Table 2.
Net CO2 assimilation rate and transport parameters in seedlings of two maize inbred lines treated with low temperature (14 °C) for different time periods
| Net CO2 assimilation rate (μmol CO2 m−2 s−1) |
Time taken for 14C-photosynthates to appear in the transport path, AT (min) |
Radioactivity exported from leaves, RL (% of total radioactivity incorporated) |
|||||
|---|---|---|---|---|---|---|---|
| Treatment | KW 1074 | CM 109 | KW 1074 | CM 109 | KW 1074 | CM 109 | |
| row\column | I | II | III | IV | V | VI | |
| 1 | Growth at 24 °C, measurement at 24 °C | 16·1 ± 1·4a | 17·8 ± 2·1a | 5·8 ± 1·2a | 6·9 ± 0·6a | 56·3 ± 6·1a | 55·0 ± 8·8a |
| 2 | Growth at 24 °C, measurement at 14 °C | 11·9 ± 1·5b | 10·8 ± 1·6b | 9·3 ± 1·1b | 15·0 ± 1·2c | 44·3 ± 4·0b | 37·1 ± 4·6b |
| 3 | Chilling for 1 h, measurement at 24 °C | 16·1 ± 3·0a | 12·3 ± 1·8b | 5·8 ± 0·7a | 7·9 ± 1·3ab | 63·8 ± 13·2a | 44·1 ± 5·6b |
| 4 | Chilling for 4 h, measurement at 24 °C | 15·0 ± 1·3a | 11·4 ± 0·5b | 5·0 ± 0·9a | 9·8 ± 0·5b | 61·0 ± 7·5a | 38·3 ± 4·1b |
| 5 | Chilling for 28 h, measurement at 24 °C | 14·3 ± 0·8a | 12·6 ± 1·9b | 7·1 ± 0·6a | 10·8 ± 0·8b | 47·4 ± 4·1b | 35·0 ± 5·5b |
| 6 | Chilling for 28 h, measurement at 14 °C | 9·6 ± 2·9b | 8·7 ± 1·3b | 9·9 ± 0·6b | 17·8 ± 1·2c | 36·3 ± 4·8c | 16·0 ± 3·1c |
Data represent means ± s.d. for 9–12 plants.
Significant differences (P < 0·05) within columns, estimated by analysis of variance, are indicated by different letters.