Table 4. Carbon isotope composition.
The C isotope composition (‰) of leaf-respired CO2 (δ13CR), leaf soluble carbohydrates (δ13Csugar), leaf starch (δ13Cstarch) and leaf lipids (δ13Clipid) at 8 pm and 4 am, respectively. The carbon isotope composition of leaf bulk tissue (δ13Cbiomass) was measured once at 8 pm. The amplitude of the nighttime variation in δ13CR (Variation in δ13CR) was estimated as δ13CR-8pm—δ13CR-4am. Differences in the δ13CR between the samples collected at 8 pm and 4 am were assessed by One-way analysis of variance (ANOVA) and the P values are presented.
| Species | δ13CR-8pm (‰) | δ13CR-4am (‰) | Variation in δ13CR | P | δ13Cbiomass (‰) | δ13Csugar-8pm (‰) | δ13Csugar-4am (‰) | δ13Cstarch-8pm (‰) | δ13Cstarch-4am (‰) | δ13Cipid-8pm (‰) | δ13Cipid-4am (‰) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| L. chinensis | -22.7±0.17 | -24.5±0.16 | 1.8±0.15 | <0.01 | -26.6±0.21 | -27.4±0.55 | -27.9±0.23 | -24.7±0.17 | -25.3±0.38 | -29.9±0.36 | -29.3±0.47 |
| P. australis | -21.7±0.09 | -23.5±0.10 | 1.8±0.12 | <0.01 | -25.8±0.13 | -29.0±0.17 | -29.5±0.10 | -22.9±0.32 | -24.2±0.10 | -30.2±0.31 | -29.5±0.32 |
| L. bicolor | -24.9±0.13 | -26.6±0.16 | 1.7±0.26 | <0.01 | -28.5±0.09 | -30.1±0.20 | -30.9±0.30 | -29.6±0.06 | -30.0±0.10 | -30.0±0.22 | -30.5±0.25 |
| M. asiatica | -21.2±0.17 | -24.7±0.16 | 3.5±0.32 | <0.01 | -26.8±0.16 | -25.5±0.37 | -25.6±0.30 | -24.0±0.08 | -24.5±0.14 | -31.3±0.12 | -30.6±0.15 |
| P. simonii | -22.9±0.24 | -25.6±0.17 | 2.7±0.26 | <0.01 | -27.8±0.15 | -27.4±0.17 | -28.5±0.04 | -26.1±0.25 | -28.5±0.10 | -30.6±0.32 | -31.8±0.33 |
| P. salicina | -22.6±0.15 | -25.5±0.22 | 3.0±0.31 | <0.01 | -26.9±0.18 | -25.9±0.26 | -25.6±0.08 | -25.9±0.21 | -25.6±0.16 | -30.5±0.13 | -29.9±0.17 |
| C. glaucum | -26.0±0.32 | -26.1±0.28 | 0.2±0.47 | 0.72 | -28.5±0.18 | -32.6±0.36 | -33.3±0.26 | -26.6±0.39 | -25.4±0.36 | -30.9±0.25 | -30.3±0.15 |
| G. max | -22.6±0.16 | -24.7±0.10 | 2.2±0.25 | <0.01 | -27.8±0.07 | -28.6±0.35 | -28.5±0.35 | -26.8±0.12 | -27.7±0.10 | -32.4±0.24 | -32.2±0.25 |
| H. annuus | -26.3±0.31 | -28.1±0.26 | 1.9±0.73 | <0.01 | -28.2±0.36 | -27.7±0.26 | -26.8±0.18 | -27.0±0.25 | -27.6±0.11 | -32.3±0.42 | -32.1±0.16 |
| S. amara | -25.5±0.16 | -25.0±0.30 | 0.5±0.32 | 0.17 | -28.4±0.12 | -29.1±0.05 | -29.4±0.06 | -27.0±0.12 | -26.8±0.23 | -31.4±0.09 | -31.8±0.23 |
| V. radiata | -19.9±0.19 | -23.4±0.07 | 3.5±0.24 | <0.01 | -26.5±0.09 | -27.5±0.04 | -27.6±0.15 | -26.4±0.07 | -26.7±0.11 | -33.0±0.32 | -30.6±1.06 |
| V. unguiculata | -23.5±0.32 | -27.0±0.41 | 3.5±0.41 | <0.01 | -29.3±0.22 | -29.3±0.60 | -28.1±0.23 | -27.4±0.18 | -28.8±0.21 | -31.1±0.16 | -30.8±0.24 |
| X. sibiricum | -23.7±0.22 | -24.6±0.26 | 1.0±0.41 | 0.02 | -26.2±0.27 | -25.5±0.14 | -25.3±0.29 | -24.9±0.29 | -24.4±0.26 | -29.5±0.20 | -29.1±0.20 |
| C. virgata | -8.3±0.17 | -10.2±0.10 | 2.0±0.16 | <0.01 | -12.8±0.26 | -15.5±0.24 | -15.6±0.32 | -11.8±0.07 | -12.1±0.38 | -21.7±0.28 | -21.9±0.36 |
| E. crusgalli | -9.6±0.12 | -11.3±0.08 | 1.8±0.18 | <0.01 | -13.2±0.35 | -15.7±0.28 | -14.1±0.36 | -11.6±0.41 | -11.2±0.13 | -20.1±0.34 | -17.9±0.70 |
| H. altissima | -9.4±0.10 | -11.4±0.14 | 2.0±0.21 | <0.01 | -12.8±0.31 | -15.3±0.27 | -15.0±0.21 | -11.7±0.16 | -12.2±0.13 | -21.3±0.18 | -21.3±0.28 |
| P. miliaceum | -8.9±0.33 | -13.1±0.14 | 4.1±0.33 | <0.01 | -13.3±0.13 | -16.0±0.46 | -18.1±0.58 | -11.4±0.12 | -11.9±0.13 | -21.3±0.16 | -21.1±0.61 |
| S. italica | -8.6±0.19 | -11.9±0.30 | 3.2±0.39 | <0.01 | -12.1±0.14 | -17.7±0.16 | -16.9±0.46 | -11.2±0.21 | -11.1±0.13 | -22.2±0.51 | -20.8±0.39 |
| S. viridis | -7.3±0.14 | -9.5±0.17 | 2.2±0.27 | <0.01 | -12.2±0.07 | -13.5±0.19 | -19.4±0.24 | -11.4±0.04 | -11.8±0.29 | -21.1±0.52 | -20.5±0.64 |
| S. bicolor | -9.5±0.13 | -12.2±0.20 | 2.7±0.18 | <0.01 | -12.3±0.19 | -13.2±0.20 | -12.9±0.32 | -10.8±0.19 | -11.5±0.59 | -22.0±0.24 | -21.2±0.40 |
| Z. mays | -5.3±0.22 | -11.1±0.28 | 5.8±0.24 | <0.01 | -12.4±0.19 | -14.9±0.71 | -13.6±0.28 | -10.3±0.09 | -11.0±0.44 | -22.0±0.68 | -21.9±0.35 |
| A. retroflexus | -7.6±0.26 | -12.3±0.31 | 4.7±0.36 | <0.01 | -12.2±0.13 | -16.6±0.74 | -16.5±0.58 | -10.8±0.45 | -12.4±0.39 | -21.0±0.50 | -20.9±0.45 |
Data are reported as the mean ±1 SE (n = 5)