Table 1.
Photosynthetic rate, stomatal conductance, Intercellular CO2 concentration, Transpiration rate, water use efficiency (WUE) and intercellular to ambient CO2 concentration (Ci/Ca) of iceberg lettuce expressed as mean ± standard error, subjected to different DLI levels.
| Treatments | Photosynthetic rate (Pn) | Stomatal Conductance | Intercellular CO2 concentration | Transpiration rate (E) | WUE (Pn/E) | Ci/Ca |
|---|---|---|---|---|---|---|
| CT | 8.06 ± 0.02 a | 0.16 ± 0.001 b | 357.64 ± 0.59 b | 1.57 ± 0.001 ab | 5.14 ± 0.009 c | 0.90 ± 0.001 a |
| CM | 6.67 ± 0.07 b | 0.14 ± 0.001 b | 404.95 ± 0.35 a | 1.45 ± 0.008 a | 4.59 ± 0.005 bc | 0.81 ± 0.002 b |
| CL | 4.74 ± 0.03 c | 0.20 ± 0.004 a | 361.55 ± 0.94 b | 1.38 ± 0.002 a | 3.44 ± 0.015 a | 0.79 ± 0.001 b |
| 12 h/8.64 DLI | 7.06 ± 0.23 db | 0.09 ± 0.001 cd | 398.84 ± 0.98 a | 1.46 ± 0.004 a | 4.84 ± 0.017 bc | 0.88 ± 0 .005 a |
| 16 h/11.5 DLI | 8.60 ± 0.21 a | 0.13 ± 0.004 bd | 445.20 ± 0.32 c | 1.48 ± 0.009 a | 6.03 ± 0.042 d | 0.95 ± 0.003 c |
| 20 h/14.4 DLI | 7.90 ± 0.36 a | 0.12 ± 0.002 d | 462.80 ± 0.88 d | 1.89 ± 0.002 b | 4.22 ± 0.021 b | 0.94 ± 0.002 c |
Means followed by similar letter in a same column represents no significant difference (CT control top layer, CM control middle layer, CB control bottom layer).