Table 3.
Parameters of plant water relations and isotopic composition of S. viridis
Each variable was analysed with a separate two-factor ANOVA. The Δ18OLW and Δ18OBL values were calculated using each of the possible water sources (source water in parentheses). P-values for the ANOVAs are located on the right side (*P<0.05, **P<0.01, and ***P<0.001, ns not significant). Columns 1, 2 and ‘I’ are the factors ‘differential irrigation’ (1), ‘collection time’ (2), and the differential irrigation × collection time interaction (I). Means±SE within a row, followed by the same superscripted letters, are not significantly different. Other factors are given in Supplementary Tables S1 and S2 at JXB online.
| Parameters | Collection 1 | Collection 2 | Collection 3 | ANOVA | |||||
|---|---|---|---|---|---|---|---|---|---|
| Well-watered | Water-limited | Well-watered | Water-limited | Well-watered | Water-limited | 1 | 2 | I | |
| Total water use (l) | 5.33 ± 0.38 | 2.13 ± 0.06 | 6.97 ± 0.29 | 2.86 ± 0.06 | 7.94 ± 0.56 | 3.24 ± 0.2 | *** | *** | ns |
| Fresh aboveground biomass (g) | 192.3 ± 10.7 | 74.7 ± 2.1 | 229.4 ± 5.1 | 87.8 ± 1.3 | 234.5 ± 13.8 | 77.0 ± 1.6 | *** | ** | ns |
| Dry aboveground biomass (g) | 31.8 ± 2.1 | 16.1 ± 0.4 | 41.6 ± 2.2 | 21.0 ± 0.3 | 45.4 ± 3.3 | 22.6 ± 0.6 | *** | *** | ns |
| Number of tillers | 125 ± 6 | 74 ± 3 | 142 ± 4 | 78 ± 4 | 145 ± 17 | 77 ± 1 | *** | ns | ns |
| Δ18OLW (root crown) | 21.0 ± 0.3c | 21.8 ± 0.7bc | 19.5 ± 0.4c | 21.7 ± 0.6bc | 23.8 ± 0.5b | 29.4 ± 0.7a | *** | *** | ** |
| Δ18OLW (soil) | 20.4 ± 0.3 | 22.4 ± 0.6 | 19.4 ± 0.4 | 21.7 ± 0.6 | 24.2 ± 0.6 | 28.8 ± 0.5 | *** | *** | ns |
| Δ18OLW (irrigation) | 21.4 ± 0.3cd | 24.0 ± 0.8b | 20.1 ± 0.5d | 23.3 ± 0.5bc | 25.0 ± 0.5b | 31.7 ± 0.6a | *** | *** | ** |
| Δ18OBL (root crown) | 43.5 ± 1.1 | 45.2 ± 0.8 | 43.6 ± 0.5 | 44.2 ± 0.6 | 44.7 ± 0.8 | 45.4 ± 0.7 | ns | ns | ns |
| Δ18OBL (soil) | 43.2 ± 0.9 | 45.8 ± 0.8 | 43.6 ± 0.6 | 44.2 ± 0.6 | 45.1 ± 0.8 | 44.9 ± 0.5 | ns | ns | ns |
| Δ18OBL (irrigation) | 44.2 ± 0.9 | 47.3 ± 0.7 | 44.2 ± 0.7 | 45.7 ± 0.6 | 45.7 ± 0.8 | 47.7 ± 0.6 | ** | ns | ns |
| δ13CBL | −13.4 ± 0.1 | −14.4 ± 0.1 | −13.4 ± 0.1 | −14.5 ± 0.1 | −13.5 ± 0.04 | −14.6 ± 0.1 | *** | ns | ns |
| δ18ORC | −16.5 ± 0.2 | −14.9 ± 0.2 | −16.5 ± 0.2 | −15.5 ± 0.2 | −15.9 ± 0.1 | −14.7 ± 0.2 | *** | ** | ns |
| δ18OSW | −16.0 ± 0.1b | −15.5 ± 0.2b | −16.4 ± 0.1b | −16.3 ± 0.3b | −16.3 ± 0.2b | −14.1 ± 0.2a | *** | * | ** |
| C i/Ca | 0.41 ± 0.03 | 0.26 ± 0.06 | 0.37 ± 0.02 | 0.18 ± 0.02 | 0.36 ± 0.02 | 0.13 ± 0.02 | *** | * | ns |
| g s (mol H2O m−2 s−1) | 0.26 ± 0.01a | 0.22 ± 0.02a | 0.26 ± 0.01a | 0.15 ± 0.02b | 0.26 ± 0.02a | 0.06 ± 0.01c | *** | *** | *** |
| E (mmol H2O m−2 s−1) | 5.03 ± 0.23ab | 4.57 ± 0.19b | 4.88 ± 0.14ab | 3.27 ± 0.36c | 5.6 ± 0.16a | 1.87 ± 0.19d | *** | *** | *** |
| A net (µmol CO2 m−2s−1) | 28.3 ± 0.8ab | 32.3 ± 1.2a | 31.0 ± 0.6ab | 25.4 ± 2.2b | 31.2 ± 0.6a | 12.1 ± 1.5c | *** | *** | *** |
| Water/leaf area (l H2O m dry leaf−2) | 0.14 ± 0.01 | 0.13 ± 0.01 | 0.12 ± 0.003 | 0.11 ± 0.002 | 0.11 ± 0.001 | 0.10 ± 0.01 | ns | *** | ns |
| TEinstantaneous (Anet/E) | 5.68 ± 0.31 | 7.13 ± 0.47 | 6.36 ± 0.12 | 7.86 ± 0.24 | 5.59 ± 0.11 | 6.44 ± 0.31 | *** | ** | ns |
| TEintrinsic (Anet/gs) | 109.0 ± 5.6 | 151.6 ± 12.8 | 121.1 ± 3.8 | 170.1 ± 5.3 | 123.5 ± 5.4 | 193.4 ± 5.1 | *** | ** | ns |
| TEplant (g biomass l H2O−1) | 5.98 ± 0.09 | 7.57 ± 0.10 | 5.96 ± 0.09 | 7.35 ± 0.09 | 5.69 ± 0.08 | 7.06 ± 0.16 | *** | ns | ns |
| TEw (derived from δ13CBL) | 5.47 ± 0.22 | 7.25 ± 0.13 | 5.49 ± 0.10 | 7.43 ± 0.22 | 5.64 ± 0.07 | 7.61 ± 0.09 | *** | ns | ns |
| Effective leaf length (mm) | 13.58 ± 1.9a | 10.84 ± 3.9ab | 16.88 ± 2.1a | 11.92 ± 2.2a | 9.16 ± 4.1ab | 1.76 ± 1b | * | ** | ns |
| Leaf length (cm) | 19.2 ± 0.2 | 17.5 ± 0.1 | 19.9 ± 0.8 | 16.7 ± 0.4 | 19.6 ± 0.7 | 15.7 ± 0.2 | *** | ns | ns |