Table 1.
Mean WUE during the high light period (WUEHL) and low light period (WUELL) in four C3 species and five C4 species grown under high and low nitrogen conditions.
| Type | Species | N | WUEHL | WUELL |
|---|---|---|---|---|
| (μmol CO2 mmol H2O‒1) | (μmol CO2 mmol H2O‒1) | |||
| C3 | Triticum aestivum | HN | 3.54 ± 0.27 | 1.43 ± 0.28 |
| LN | 3.22 ± 0.18 | 3.01 ± 0.52 | ||
| Avena sativa | HN | 2.98 ± 0.08 | 0.80 ± 0.04 | |
| LN | 3.89 ± 1.01 | 1.28 ± 0.26 | ||
| Hordeum vulgare | HN | 4.42 ± 0.24 | 1.69 ± 0.14 | |
| LN | 3.64 ± 0.19 | 1.81 ± 0.29 | ||
| Lolium multiflorum | HN | 3.53 ± 0.19 | 2.66 ± 0.28 | |
| LN | 1.82 ± 0.13 | 1.38 ± 0.24 | ||
| C4 | Eleusine coracana | HN | 7.72 ± 0.30 | 6.80 ± 0.43 |
| LN | 5.96 ± 0.18 | 6.65 ± 0.25 | ||
| Sorghum bicolor | HN | 9.90 ± 0.27 | 6.06 ± 0.46 | |
| LN | 9.71 ± 0.13 | 6.26 ± 0.73 | ||
| Panicum miliaceum | HN | 9.36 ± 0.29 | 9.49 ± 0.50 | |
| LN | 10.27 ± 0.22 | 8.11 ± 0.34 | ||
| Zea mays | HN | 10.16 ± 0.23 | 5.04 ± 0.78 | |
| LN | 7.38 ± 0.40 | 4.23 ± 0.69 | ||
| Zea nicaraguensis | HN | 9.70 ± 0.36 | 3.46 ± 0.16 | |
| LN | 7.99 ± 0.54 | 6.14 ± 0.63 | ||
| C3, C4 | *** | *** | ||
| Two-way ANOVA | N | ** | NS | |
| C3, C 4 × N | NS | NS |
WUEHL and WUELL were calculated as the ratio of photosynthetic ratio (A) to transpiration rate (E) during the high light period and the second and third low light period, respectively (Figure 2). Data are the mean ± se (n = 4). The effects of photosynthetic types (C3 or C4), nitrogen conditions (HN or LN), and their interaction on the characteristics were determined by two-way ANOVA (***P < 0.001, **P < 0.01, *P < 0.05, NS, P > 0.05).