on the incident light.