Table 3.
Effects of Mg supply on photosynthetic parameters of light and CO2 response curves.
| Species | Treatment | α | CE | V cmax (μmol m−2 s−1) | J max (μmol m−2 s−1) | J max/V cmax | C trans (μmol mol−1) |
|---|---|---|---|---|---|---|---|
| Rice | 0.01 mM | 0.046 ± 0.001b | 0.064 ± 0.007c | 53.0 ± 7.0b | 88 ± 12c | 1.65 ± 0.01b | 432 ± 3b |
| 0.1 mM | 0.051 ± 0.001b | 0.096 ± 0.007b | 85.3 ± 8.4a | 154 ± 9b | 1.81 ± 0.09a | 505 ± 46a | |
| 1 mM | 0.058 ± 0.005a | 0.118 ± 0.003a | 99.4 ± 6.4a | 180 ± 15a | 1.81 ± 0.03a | 508 ± 17a | |
| Cucumber | 0.01 mM | 0.027 ± 0.005c | 0.034 ± 0.004c | 38.3 ± 2.1c | 63 ± 6c | 1.64 ± 0.04b | 426 ± 16b |
| 0.1 mM | 0.051 ± 0.000b | 0.060 ± 0.006b | 58.9 ± 2.0b | 99 ± 5b | 1.69 ± 0.04b | 446 ± 17b | |
| 1 mM | 0.058 ± 0.004a | 0.081 ± 0.003a | 69.3 ± 5.7a | 122 ± 13a | 1.76 ± 0.03a | 481 ± 15a | |
| Rice | ** | *** | *** | *** | * | * | |
| Cucumber | * | ** | ** | ** | ** | ** |
Data represent mean ± standard deviation (SD) of three replicates for α, CE, V cmax, J max, J max/V cmax, and C trans. Different letters indicate statistically significant differences (P< 0.05) between three Mg treatments. In the last two lines, the significance of each correlation between Mg concentration and photosynthetic parameters was represented by asterisks: *P< 0.05; **P< 0.01; ***P< 0.001; ns, no significant difference.
α, apparent quantum yield; CE, carboxylation rate; V cmax, the maximum Rubisco carboxylation rate; J max, the maximum rate of electron transport; C trans, CO2 concentration in chloroplasts at which the transition from Rubisco to RuBP regeneration limitation occurs.