Table I.
Effect of cold nights on cell division and cell expansion parameters during the photoperiod
| Growth Parametersa | Control | Cold Treated | Percent Changeb |
|---|---|---|---|
| Final leaf length (mm) | 658 ± 7 | 527 ± 5 | −20 |
| LER (mm/h) | 3.7 ± 0.2 | 2.9 ± 0.2 | −21 |
| Cell production (cells/h) | 30 ± 2 | 23 ± 1 | −22 |
| Division rate (cells/cell h) | 0.036 ± 0.004 | 0.022 ± 0.005 | −38 |
| Cell cycle duration (h) | 19 ± 2 | 32 ± 6 | 65 |
| Residence time in the meristem (h) | 191 ± 15 | 327 ± 43 | 71 |
| Dividing cells (no.) | 821 ± 94 | 1,060 ± 213 | 29 |
| Meristem size (mm) | 17 ± 6 | 16 ± 3 | NS |
| Mature cell size (μm) | 124 ± 10 | 127 ± 5 | NS |
| Residence time in the elongation zone (h) | 28 ± 1 | 37 ± 1 | 30 |
| Elongating cells (no.) | 705 ± 59 | 737 ± 22 | NS |
| Elongation zone size (mm) | 50 ± 2 | 45 ± 2 | NS |
a
Average ± se; n = 3, except for final leaf length and LER, n = 12. All parameters were determined at 48 h after leaf emergence.
b
Statistical significance based on one-way ANOVA tests (P < 0.05). NS, Not significant.