Table 1.
Twelve-hour mean ozone concentration and indices of ozone exposure (AOT40, ozone concentrations accumulated over a threshold of 40 ppb) and stomatal uptake (POD0, phytotoxic ozone dose, expressed as the accumulated stomatal flux of ozone) to which cowpea plants were subjected in the following treatments: Control (C), Drought (D), Ozone (O), Ozone + Drought (OD). Mean ± SD are shown (n = 4). Ozone concentration and AOT40 were averaged from the values recorded in 4 identical chambers. Ozone stomatal uptake (POD0) was averaged from 4 biological replicates. Control (C) and drought-treated (D) plants were supplied with activated charcoal-filtered air and ozone concentration was close to zero (nd, not detected).
| Cultivar | Treatment | 12-h Mean (O3) (ppb) | AOT40 (ppm·h) | POD0 (mmol·m−2) |
|---|---|---|---|---|
| EPACE-1 | C | nd | nd | nd |
| D | nd | |||
| O | 130.4 ± 5.2 | 16.7 ± 1.0 | 3.8 ± 0.7 | |
| OD | 2.9 ± 0.5 | |||
| IT83-D | C | nd | nd | nd |
| D | nd | |||
| O | 130.4 ± 5.2 | 16.7 ± 1.0 | 4.6 ± 1.2 | |
| OD | 3.1 ± 1.4 |