Table 1.
Gas exchange parameters measured at growth CO2 concentration under Ea in F1 and Eg and Ea in F5
| Generation | Stage | CO2 |
A
growth
(μmol m−2 s−1) |
g
s
(mol m−2 s−1) |
T
r
(mmol m−2 s−1) |
V
cmax25
(μmol m−2 s−1) |
J
max25
(μmol m−2 s−1) |
|---|---|---|---|---|---|---|---|
| F1 | Jointing | A | 29.6 (0.5) b | 0.338 (0.014) a | 5.52 (0.21) a | 115.7 (2.3) a | 139.6 (3.5) a |
| E a | 33.1 (0.8) a | 0.254 (0.020) b | 4.69 (0.32) b | 103.2 (2.3) b | 131.0 (2.4) b | ||
| Filling | A | 17.3 (0.4) b | 0.148 (0.007) a | 2.60 (0.09) a | 82.0 (1.8) a | 145.3 (3.4) a | |
| E a | 22.3 (0.4) a | 0.133 (0.007) a | 2.31 (0.08) b | 75.2 (1.0) b | 134.0 (3.6) b | ||
| F5 | Jointing | A | 25.3 (0.4) b | 0.211 (0.012) a | 4.57 (0.27) a | 102.9 (2.1) a | 129.8 (2.9) a |
| E g | 32.0 (0.6) a | 0.203 (0.014) a | 3.84 (0.17) a | 100.5 (1.3) a | 128.0 (3.0) a | ||
| E a | 31.9 (0.5) a | 0.207 (0.019) a | 3.97 (0.22) a | 96.1 (2.4) a | 127.0 (2.9) a | ||
| Filling | A | 15.9 (0.5) b | 0.140 (0.005) a | 2.22 (0.09) a | 69.4 (2.0) a | 123.7 (3.2) a | |
| E g | 21.9 (0.9) a | 0.121 (0.010) a | 2.04 (0.15) a | 69.3 (2.3) a | 129.8 (3.8) a | ||
| E a | 22.1 (0.4) a | 0.116 (0.007) a | 1.95 (0.09) a | 69.3 (1.7) a | 133.6 (2.9) a |
Abbreviations: Agrowth, net photosynthetic rate at growth CO2 concentration; gs, stomatal conductance to CO2; Jmax25, the maximum electron transport rate at 25 °C; Tr, transpiration rate; Vcmax25, the maximum rate of Rubisco carboxylation at 25 °C. Values are the mean (s.e.m.), n = 4. Different lowercase letters indicate significant differences among the CO2 treatments (P < 0.05).