Table 2.
Effects of seed single or sequential application of antioxidants on photosynthetic efficiency of 100 mM NaCl-salt-stressed cucumber transplants.
| Treatments | Stomatal Conductance (mmol−2 S−1) | SPAD Chlorophyll | Fv/Fm | Performance Index (%) |
|---|---|---|---|---|
| Control | 193 ± 5 d | 42.1 ± 2.2 ab | 0.83 ± 0.06 a | 3.64 ± 0.24 ab |
| AsA | 241 ± 7 abc | 42.4 ± 1.0 ab | 0.83 ± 0.05 a | 3.75 ± 0.10 ab |
| Pro | 247 ± 5 abc | 42.8 ± 0.6 ab | 0.83 ± 0.05 a | 3.73 ± 0.12 ab |
| GSH | 254 ± 6 a | 42.9 ± 0.9 ab | 0.83 ± 0.04 a | 3.78 ± 0.14 a |
| AsA-Pro-GSH | 257 ± 8 a | 44.7 ± 1.4 a | 0.84 ± 0.05 a | 3.78 ± 0.12 a |
| NaCl | 142 ± 4 e | 33.8 ± 2.0 e | 0.76 ± 0.04 b | 3.03 ± 0.35 c |
| NaCl + AsA | 232 ± 8 c | 38.9 ± 1.8 cd | 0.82 ± 0.05 a | 3.46 ± 0.30 b |
| NaCl + Pro | 234 ± 5 bc | 38.6 ± 1.9 d | 0.82 ± 0.04 a | 3.46 ± 0.29 b |
| NaCl + GSH | 234 ± 7 bc | 39.0 ± 0.8 cd | 0.82 ± 0.04 a | 3.48 ± 0.31 b |
| NaCl + AsA-Pro-GSH | 252 ± 6 ab | 41.4 ± 1.5 bc | 0.84 ± 0.05 a | 3.72 ± 0.19 ab |
Means with the same letter within each trait are not significantly differed at p ≤ 0.05. AsA = ascorbic acid, Pro = proline, GSH = glutathione, and AsA-Pro-GSH = sequential application of different antioxidants. Fv/Fm = maximum quantum yield of PSII = efficiency of the photosystem 2.