TABLE 1.
Analysis of variance (F, p) of midday net CO2 assimilation rate (A), stomatal conductance (g s), the ratio of leaf intercellular CO2 concentration to atmospheric CO2 concentration (c i:c a), and instantaneous water‐use efficiency (iWUE) measured in 10 genotypes of sorghum grown at ambient and elevated O3 on DOY 183, 204 and 225 in 2018 and in 5 genotypes of sorghum grown at ambient and elevated O3 on DOY 205, 220 and 235 in 2019 at the FACE facility.
| A (μmol m−2 s−1) | g s (mol m−2 s−1) | c i: c a | iWUE (μmol mol−1) | |||||
|---|---|---|---|---|---|---|---|---|
| 2018 | 2019 | 2018 | 2019 | 2018 | 2019 | 2018 | 2019 | |
| O3 | 2.62, 0.11 | 7.93, 0.006 | 0.001, 0.97 | 2,09, 0.15 | 3.83, 0.052 | 1.53, 0.22 | 3.38, 0.067 | 0.001, 0.98 |
| Genotype (G) | 3.41, 0.001 | 5.99, <0.001 | 2.31, 0.018 | 4.36, 0.003 | 1.86, 0.06 | 4.06, 0.005 | 1.48, 0.16 | 2.59, 0.042 |
| O3 × G | 0.53, 0.85 | 0.081, 0.99 | 0.55, 0.84 | 0.11, 0.98 | 0.64, 0.76 | 0.65, 0.63 | 0.75, 0.67 | 0.54, 0.71 |
| Day of year (DOY) | 412.8, <0.001 | 86.7, <0.001 | 281.6, <0.001 | 43.9, <0.001 | 60.3, <0.001 | 1.41, 0.25 | 109.1, <0.001 | 2.62, 0.079 |
| O3 × DOY | 1.68, 0.19 | 0.18, 0.83 | 1.17, 0.31 | 0.29, 0.75 | 0.013, 0.99 | 1.76, 0.18 | 0.014, 0.99 | 1.49, 0.23 |
| G × DOY | 1.06, 0.40 | 2.66, 0.011 | 1.14, 0.32 | 2.39, 0.022 | 1.34, 0.17 | 2.27, 0.029 | 1.64, 0.054 | 2.28, 0.029 |
| O3 × G × DOY | 0.93, 0.55 | 0.31, 0.96 | 0.91, 0.57 | 0.12, 0.99 | 1.36, 0.16 | 0.37, 0.94 | 1.64, 0.055 | 0.31, 0.96 |
Note: Significant effects are shown in boldface.