Table 2.
Effect of up to 28 h flooding of the soil on leaf gas exchange of 1-month-old tomato plants
| Treatment | A (μmol m−2 s−1) | Amax (μmol m−2 s−1) | Ci (μmol mol−1) | gs (mmol m−2 s−1) | dA/dCi (μmol m−2 s−1) | Γ (μmol mol−1) |
|---|---|---|---|---|---|---|
| WD 0–1 h | 11·18 ± 1·22 | 20·74 ± 1·28 | 181·75 ± 7·59 | 196·50 ± 26·53 | 0·073 ± 0·005 | 63·63 ± 2·40 |
| FL 1–2 h | 11·63 ± 0·72 | 22·30 ± 1·76 | 190·00 ± 2·66 | 222·50 ± 30·95 | 0·088 ± 0·008 | 62·73 ± 3·60 |
| WD 2–3 h | 10·11 ± 0·59 | 19·87 ± 1·67 | 195·57 ± 3·74 | 196·00 ± 7·07 | 0·075 ± 0·007 | 64·96 ± 2·14 |
| FL 3–4 h | 10·16 ± 1·12 | 18·31 ± 2·50 | 188·43 ± 4·90 | 194·86 ± 33·31 | 0·076 ± 0·007 | 61·37 ± 4·68 |
| WD 4–5 h | 10·84 ± 0·69 | 19·81 ± 1·92 | 197·86 ± 4·17 | 221·43 ± 18·97 | 0·077 ± 0·007 | 62·19 ± 2·94 |
| FL 5–6 h | 10·01 ± 0·65 | 16·77 ± 1·69 | 178·43* ± 4·15 | 165·00* ± 23·1 | 0·087 ± 0·005 | 66·12 ± 3·25 |
| WD 24–28 h | 11·27 ± 0·82 | 19·37 ± 1·39 | 198·27 ± 5·42 | 232·55 ± 22·35 | 0·097 ± 0·005 | 93·49 ± 9·21 |
| FL 24–28 h | 4·95* ± 0·58 | 13·88* ± 2·03 | 175·36* ± 6·38 | 69·00* ± 6·51 | 0·058* ± 0·009 | 129·85* ± 21·21 |
Measurements were made on the fifth oldest leaf using a Ciras-1 portable IRGA photosynthesis system. A/Ci curves were generated for well-drained and flooded plants and were used to calculate internal Ci, A, Amax, carboxylation efficiencies (dA/dCi) and the CO2 compensation point (Γ). Estimates of stomatal conductance (gs) were also made with the Ciras system. Results are means of 7–8 replicates with associated s.e.; asterisks indicate significant differences (P = 0·05) between flooded (FL) and well-drained control plants (WD).